Diff: rfc9843xml2.original.xml

	rfc9843xml2.original.xml	rfc9843.xml

	<?xml version="1.0"?>	<?xml version='1.0' encoding='UTF-8'?>
	<!DOCTYPE rfc SYSTEM "rfc2629.dtd" [
	<!ENTITY RFC2119 PUBLIC "" "http://xml.resource.org/public/rfc/bibxml/reference.
	RFC.2119.xml">
	<!ENTITY RFC5305 PUBLIC "" "http://xml.resource.org/public/rfc/bibxml/reference.
	RFC.5305.xml">
	<!ENTITY RFC7684 PUBLIC "" "http://xml.resource.org/public/rfc/bibxml/reference.
	RFC.7684.xml">
	<!ENTITY RFC5311 PUBLIC "" "http://xml.resource.org/public/rfc/bibxml/reference.
	RFC.5311.xml">
	<!ENTITY RFC9346 PUBLIC "" "http://xml.resource.org/public/rfc/bibxml/reference.
	RFC.9346.xml">
	<!ENTITY RFC5120 PUBLIC "" "http://xml.resource.org/public/rfc/bibxml/reference.
	RFC.5120.xml">
	<!ENTITY RFC8570 PUBLIC "" "http://xml.resource.org/public/rfc/bibxml/reference.
	RFC.8570.xml">
	<!ENTITY RFC7471 PUBLIC "" "http://xml.resource.org/public/rfc/bibxml/reference.
	RFC.7471.xml">
	<!ENTITY RFC3630 PUBLIC "" "http://xml.resource.org/public/rfc/bibxml/reference.
	RFC.3630.xml">
	<!ENTITY RFC9479 PUBLIC "" "http://xml.resource.org/public/rfc/bibxml/reference.
	RFC.9479.xml">
	<!ENTITY RFC9492 PUBLIC "" "http://xml.resource.org/public/rfc/bibxml/reference.
	RFC.9492.xml">
	<!ENTITY RFC8362 PUBLIC "" "http://xml.resource.org/public/rfc/bibxml/reference.
	RFC.8362.xml">
	<!ENTITY RFC9350 PUBLIC "" "http://xml.resource.org/public/rfc/bibxml/reference.
	RFC.9350.xml">
	<!ENTITY RFC5715 PUBLIC "" "http://xml.resource.org/public/rfc/bibxml/reference.
	RFC.5715.xml">
	<!ENTITY RFC9356 PUBLIC "" "http://xml.resource.org/public/rfc/bibxml/reference.
	RFC.9356.xml">
	<!ENTITY RFC5392 PUBLIC "" "http://xml.resource.org/public/rfc/bibxml/reference.
	RFC.5392.xml">
	<!ENTITY RFC5329 PUBLIC "" "http://xml.resource.org/public/rfc/bibxml/reference.
	RFC.5329.xml">
	<!ENTITY RFC8668 PUBLIC "" "http://xml.resource.org/public/rfc/bibxml/reference.
	RFC.8668.xml">
	<!ENTITY RFC8174 PUBLIC "" "http://xml.resource.org/public/rfc/bibxml/reference.
	RFC.8174.xml">
	<!ENTITY RFC4655 PUBLIC "" "http://xml.resource.org/public/rfc/bibxml/reference.
	RFC.4655.xml">
	<!ENTITY RFC1195 PUBLIC "" "http://xml.resource.org/public/rfc/bibxml/reference.
	RFC.1195.xml">
	<!ENTITY RFC2328 PUBLIC "" "http://xml.resource.org/public/rfc/bibxml/reference.
	RFC.2328.xml">
	]>
	<?rfc toc="yes"?>
	<?rfc tocompact="yes"?>
	<?rfc tocdepth="3"?>
	<?rfc tocindent="yes"?>
	<?rfc symrefs="yes"?>
	<?rfc sortrefs="yes"?>
	<?rfc comments="yes"?>
	<?rfc inline="yes"?>
	<?rfc compact="yes"?>
	<?rfc subcompact="no"?>
	<rfc category="std" docName="draft-ietf-lsr-flex-algo-bw-con-22" ipr="trust20090
	2">
	<front>
	<title abbrev="IGP Flex-Algorithm: Bandwidth, Delay, Metric">
	IGP Flexible Algorithms: Bandwidth, Delay, Metrics and Constraints</title>

	<author initials="S." surname="Hegde" fullname="Shraddha Hegde">
	<organization>Juniper Networks Inc.</organization>
	<address>
	<postal>
	<street>Exora Business Park</street>
	<city>Bangalore</city>
	<region>KA</region>
	<code>560103</code>
	<country>India</country>
	</postal>
	<email>shraddha@juniper.net</email>
	</address>
	</author>
	<author initials="W." surname="Britto" fullname="William Britto A J">
	<organization>Juniper Networks Inc.</organization>
	<address>
	<postal>
	<street></street>
	<city></city>
	<region></region>
	<code></code>
	<country></country>
	</postal>
	<email>bwilliam@juniper.net</email>
	</address>
	</author>

	<author initials="R." surname="Shetty" fullname="Rajesh Shetty">
	<organization>Juniper Networks Inc.</organization>
	<address>
	<postal>
	<street></street>
	<city></city>
	<region></region>
	<code></code>
	<country></country>
	</postal>
	<email>mrajesh@juniper.net</email>
	</address>
	</author>

	<author initials="B." surname="Decraene" fullname="Bruno Decraene">
	<organization>Orange</organization>
	<address>
	<postal>
	<street></street>
	<city></city>
	<region></region>
	<code></code>
	<country></country>
	</postal>
	<email>bruno.decraene@orange.com</email>
	</address>
	</author>

	<author initials="P." surname="Psenak" fullname="Peter Psenak">
	<organization>Cisco Systems</organization>
	<address>
	<postal>
	<street></street>
	<city></city>
	<region></region>
	<code></code>
	<country></country>
	</postal>
	<email>ppsenak@cisco.com</email>
	</address>
	</author>


	<author initials="T." surname="Li" fullname="Tony Li">	<!DOCTYPE rfc [
	<organization>Juniper Networks Inc.</organization>	<!ENTITY nbsp " ">
	<address>	<!ENTITY zwsp "">
	<postal>	<!ENTITY nbhy "‑">
	<street></street>	<!ENTITY wj "⁠">
	<city></city>	]>
	<region></region>
	<code></code>
	<country></country>
	</postal>
	<email>tony.li@tony.li</email>
	</address>
	</author>


	<date year="2025"/>	<rfc xmlns:xi="http://www.w3.org/2001/XInclude" category="std" docName="draft-ie
	<area>Routing</area>	tf-lsr-flex-algo-bw-con-22" number="9843" consensus="true" ipr="trust200902" obs
	<workgroup>LSR</workgroup>	oletes="" updates="9350" submissionType="IETF" xml:lang="en" tocInclude="true" t
	<keyword>AS</keyword>	ocDepth="3" symRefs="true" sortRefs="true" version="3">
	<keyword>IGP</keyword>


	<abstract>	<front>
	<t>	<title abbrev="IGP Flex-Algorithms: Bandwidth, Delay, and Metrics">IGP Flexi
	Many networks configure the IGP link metric relative to the link capacity.	ble
	High bandwidth traffic gets routed as per the link capacity. Flexible	Algorithms: Bandwidth, Delay, Metrics, and Constraints</title>
	algorithms <xref target ='RFC9350'/>provide mechanisms to	<seriesInfo name="RFC" value="9843"/>
	create constraint based paths in an IGP.	<author initials="S." surname="Hegde" fullname="Shraddha Hegde">
	This draft documents a generic metric type and	<organization>Juniper Networks Inc.</organization>
	set of bandwidth related constraints to be used in Flexible Algorithms.	<address>
	</t>	<postal>
		<street>Exora Business Park</street>
		<city>Bangalore</city>
		<region>Karnataka</region>
		<code>560103</code>
		<country>India</country>
		</postal>
		<email>shraddha@juniper.net</email>
		</address>
		</author>
		<author initials="W." surname="Britto" fullname="William Britto">
		<organization>Juniper Networks Inc.</organization>
		<address>
		<email>bwilliam@juniper.net</email>
		</address>
		</author>
		<author initials="R." surname="Shetty" fullname="Rajesh Shetty">
		<organization>Juniper Networks Inc.</organization>
		<address>
		<email>mrajesh@juniper.net</email>
		</address>
		</author>
		<author initials="B." surname="Decraene" fullname="Bruno Decraene">
		<organization>Orange</organization>
		<address>
		<email>bruno.decraene@orange.com</email>
		</address>
		</author>
		<author initials="P." surname="Psenak" fullname="Peter Psenak">
		<organization>Cisco Systems</organization>
		<address>
		<email>ppsenak@cisco.com</email>
		</address>
		</author>
		<author initials="T." surname="Li" fullname="Tony Li">
		<organization>Juniper Networks Inc.</organization>
		<address>
		<email>tony.li@tony.li</email>
		</address>
		</author>
		<date year="2025" month="September"/>


	</abstract>	<area>RTG</area>
		<workgroup>lsr</workgroup>


	<note title="Requirements Language">	<keyword>AS</keyword>
	<t> The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",	<keyword>IGP</keyword>
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
	"OPTIONAL" in this document are to be interpreted as described in BCP
	14, <xref target ='RFC2119'/>, <xref target ='RFC8174'/> when, and only when
	,
	they appear in all capitals, as shown here.
	</t>
	</note>


	</front>	<abstract>
		<t>
		Many networks configure the IGP link metric relative to the link capacity, a
		nd high
		bandwidth traffic gets routed per the link capacity. Flexible
		Algorithms provide mechanisms to create constraint-based paths in an IGP.
		This specification documents a generic metric-type and a
		set of bandwidth-related constraints to be used in Flexible Algorithms.
		</t>
		<t>This document updates RFC 9350.</t>
		</abstract>


	<middle>	</front>
	<section title="Introduction" anchor='sec_introduction'>	<middle>
	<t> High bandwidth traffic such as residential Internet traffic and	<section anchor="sec_introduction" numbered="true" toc="default">
		<name>Introduction</name>
		<t> High bandwidth traffic such as residential Internet traffic and
	machine-to-machine elephant flows benefit from using high capacity	machine-to-machine elephant flows benefit from using high capacity
	links. Accordingly, many network operators define a link's metric	links. Accordingly, many network operators define a link's metric
	relative to its capacity to help direct traffic to higher bandwidth	relative to its capacity to help direct traffic to higher bandwidth
	links, but this is no guarantee that lower bandwidth links will be	links, but this is no guarantee that lower bandwidth links will be
	avoided, especially in failure scenarios. To ensure that elephant	avoided, especially in failure scenarios. To ensure that elephant
	flows are only placed on high capacity links, it would be useful to	flows are only placed on high capacity links, it would be useful to
	explicitly exclude the high throughput traffic from utilizing links	explicitly exclude the high throughput traffic from utilizing links

	below a certain capacity. Flex-Algorithm <xref target ='RFC9350'/>	below a certain capacity. Flex-Algorithm <xref target="RFC9350" format="defau lt"/>
	provides a mechanism to create constrained paths by defining	provides a mechanism to create constrained paths by defining
	a set of parameters consisting of	a set of parameters consisting of
	calculation-type, metric-type, and a set of constraints. In	calculation-type, metric-type, and a set of constraints. In

	this document, we define further extensions to Flex-Algorithm Definition (FAD ) that	this document, we define further extensions to the Flexible Algorithm Definit ion (FAD) that
	will allow operators additional control over their traffic flows,	will allow operators additional control over their traffic flows,
	especially with respect to bandwidth constraints. </t>	especially with respect to bandwidth constraints. </t>

		<t>Historically, IGPs have done path computation by minimizing the
	<t>Historically, IGPs have done path computation by minimizing the
	sum of the link metrics along the path from source to	sum of the link metrics along the path from source to
	destination. While the metric has been administratively defined,	destination. While the metric has been administratively defined,
	implementations have defaulted to a metric that is inversely	implementations have defaulted to a metric that is inversely
	proportional to link bandwidth. This has driven traffic to higher	proportional to link bandwidth. This has driven traffic to higher
	bandwidth links and has required manual metric manipulation to	bandwidth links and has required manual metric manipulation to
	achieve the desired loading of the network.</t>	achieve the desired loading of the network.</t>

		<t>Over time, with the addition of different traffic types, the need
	<t>Over time, with the addition of different traffic types, the need
	for alternate types of metrics has evolved. Flex-Algorithm	for alternate types of metrics has evolved. Flex-Algorithm
	already supports using the minimum link delay and the	already supports using the minimum link delay and the
	administratively assigned traffic-engineering metrics in path	administratively assigned traffic-engineering metrics in path
	computation. However, it is clear that additional metrics may be of	computation. However, it is clear that additional metrics may be of
	interest in different situations. A network operator may seek to	interest in different situations. A network operator may seek to
	minimize their operational costs and thus may want a metric that	minimize their operational costs and thus may want a metric that
	reflects the actual fiscal costs of using a link. Other traffic	reflects the actual fiscal costs of using a link. Other traffic
	may require low jitter, leading to an entirely different set of	may require low jitter, leading to an entirely different set of
	metrics. With Flex-Algorithm, all of these different metrics, and	metrics. With Flex-Algorithm, all of these different metrics, and
	more, could be used concurrently on the same network.</t>	more, could be used concurrently on the same network.</t>

		<t>In some circumstances, path computation constraints, such as
	<t>In some circumstances, path computation constraints, such as
	administrative groups, can be used to ensure that traffic avoids	administrative groups, can be used to ensure that traffic avoids
	particular portions of the network. These strict constraints are	particular portions of the network. These strict constraints are
	appropriate when there is an absolute requirement to avoid parts of	appropriate when there is an absolute requirement to avoid parts of

	the topology, even in failure conditions. If, however, the	the topology, even in failure conditions. However, if the
	requirement is less strict, then using a high metric in a portion	requirement is less strict, then using a high metric in a portion
	of the topology may be more appropriate. </t>	of the topology may be more appropriate. </t>

		<t>This document defines a family of generic metrics that can advertise
		various types of administratively assigned metrics. This document introduc
		es
		standard metric-types that have specific semantics and require
		standardization.
		This document also specifies user-defined metric-types where specifics are
		not defined so that administrators are free to assign semantics as
		they see fit.</t>


	<t>This document defines a family of generic metrics that can advertise	<t> <xref target="sec_fad_con" format="default"/> defines additional FAD <
	various types of administratively assigned metrics. This document proposes	xref target="RFC9350" format="default"/>
	standard metric-types which have specific semantics and require
	to be standardized.
	This document also specifies user defined metric-types where specifics are
	not defined, so that administrators are free to assign semantics as
	they see fit.</t>
	<t>In <xref target ='sec_bw_metric'/>, this document specifies a
	new bandwidth based metric
	type to be used with Flex-Algorithm and other applications.
	<xref target ='sec_fad_con'/> defines additional
	Flexible Algorithm Definition (FAD) <xref target ='RFC9350'/>
	constraints that allow the network	constraints that allow the network
	administrator to preclude the use of low bandwidth links or high	administrator to preclude the use of low bandwidth links or high

	delay links.</t>	delay links. <xref target="sec_bw_metric" format="default"/> specifies a new
	<t> <xref target ='sec_auto_metric'/>	bandwidth-based metric-type
		to be used with Flex-Algorithm and other applications.
		</t>
		<t> <xref target="sec_auto_metric" format="default"/>
	defines mechanisms to automatically calculate link metrics based on	defines mechanisms to automatically calculate link metrics based on
	the parameters defined in the FAD and the advertised Maximum Link Bandwidth	the parameters defined in the FAD and the advertised Maximum Link Bandwidth
	of each link. This is advantageous because administrators can change their	of each link. This is advantageous because administrators can change their
	criteria for metric assignment centrally, without individual	criteria for metric assignment centrally, without individual
	modification of each link metric throughout the network. The procedures	modification of each link metric throughout the network. The procedures
	described in this document are intended to assign a metric to a link based on	described in this document are intended to assign a metric to a link based on

	the total link capacity and they are not intended to update the metric based	the total link capacity, and they are not intended to update the metric based
	on actual traffic flow. Thus, the procedures described in this document are n ot a	on actual traffic flow. Thus, the procedures described in this document are n ot a

	replacement to the capability of a PCE <xref target ='RFC4655'/> which has a dynamic view of	replacement to the capability of a PCE <xref target="RFC4655" format="defaul t"/>, which has a dynamic view of
	the network and provides real-time bandwidth management or a distributed band width	the network and provides real-time bandwidth management or a distributed band width

	management protocol.</t>	management protocol.</t>


		<section anchor="req_lang" numbered="true" toc="default">
		<name>Requirements Language</name>
		<t>
		The key words "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>", "<bcp14>REQU
		IRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL
		NOT</bcp14>", "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>", "<bcp14>
		RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>",
		"<bcp14>MAY</bcp14>", and "<bcp14>OPTIONAL</bcp14>" in this document are to
		be interpreted as
		described in BCP 14 <xref target="RFC2119"/> <xref target="RFC8174"/>
		when, and only when, they appear in all capitals, as shown here.
		</t>
		</section>
	</section>	</section>


	<section title="Generic Metric Advertisement"	<section anchor="sec_generic_metric" numbered="true" toc="default">
	anchor='sec_generic_metric'>	<name>Generic Metric Advertisement</name>
	<t> IS-IS <xref target ='RFC1195'/>and OSPF <xref target ='RFC2328'/> advertise	<t> IS-IS <xref target="RFC1195" format="default"/> and OSPF <xref target=
		"RFC2328" format="default"/> advertise
	a metric for each link in their respective	a metric for each link in their respective

	link state advertisements. Multiple metric types are already supported.	link state advertisements. Multiple metric-types are already supported.
	Administratively assigned metrics are described in the original OSPF	Administratively assigned metrics are described in the original OSPF
	and IS-IS specifications. The Traffic Engineering Default Metric	and IS-IS specifications. The Traffic Engineering Default Metric

	is defined in <xref target ='RFC5305'/> and <xref target ='RFC3630'/>	is defined in <xref target="RFC5305" format="default"/> and <xref target="RFC363
	and the Min Unidirectional delay metric is defined in	0" format="default"/>,
	<xref target ='RFC8570'/> and <xref target ='RFC7471'/>.	and the Unidirectional Link Delay is defined in
		<xref target="RFC8570" format="default"/> and <xref target="RFC7471" format="def
		ault"/>.
	Other metrics, such as jitter, reliability, and fiscal cost may be	Other metrics, such as jitter, reliability, and fiscal cost may be
	helpful, depending on the traffic class. Rather than attempt to	helpful, depending on the traffic class. Rather than attempt to
	enumerate all possible metrics of interest, this document specifies	enumerate all possible metrics of interest, this document specifies
	a generic mechanism for advertising metrics. </t>	a generic mechanism for advertising metrics. </t>

	<t>
	Each generic metric advertisement is on a per-link and per-metric
	type basis. The metric advertisement consists of a metric type
	field and a value for the metric. The metric type field is
	assigned by the "IGP Metric-Type" IANA registry. Metric types
	0-127 are standard metric types as assigned by IANA. This document
	further specifies a user-defined metric type space of metric types
	128-255. These are user defined and can be assigned by an operator
	for local use.
	</t>
	<t>Implementations MUST support sending and receiving generic metric
	sub-TLV in Application Specific Link Attributes (ASLA)encodings as
	well as in the TLV 22/extended link LSA/TE-LSAs.
	The usage of a generic metric by an individual application is subject to the sa
	me
	rules that apply to other link attributes as defined in <xref target ='RFC3630'
	/>,
	<xref target ='RFC5305'/>, <xref target ='RFC9479'/>,
	<xref target ='RFC9492'/> and <xref target ='RFC9350'/>.</t>


	<section title="IS-IS Generic Metric Sub-TLV"	<t>
	anchor='sec_isis_gen_metric'>	Each generic metric advertisement is on a per-link and per-metric-type
	<t>The IS-IS Generic Metric sub-TLV specifies the link metric for a given	basis. The metric advertisement consists of a metric-type
	metric type. Typically, this metric is assigned by a	field and a value for the metric. The metric-type field has been
		assigned in the "IGP Metric-Type" IANA registry. Metric-types
		0-127 are standard metric-types as assigned by IANA. This document
		further specifies a user-defined metric-type space of metric-types
		128-255. They can be assigned by an operator for local use.
		</t>

		<t>Implementations <bcp14>MUST</bcp14> support sending and receiving a Gen
		eric Metric
		sub-TLV in Application-Specific Link Attributes (ASLA) encodings as
		well as in TLV 22 and Extended Link Opaque Link State Advertisements (LSAs) <xr
		ef target="RFC7684" format="default"/> and TE-LSAs.
		The usage of a generic metric by an individual application is subject to the sa
		me
		rules that apply to other link attributes as defined in <xref target="RFC3630"
		format="default"/>,
		<xref target="RFC5305" format="default"/>, <xref target="RFC9479" format="defau
		lt"/>,
		<xref target="RFC9492" format="default"/>, and <xref target="RFC9350" format="d
		efault"/>.</t>
		<section anchor="sec_isis_gen_metric" numbered="true" toc="default">
		<name>IS-IS Generic Metric Sub-TLV</name>
		<t>The IS-IS Generic Metric sub-TLV specifies the link metric for a give
		n
		metric-type. Typically, this metric is assigned by a
	network administrator.	network administrator.
	The Generic Metric sub-TLV is advertised in the TLVs/sub-TLVs below:</t>	The Generic Metric sub-TLV is advertised in the TLVs/sub-TLVs below:</t>

		<ol spacing="normal" type="a">
	<t><list>	<li>TLV 22 (Extended IS reachability) <xref target="RFC5305"
	<t>a. TLV-22 (Extended IS reachability) <xref target ='RFC5305'/></t>	format="default"/></li>
		<li>TLV 222 (MT-ISN) <xref target="RFC5120" format="default"/></li>
	<t>b. TLV-222 (MT-ISN) <xref target ='RFC5120'/></t>	<li>TLV 23 (IS Neighbor Attribute) <xref target="RFC5311"
		format="default"/></li>
	<t>c. TLV-23 (IS Neighbor Attribute) <xref target ='RFC5311'/></t>	<li>TLV 223 (MT IS Neighbor Attribute) <xref target="RFC5311"
		format="default"/></li>
	<t>d. TLV-223 (MT IS Neighbor Attribute) <xref target ='RFC5311'/> </t>	<li>TLV 141 (Inter-AS Reachability Information) <xref
		target="RFC9346" format="default"/></li>
	<t>e. TLV-141 (inter-AS reachability information) <xref target ='RFC9346'/	<li>sub-TLV 16 (Application-Specific Link Attributes (ASLA)) of TLVs
	></t>	22/222/23/223/141 <xref target="RFC9479" format="default"/></li>
		<li>TLV 25 (L2 Bundle Member Attributes) <xref target="RFC8668"
	<t>f. sub-TLV 16 (Application-Specific Link Attributes (ASLA)) of	format="default"/>. Marked as "y(s)" (shareable among bundle
	TLV 22/222/23/223/141 <xref target ='RFC9479'/></t>	members).</li>
		</ol>
	<t>g. TLV 25 (L2 Bundle Member Attributes) <xref target ='RFC8668'/>	<figure anchor="isis_gen_metric_sub_tlv">
	Marked as "y(s)" (shareable among bundle members)</t>	<name>IS-IS Generic Metric Sub-TLV</name>
		<artwork name="" type="" align="left" alt=""><![CDATA[
	</list></t>
	<t>The Generic Metric sub-TLV, type TBD1 (IANA), and is six
	octets in length.
	<figure anchor="isis_gen_metric_sub_tlv"
	title="IS-IS Generic Metric Sub-TLV">
	<artwork>
	0 1 2 3	0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Type \| Length \| metric-type \|	\| Type \| Length \| metric-type \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Value \|	\| Value \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

		]]></artwork>
	Type (1 octet):	</figure>
	An 8-bit field assigned by IANA (To Be Determined as TBD1).	<t keepWithNext="true">
	This value uniquely identifies the Generic Metric TLV.	where:

	Length (1 octet):
	An 8-bit field indicating the total length, in octets,
	of the subsequent fields. For this TLV, the Length is set to 4.

	Metric-Type (1 octet):
	An 8-bit field specifying the type of metric.
	The value is taken from the "IGP Metric-Type"
	registry maintained by IANA. The metric type may
	be any value which is indicated as allowed
	in the generic metric sub-TLV by the
	IGP Metric-Type Registry.

	Value (3 octets):
	A 24-bit unsigned integer representing the metric value.
	The valid range is from 0 to 16,777,215 (0xFFFFFF).

	</artwork>
	</figure>
	</t>	</t>

	<t>
	The Generic Metric sub-TLV MAY be advertised multiple times.	<dl spacing="normal" newline="true">
	For a particular metric type,	<dt>Type (1 octet):</dt>
	the Generic Metric sub-TLV MUST be advertised only once for a link	<dd>An 8-bit field assigned by IANA (17). This value
	when advertised in TLV 22, 222, 23, 223 and 141.	uniquely identifies the Generic Metric TLV.</dd>
	When Generic metric sub-TLV is advertised in ASLA,	<dt>Length (1 octet):</dt>
	each metric type MUST be advertised only once per-application for a link.	<dd>An 8-bit field indicating the total length, in octets, of the subsequent
		fields. For this TLV, the Length is set to 4.</dd>
		<dt>Metric-Type (1 octet):</dt>
		<dd>An 8-bit field specifying the type of metric. The value is taken from
		the "IGP Metric-Type" registry maintained by IANA. The metric-type may be
		any value that is indicated as allowed in the Generic Metric sub-TLV by the
		"IGP Metric-Type" registry.</dd>
		<dt>Value (3 octets):</dt>
		<dd>A 24-bit unsigned integer representing the metric value. The valid
		range is from 0 to 16,777,215 (0xFFFFFF).</dd>
		</dl>
		<t>
		The Generic Metric sub-TLV <bcp14>MAY</bcp14> be advertised multiple times.
		For a particular metric-type,
		the Generic Metric sub-TLV <bcp14>MUST</bcp14> be advertised only once for a
		link
		when advertised in TLVs 22, 222, 23, 223, and 141.
		When the Generic Metric sub-TLV is advertised in ASLA,
		each metric-type <bcp14>MUST</bcp14> be advertised only once per-application
		for a link.
	If there are multiple Generic Metric sub-TLVs advertised for a link	If there are multiple Generic Metric sub-TLVs advertised for a link

	for the same metric type (and same application in case of ASLA)	for the same metric-type (and the same application in case of ASLA)
	in one or more received LSPDUs, advertisement in the lowest numbered fragmen	in one or more received Link State Protocol Data Units (LSPDUs), advertiseme
	t	nt in the lowest-numbered fragment
	MUST be used and the subsequent instances MUST be ignored.	<bcp14>MUST</bcp14> be used, and the subsequent instances <bcp14>MUST</bcp14
	</t>	> be ignored.
	<t>For a link, if the metric type corresponds to a metric type for	</t>
	which legacy advertisement mechanisms exist (e.g., the IGP metric,	<t>For a link, if the metric-type corresponds to a metric-type for
	the Minimum Unidirectional Link Delay, or the	which legacy advertisement mechanisms exist (e.g., the IGP Metric,
	Traffic Engineering Default Metric), the legacy metric types MUST	the Min Unidirectional Link Delay, or the
		Traffic Engineering Default Metric), the legacy metric-types <bcp14>MUST</bc
		p14>
	be utilized from the existing TLV or sub-TLVs. If a Generic Metric	be utilized from the existing TLV or sub-TLVs. If a Generic Metric

	advertises a legacy metric, it MUST be ignored.	advertises a legacy metric, it <bcp14>MUST</bcp14> be ignored.
	.	</t>
	</t>	<t>A metric value of
	<t>A metric value of	0xFFFFFF is considered a maximum link metric, and a link having
	0xFFFFFF is considered as maximum link metric and a link having	this metric value <bcp14>MUST</bcp14> be used during Flex-Algorithm calculati
	this metric value MUST be used during Flex-algorithm calculations	ons
	as a last resort link as described in sec 15.3 of <xref target ='RFC9350'/>.	as a last resort link as described in <xref section="15.3" target="RFC9350" f
	A link can be made unusable by Flex-algorithm by leaving out Generic metric	ormat="default"/>.
	advertisement of the particular metric-type that the Flex-algorithm	A link can be made unusable by Flex-Algorithm by leaving out Generic Metric
	uses as described in <xref target ='RFC9350'/>.	advertisement of the particular metric-type that the Flex-Algorithm
	</t>	uses, as described in <xref target="RFC9350" format="default"/>.
		</t>
	<t> During the router maintenance activity, the Generic Metric for	<t> During the router maintenance activity, the Generic Metric for
	all the links on the node MAY be set to a maximum value of	all the links on the node <bcp14>MAY</bcp14> be set to a maximum value of
	16,777,215 (0xFFFFFF), as it is the maximum usable link metric for the	16,777,215 (0xFFFFFF), as it is the maximum usable link metric for the

	Flex-algorithm calculations.</t>	Flex-Algorithm calculations.</t>
	</section>	</section>
		<section anchor="sec_ospf_gen_metric" numbered="true" toc="default">
	<section title="OSPF Generic Metric Sub-TLV"	<name>OSPF Generic Metric Sub-TLV</name>
	anchor='sec_ospf_gen_metric'>	<t>
	<t>
	The OSPF Generic Metric sub-TLV specifies the link metric for a given	The OSPF Generic Metric sub-TLV specifies the link metric for a given

	metric type. Typically, this metric is assigned by a	metric-type. Typically, this metric is assigned by a
	network administrator.	network administrator.
	The Generic Metric sub-TLV is advertised in the TLVs below:</t>	The Generic Metric sub-TLV is advertised in the TLVs below:</t>

		<ol type="a" spacing="normal">


	<t><list>	<li>sub-TLV of TE Link TLV (type 2) of OSPF TE LSA <xref target="RFC36
	<t>a. sub-TLV of TE Link TLV (2) of OSPF TE LSA <xref target ='RFC3630'	30" format="default"/>.</li>
	/>.</t>	<li>sub-TLV of TE Link TLV (type 2) of OSPFv2 Inter-AS-TE-v2 LSA <xref
	<t>b. sub-TLV of TE Link TLV (2) of OSPFv2 Inter-AS-TE-v2 LSA <xref tar	target="RFC5392" format="default"/>.</li>
	get ='RFC5392'/>.</t>	<li>sub-TLV of TE Link TLV (type 2) of OSPFv3 Intra-Area-TE-LSA <xref
	<t>c. sub-TLV of TE Link TLV (2) of OSPFv3 Intra-Area-TE-LSA <xref targ	target="RFC5329" format="default"/>.</li>
	et ='RFC5329'/>.</t>	<li>sub-TLV of TE Link TLV (type 2) of OSPFv3 Inter-AS-TE-v3 LSA <xref
	<t>d. sub-TLV of TE Link TLV (2) of OSPFv3 Inter-AS-TE-v3 LSA <xref tar	target="RFC5392" format="default"/>.</li>
	get ='RFC5392'/>.</t>	<li>sub-TLV of Application-Specific Link Attributes (ASLA) sub-TLV <xr
	<t>e. sub-TLV of Application-Specific Link Attributes (ASLA) sub-TLV <x	ef target="RFC9492" format="default"/>
	ref target ='RFC9492'/>	of the OSPFv2 Extended Link TLV <xref target="RFC7684" format="defau
	of the OSPFv2 Extended Link TLV <xref target ='RFC7684'/>.</t>	lt"/>.</li>
	<t>f. sub-TLV of Application-Specific Link Attributes (ASLA) sub-TLV <x	<li>sub-TLV of Application-Specific Link Attributes (ASLA) sub-TLV <xr
	ref target ='RFC9492'/>	ef target="RFC9492" format="default"/>
	of the OSPFv3 Router-Link TLV <xref target ='RFC8362'/>.</t>	of the OSPFv3 Router-Link TLV <xref target="RFC8362" format="default
	<t>g. sub-TLV of the OSPFv2 L2 Bundle Member Attributes sub-TLV <xref targ	"/>.</li>
	et ='RFC9356'/>.</t>	<li>sub-TLV of the OSPFv2 L2 Bundle Member Attributes sub-TLV <xref ta
	<t>h. sub-TLV of the OSPFv3 L2 Bundle Member Attributes sub-TLV <xref targ	rget="RFC9356" format="default"/>.</li>
	et ='RFC9356'/>.</t>	<li>sub-TLV of the OSPFv3 L2 Bundle Member Attributes sub-TLV <xref ta
		rget="RFC9356" format="default"/>.</li>
	</list></t>	</ol>

	<t>The Generic Metric sub-TLV, type TBD21/TBD22/TB23 (IANA), and is eight
	octets in length.


	<figure anchor="ospf_gen_metric_sub_tlv"	<t>The Generic Metric sub-TLV, types 25/36/34, is 8 octets in length.
	title="OSPF Generic Metric Sub-TLV ">	</t>
	<artwork>	<figure anchor="ospf_gen_metric_sub_tlv">
		<name>OSPF Generic Metric Sub-TLV</name>
		<artwork name="" type="" align="left" alt=""><![CDATA[
	0 1 2 3	0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Type \| Length \|	\| Type \| Length \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| metric-type \| Reserved (MBZ) \|	\| metric-type \| Reserved (MBZ) \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Value \|	\| Value \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

		]]></artwork>
		</figure>


	Type (2 octets):	<t>
	A 16-bit field assigned by IANA (To Be Determined as TBD21/TBD22/TBD23).	where:
	This value uniquely identifies the Generic Metric TLV.	</t>
		<dl spacing="normal" newline="true">
	Length (2 octets):	<dt>Type (2 octets):</dt>
	A 16-bit field indicating the total length, in octets,	<dd>A 16-bit field assigned by IANA (25/36/34).
	of the subsequent fields. For this TLV, the Length is set to 8.	This value uniquely identifies the Generic Metric TLV.</dd>
		<dt>Length (2 octets):</dt>
	Metric-Type (1 octet):	<dd>A 16-bit field indicating the total length, in octets, of the subsequent
	An 8-bit field specifying the type of metric.	fields. For this TLV, the Length is set to 8.</dd>
	The value is taken from the "IGP Metric-Type"	<dt>Metric-Type (1 octet):</dt>
	registry maintained by IANA. The metric type	<dd>An 8-bit field specifying the type of metric. The value is taken from
	may be any value which is indicated as allowed	the "IGP Metric-Type" registry maintained by IANA. The metric-type may be
	in the generic metric sub-TLV by the	any value that is indicated as allowed in the Generic Metric sub-TLV by the
	IGP Metric-Type Registry.	"IGP Metric-Type" registry.</dd>
		<dt>Reserved (3 octets):</dt>
	Reserved (3 octets):	<dd><bcp14>MUST</bcp14> set to zero by the sender and <bcp14>MUST</bcp14> be i
	Must set to zero by sender and	gnored by the receiver.</dd>
	must be ignored by receiver.	<dt>Value (4 octets):</dt>
		<dd>A 32-bit unsigned integer representing the metric value.
	Value (4 octets):	The valid
	A 32-bit unsigned integer representing the metric value.	range is from 0 to 4,294,967,295 (0xFFFFFFFF).</dd>
	The valid range is from 0 to 4,294,967,295(0xFFFFFFFF).	</dl>


	</artwork>	<t>The Generic Metric sub-TLV <bcp14>MAY</bcp14> be advertised multiple times.
	</figure>	For a particular metric-type, the Generic Metric sub-TLV <bcp14>MUST</bcp14>
	<t>The Generic Metric sub-TLV MAY be advertised multiple times.	be advertised only once for a link when advertised as (a) through (d) above.
	For a particular metric type, the Generic Metric sub-TLV MUST be	When the Generic Metric sub-TLV is advertised as a sub-TLV of ASLA, it
	advertised only once for a link when advertised as (a) through (d) above.	<bcp14>MUST</bcp14> be advertised only once per application for a link. If
	When Generic Metric sub-TLV is advertised as sub-TLV of	there are multiple Generic Metric sub-TLVs advertised for a link for the same
	ASLA, it MUST be advertised only once per-application for a link.	metric-type (and the same application in case of ASLA) in one or more received
	If there are multiple Generic Metric sub-TLVs advertised for	LSAs, advertisement in the lowest-numbered LSA <bcp14>MUST</bcp14> be used, and
	a link for the same metric type (and same application in case of ASLA)	the subsequent instances <bcp14>MUST</bcp14> be ignored.</t>
	in one or more received LSAs, advertisement in the lowest numbered	<t>For a link, if the metric-type corresponds to a metric-type for
	LSA MUST be used and the subsequent instances MUST be ignored.</t>	which legacy advertisement mechanisms exist (e.g., the IGP Metric,
	<t>For a link, if the metric type corresponds to a metric type for	the Min Unidirectional Link Delay, or the Traffic Engineering
	which legacy advertisement mechanisms exist (e.g., the IGP metric,	Default Metric), the legacy metric-types <bcp14>MUST</bcp14> be utilized
	the Minimum Unidirectional Link Delay, or the Traffic Engineering	from
	Default Metric), the legacy metric types MUST be utilized from
	the existing TLV or sub-TLVs. If a Generic Metric advertises a	the existing TLV or sub-TLVs. If a Generic Metric advertises a

	legacy metric, it MUST be ignored.	legacy metric, it <bcp14>MUST</bcp14> be ignored.
	</t>	</t>

	<t>A metric value of	<t>A metric value of
	0xFFFFFFFF is considered as maximum link metric and a link having	0xFFFFFFFF is considered a maximum link metric, and a link having
	this metric value MUST be used during Flex-algorithm calculations	this metric value <bcp14>MUST</bcp14> be used during Flex-Algorithm calculati
	as a last resort link as described in sec 15.3 of <xref target ='RFC9350'/>.<	ons
	/t>	as a last resort link, as described in <xref section="15.3" target="RFC9350"
	</t>	format="default"/>.</t>
	<t>A link can be made unusable by Flex-algorithm by leaving out Generic m	<t>A link can be made unusable by Flex-Algorithm by leaving out Generic
	etric	Metric
	advertisement of the particular metric-type that the Flex-algorithm	advertisement of the particular metric-type that the Flex-Algorithm
	uses as described in <xref target ='RFC9350'/>.</t>	uses, as described in <xref target="RFC9350" format="default"/>.</t>
	<t> During the router maintenance activity, the Generic Metric for
	all the links on the node MAY be set to a maximum value of
	4,294,967,295 ((0xFFFFFFFF), as it is the maximum usable link metric for the
	Flex-algorithm calculations.</t>

	</section>


	<section	<t> During the router maintenance activity, the Generic Metric for
	title="Generic Metric applicability to Flexible Algorithms Multi-domain/Multi-ar	all the links on the node <bcp14>MAY</bcp14> be set to a maximum value of
	ea networks "	4,294,967,295 (0xFFFFFFFF), as it is the maximum usable link metric for the
	anchor='sec_multi_area'>	Flex-Algorithm calculations.</t>
	<t>Generic Metric can be used by Flex-Algorithms	</section>
	by specifying the metric type in the	<section anchor="sec_multi_area" numbered="true" toc="default">
	Flexible Algorithm Definitions. When Flex-Algorithms is used in a multi-area net	<name>Generic Metric Applicability to Flexible Algorithm Multi-Domain/Mu
	work,	lti-Area Networks</name>
	<xref target ='RFC9350'/> defines the Flexible Algorithm Prefix Metric (FAPM)	<t>Generic Metric can be used by Flex-Algorithm
		by specifying the metric-type in the
		Flexible Algorithm Definitions. When Flex-Algorithm is used in a multi-area netw
		ork,
		<xref target="RFC9350" format="default"/> defines the Flexible Algorithm Prefix
		Metric (FAPM)
	sub-TLV that carries	sub-TLV that carries
	the Flexible-Algorithm-specific metric. Metrics carried in FAPM will be equal	the Flexible-Algorithm-specific metric. Metrics carried in FAPM will be equal
	to the metric to reach the prefix for that Flex-Algorithm in its	to the metric to reach the prefix for that Flex-Algorithm in its

	source area or domain (source area from the ABR perspective). When Flex-Algorith	source area or domain (source area from the Area Border Router (ABR) perspective
	m uses	). When Flex-Algorithm uses
	Generic metric, the same procedures as described in section 13 of	Generic Metric, the same procedures as described in
	<xref target ='RFC9350'/>	<xref target="RFC9350" sectionFormat="of" section="13"/>
	are used to send and process FAPM sub-TLV.</t>	are used to send and process the FAPM sub-TLV.</t>
	</section>	</section>
	</section>	</section>
		<section anchor="sec_fad_con" numbered="true" toc="default">
	<section title=" FAD constraint Sub-TLVs" anchor='sec_fad_con'>	<name>FAD Constraint Sub-TLVs</name>
		<t>
	<t>

	Large high throughput flows are referred to as "elephant flows".	Large high throughput flows are referred to as "elephant flows".
	Directing an elephant flow	Directing an elephant flow
	down a low-bandwidth link might congest the link and cause other	down a low-bandwidth link might congest the link and cause other
	critical application traffic flowing on the link to drop. Thus, in the	critical application traffic flowing on the link to drop. Thus, in the
	context of Flex-Algorithm, it would be useful to be able to	context of Flex-Algorithm, it would be useful to be able to
	constrain the topology to only those links capable of supporting a	constrain the topology to only those links capable of supporting a

	minimum amount of bandwidth.</t>	minimum amount of bandwidth.</t>


	<t>If the capacity of a link is constant, this can already be achieved	<t>If the capacity of a low bandwidth link is constant, constraining the t
	through the use of administrative groups. However, when a layer-3	opology to avoid those links can already be achieved
	link is actually a collection of layer-2 links (LAG/layer-2	through the use of administrative groups. However, when a Layer 3
		link is actually a collection of Layer 2 links (Link Aggregation Group (LAG)
		/ Layer 2
	Bundle), the link bandwidth will vary based on the set of active	Bundle), the link bandwidth will vary based on the set of active
	constituent links. This could be automated by having an	constituent links. This could be automated by having an
	implementation vary the advertised administrative groups based on	implementation vary the advertised administrative groups based on
	bandwidth, but this seems unnecessarily complex and expressing this	bandwidth, but this seems unnecessarily complex and expressing this
	requirement as a direct constraint on the topology seems	requirement as a direct constraint on the topology seems
	simpler. This is also advantageous if the minimum required	simpler. This is also advantageous if the minimum required
	bandwidth changes, as this constraint would provide a single	bandwidth changes, as this constraint would provide a single
	centralized, coordinated point of control.</t>	centralized, coordinated point of control.</t>

		<t>To satisfy this requirement, this document defines an
	<t>To satisfy this requirement, this document defines an
	Exclude Minimum Bandwidth	Exclude Minimum Bandwidth
	constraint. When this constraint is advertised in a FAD,	constraint. When this constraint is advertised in a FAD,
	a link will be pruned from the Flex-Algorithm topology if the	a link will be pruned from the Flex-Algorithm topology if the

	link's advertised Maximum Link Bandwidth is below the advertised	link's advertised maximum link bandwidth value is below the FAD advertised
	Minimum Bandwidth value.</t>	minimum bandwidth value.</t>
		<t>Similarly, this document defines an Exclude Maximum Link Delay
	<t>Similarly, this document defines an Exclude Maximum Link Delay
	constraint. Applications, such as High-Frequency Trading are sensitive	constraint. Applications, such as High-Frequency Trading are sensitive
	to link delays and may perform poorly in networks prone to delay	to link delays and may perform poorly in networks prone to delay
	variability, such as those with transparent Layer 2 link	variability, such as those with transparent Layer 2 link

	recovery mechanisms or satellite links.".	recovery mechanisms or satellite links.
	Mechanisms already exist to measure the link delay dynamically and	Mechanisms already exist to measure the link delay dynamically and
	advertise it in the IGP. Networks that employ dynamic link-delay	advertise it in the IGP. Networks that employ dynamic link-delay
	measurement, may want to exclude links that have a delay over a	measurement, may want to exclude links that have a delay over a
	given threshold.</t>	given threshold.</t>

		<section anchor="sec_isis" numbered="true" toc="default">
		<name>IS-IS FAD Constraint Sub-TLVs</name>
		<section anchor="sec_isis_bw_exclusion" numbered="true" toc="default">
		<name>IS-IS Exclude Minimum Bandwidth Sub-TLV</name>
		<t>


	<section title="IS-IS FAD constraint Sub-TLVs" anchor='sec_isis'>	IS-IS Flex-Algorithm Exclude Minimum Bandwidth (FAEMB) sub-TLV is a
	<section title="IS-IS Exclude Minimum Bandwidth sub-TLV" anchor='sec_isis_bw_exc
	lusion'>
	<t>

	IS-IS Flex-Algorithm Exclude Minimum Bandwidth sub-TLV (FAEMB) is a
	sub-TLV of the IS-IS FAD sub-TLV. It has the following format:	sub-TLV of the IS-IS FAD sub-TLV. It has the following format:


	<figure anchor="isis_faemb_sub_tlv" title="IS-IS FAEMB Sub-TLV">	</t>
	<artwork>	<figure anchor="isis_faemb_sub_tlv">
		<name>IS-IS FAEMB Sub-TLV</name>
		<artwork name="" type="" align="left" alt=""><![CDATA[
	0 1 2 3	0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Type \| Length \|	\| Type \| Length \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Min Bandwidth \|	\| Min Bandwidth \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

	where:	]]></artwork>
		</figure>
	Type (1 octet):
	An 8-bit field assigned by IANA (To Be Determined as TBD3).
	This value uniquely identifies the FAEMB sub-TLV.

	Length (1 octet):
	An 8-bit field indicating the total length, in octets,
	of the subsequent fields. For this sub-TLV, the Length is set to 4.


	Min Bandwidth (4 octets):	<t>where:</t>
	A 32-bit field specifying the link bandwidth encoded in IEEE	<dl spacing="normal" newline="true">
	floating point format (32 bits)[IEEE754-2019].	<dt>Type (1 octet):</dt>
	The units are bytes-per-second.	<dd>An 8-bit field assigned by IANA (6). This value
		uniquely identifies the FAEMB sub-TLV.</dd>
		<dt>Length (1 octet):</dt>
		<dd>An 8-bit field indicating the total length, in octets, of the subsequent
		fields. For this sub-TLV, the Length is set to 4.</dd>
		<dt>Min Bandwidth (4 octets):</dt>
		<dd>A 32-bit field specifying the link bandwidth encoded in IEEE floating
		point format (32 bits) <xref target="IEEE754-2019"/>. The units are bytes per
		second.</dd>
		</dl>


	</artwork>	<t>The FAEMB sub-TLV <bcp14>MUST</bcp14> appear once at most in the FA
	</figure>	D sub-TLV.
	</t>	If it appears more than once, the IS-IS FAD sub-TLV <bcp14>MUST</bcp14> be
	<t>The FAEMB sub-TLV MUST appear at most once in the FAD sub-TLV.
	If it appears more than once, the IS-IS FAD sub-TLV MUST be
	ignored by the receiver. </t>	ignored by the receiver. </t>

		<t>The minimum bandwidth value advertised in the FAEMB sub-TLV <bcp14>
	<t>The Minimum bandwidth advertised in FAEMB sub-TLV MUST be compared with	MUST</bcp14> be compared with
	Maximum Link Bandwidth advertised in sub-sub-TLV 9 of ASLA sub-TLV <xref targ	maximum link bandwidth value advertised in sub-sub-TLV 9 of the ASLA sub-TLV
	et ='RFC9479'/>.	<xref target="RFC9479" format="default"/>.
	If L-Flag is set in the ASLA sub-TLV, the Minimum bandwidth advertised in FAE	If the L-flag is set in the ASLA sub-TLV, the minimum bandwidth value adverti
	MB	sed in the FAEMB
	sub-TLV MUST be compared with Maximum Link Bandwidth as	sub-TLV <bcp14>MUST</bcp14> be compared with the maximum link bandwidth value
	advertised in the sub-TLV 9 of the TLV	as
	22/222/23/223/141 <xref target ='RFC5305'/> as defined in <xref target ='RFC9	advertised in the sub-TLV 9 of the TLVs
	479'/>	22/222/23/223/141 <xref target="RFC5305" format="default"/>, as defined in <x
	Section 4.2. </t>	ref target="RFC9479" sectionFormat="of" section="4.2"/>. </t>
		<t>If the maximum link bandwidth value is lower than the minimum
	<t>If the Maximum Link Bandwidth is lower than the Minimum	link bandwidth value advertised in the FAEMB sub-TLV,
	link bandwidth advertised in FAEMB sub-TLV,	the link <bcp14>MUST</bcp14> be excluded from the Flex-Algorithm topology.
	the link MUST be excluded from the Flex-Algorithm topology.

	If a link does not have the Maximum Link Bandwidth advertised but the	If a link does not have the Maximum Link Bandwidth advertised but the

	FAD contains this sub-TLV, then that link	FAD contains the FAEMB sub-TLV, then that link
	MUST NOT be excluded from the topology based on the Minimum	<bcp14>MUST NOT</bcp14> be excluded from the topology based on the Minimum
	Bandwidth constraint.	Bandwidth constraint.

	</t>	</t>
	</section>	</section>
	<section title="IS-IS Exclude Maximum Delay Sub-TLV"	<section anchor="sec_isis_delay_exclusion" numbered="true" toc="default"
	anchor='sec_isis_delay_exclusion'>	>
	<t>	<name>IS-IS Exclude Maximum Delay Sub-TLV</name>
		<t>


	IS-IS Flex-Algorithm Exclude Maximum Delay sub-TLV (FAEMD) is a	IS-IS Flex-Algorithm Exclude Maximum Delay (FAEMD) sub-TLV is a
	sub-TLV of the IS-IS FAD sub-TLV. It has the following format.	sub-TLV of the IS-IS FAD sub-TLV. It has the following format:


	<figure anchor="isis_faemd_sub_tlv" title="IS-IS FAEMD Sub-TLV">	</t>
	<artwork>	<figure anchor="isis_faemd_sub_tlv">
		<name>IS-IS FAEMD Sub-TLV</name>
		<artwork name="" type="" align="left" alt=""><![CDATA[
	0 1 2 3	0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Type \| Length \|	\| Type \| Length \|

	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Max Link Delay \|	\| Max Link Delay \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	where:	]]></artwork>
		</figure>
	Type (1 octet):	<t>where:</t>
	An 8-bit field assigned by IANA (To Be Determined as TBD4).	<dl spacing="normal" newline="true">
	This value uniquely identifies the FAEMD sub-TLV.	<dt>Type (1 octet):</dt>
		<dd>An 8-bit field assigned by IANA (7). This value
	Length (1 octet):	uniquely identifies the FAEMD sub-TLV.</dd>
	An 8-bit field indicating the total length, in octets,	<dt>Length (1 octet):</dt>
	of the subsequent fields. For this sub-TLV, the Length is set to 3.	<dd>An 8-bit field indicating the total length, in octets, of the subsequent
		fields. For this sub-TLV, the Length is set to 3.</dd>
	Max link delay (3 octets):	<dt>Max Link Delay (3 octets):</dt>
	A 24-bit field specifying the Maximum link delay in microseconds.	<dd>A 24-bit field specifying the Maximum link delay in microseconds.</dd>
		</dl>
	</artwork>
	</figure>
	</t>
	<t>The FAEMD sub-TLV MUST appear only once in the FAD sub-TLV.
	If it appears more than once, the IS-IS FAD sub-TLV MUST be
	ignored by the receiver.</t>

	<t>The Maximum link delay advertised in FAEMD sub-TLV MUST be compared with
	Min Unidirectional Link Delay advertised in sub-sub-TLV 34 of ASLA sub-TLV <x
	ref target ='RFC9479'/>.
	If the L-Flag is set in the ASLA sub-TLV, the Maximum link delay advertised i
	n FAEMD
	sub-TLV MUST be compared with Min Unidirectional Link Delay as
	advertised by the sub-TLV 34 of the TLV
	22/222/23/223/141 <xref target ='RFC8570'/> as defined in <xref target ='RFC9
	479'/>
	Section 4.2. </t>


	<t>If the Min Unidirectional Link Delay value is higher than the	<t>The FAEMD sub-TLV <bcp14>MUST</bcp14> appear only once in the FAD sub-TLV.
	Maximum link delay advertised in FAEMD sub-TLV, the link MUST be	If it appears more than once, the IS-IS FAD sub-TLV <bcp14>MUST</bcp14> be
		ignored by the receiver.</t>
		<t>The maximum link delay value advertised in the FAEMD sub-TLV <bcp14
		>MUST</bcp14> be compared with
		Min Unidirectional Link Delay advertised in sub-sub-TLV 34 of the ASLA sub-TL
		V <xref target="RFC9479" format="default"/>.
		If the L-flag is set in the ASLA sub-TLV, the maximum link delay value advert
		ised in the FAEMD
		sub-TLV <bcp14>MUST</bcp14> be compared with Min Unidirectional Link Delay as
		advertised by the sub-TLV 34 of the TLVs
		22/222/23/223/141 <xref target="RFC8570" format="default"/>, as defined in <x
		ref target="RFC9479" sectionFormat="of" section="4.2"/>. </t>
		<t>If the Min Unidirectional Link Delay value is higher than the
		Maximum Link Delay advertised in the FAEMD sub-TLV, the link <bcp14>MUST</bcp
		14> be
	excluded from the Flex-Algorithm topology.	excluded from the Flex-Algorithm topology.

	If a link does not have the Min Unidirectional Link Delay advertised but	If a link does not have the Min Unidirectional Link Delay advertised but

	the FAD contains this sub-TLV, then that link MUST NOT be	the FAD contains the FAEMD sub-TLV, then that link <bcp14>MUST NOT</bcp14> be
	excluded from the topology based on the Maximum Delay constraint.	excluded from the topology based on the Maximum Delay constraint.

	</t>	</t>
	</section>	</section>
	</section>	</section>
		<section anchor="sec_ospf" numbered="true" toc="default">
	<section title="OSPF FAD constraint Sub-TLVs" anchor='sec_ospf'>	<name>OSPF FAD Constraint Sub-TLVs</name>
		<section anchor="sec_ospf_bw_exclusion" numbered="true" toc="default">
	<section title="OSPF Exclude Minimum Bandwidth Sub-TLV"	<name>OSPF Exclude Minimum Bandwidth Sub-TLV</name>
	anchor='sec_ospf_bw_exclusion'>	<t>
	<t>


	OSPF Flex-Algorithm Exclude Minimum Bandwidth sub-TLV (FAEMB) is a	OSPF Flex-Algorithm Exclude Minimum Bandwidth (FAEMB) sub-TLV is a
	sub-TLV of the OSPF FAD TLV. It has the following format:	sub-TLV of the OSPF FAD TLV. It has the following format:


	<figure anchor="ospf_faemb_sub_tlv" title="OSPF FAEMB Sub-TLV">	</t>
	<artwork>	<figure anchor="ospf_faemb_sub_tlv">
		<name>OSPF FAEMB Sub-TLV</name>
		<artwork name="" type="" align="left" alt=""><![CDATA[
	0 1 2 3	0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Type \| Length \|	\| Type \| Length \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Min Bandwidth \|	\| Min Bandwidth \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

	where:	]]></artwork>
		</figure>
	Type (2 octets):	<t>where:</t>
	A 16-bit field assigned by IANA (To Be Determined as TBD5).	<dl spacing="normal" newline="true">
	This value uniquely identifies the OSPF FAEMB sub-TLV.	<dt>Type (2 octets):</dt>
		<dd>A 16-bit field assigned by IANA (6). This value
	Length (2 octets):	uniquely identifies the OSPF FAEMB sub-TLV.</dd>
	A 16-bit field indicating the total length, in octets,	<dt>Length (2 octets):</dt>
	of the subsequent fields. For this sub-TLV, the Length is set to 4.	<dd>A 16-bit field indicating the total length, in octets, of the subsequent
		fields. For this sub-TLV, the Length is set to 4.</dd>
	Min Bandwidth (4 octets):	<dt>Min Bandwidth (4 octets):</dt>
	A 32-bit field specifying the link bandwidth encoded in	<dd>A 32-bit field specifying the link bandwidth encoded in IEEE floating
	IEEE floating point format (32 bits)[IEEE754-2019].	point format (32 bits)<xref target="IEEE754-2019"/>. The units are bytes per
	The units are bytes-per-second.	second.</dd>
		</dl>


	</artwork>	<t>The FAEMB sub-TLV <bcp14>MUST</bcp14> only appear once in the FAD s
	</figure>	ub-TLV.
	</t>	If it appears more than once, the OSPF FAD TLV <bcp14>MUST</bcp14> be
	<t>The FAEMB sub-TLV MUST only appear once in the FAD sub-TLV.
	If it appears more than once, the OSPF FAD TLV MUST be
	ignored by the receiver.</t>	ignored by the receiver.</t>

		<t>The Maximum Link Bandwidth as advertised in the Extended Link TLV
	<t>The Maximum Link Bandwidth as advertised in the Extended Link TLV	in the Extended Link Opaque LSA in OSPFv2 <xref target="RFC7684" format="defa
	in the Extended Link Opaque LSA in OSPFv2 <xref target ='RFC7684'/>	ult"/>
	or as a sub-TLV	or as a sub-TLV
	of the Router-Link TLV of the E-Router-LSA Router-Link TLV in	of the Router-Link TLV of the E-Router-LSA Router-Link TLV in

	OSPFv3 <xref target ='RFC8362'/> MUST be compared against	OSPFv3 <xref target="RFC8362" format="default"/> <bcp14>MUST</bcp14> be comp
	the Minimum bandwidth advertised in FAEMB sub-TLV.	ared against
	If the link bandwidth is lower than the Minimum bandwidth	the Minimum Bandwidth advertised in the FAEMB sub-TLV.
	advertised in FAEMB sub-TLV, the link MUST be excluded	If the link bandwidth value is lower than the Minimum Bandwidth
		advertised in the FAEMB sub-TLV, the link <bcp14>MUST</bcp14> be excluded
	from the Flex-Algorithm topology.	from the Flex-Algorithm topology.

	</t>	</t>
	<t>If a link does not have the Maximum Link Bandwidth advertised	<t>If a link does not have the Maximum Link Bandwidth advertised
	but the FAD contains this sub-TLV, then that link MUST be included in the	but the FAD contains the FAEMB sub-TLV, then that link <bcp14>MUST</bcp14> be
		included in the
	topology and proceed to apply further pruning rules for the link.	topology and proceed to apply further pruning rules for the link.

	</t>	</t>
	</section>	</section>
	<section title="OSPF Exclude Maximum Delay Sub-TLV"	<section anchor="sec_ospf_delay_exclusion" numbered="true" toc="default"
	anchor='sec_ospf_delay_exclusion'>	>
	<t>	<name>OSPF Exclude Maximum Delay Sub-TLV</name>
		<t>


	The OSPF Flex-Algorithm Exclude Maximum Delay sub-TLV (FAEMD) is a	The OSPF Flex-Algorithm Exclude Maximum Delay (FAEMD) sub-TLV is a
	sub-TLV of the OSPF FAD TLV. It has the following format.	sub-TLV of the OSPF FAD TLV. It has the following format.


	<figure anchor="ospf_faemd_sub_tlv" title="OSPF FAEMD Sub-TLV">	</t>
	<artwork>	<figure anchor="ospf_faemd_sub_tlv">
		<name>OSPF FAEMD Sub-TLV</name>
		<artwork name="" type="" align="left" alt=""><![CDATA[
	0 1 2 3	0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Type \| Length \|	\| Type \| Length \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

	\| RESERVED \| Max link Delay \|	\| RESERVED \| Max Link Delay \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

	where:	]]></artwork>
		</figure>
	Type (2 octets):
	A 16-bit field assigned by IANA (To Be Determined as TBD6).
	This value uniquely identifies the OSPF FAEMD sub-TLV.

	Length (2 octets):
	A 16-bit field indicating the total length, in octets,
	of the subsequent fields. For this sub-TLV, the Length is set to 4.

	Reserved (1 octet):
	Must set to zero by sender and
	must be ignored by receiver.


	Max link delay (3 octets):	<t>where:</t>
	A 24-bit field specifying the Maximum link delay in microseconds.	<dl spacing="normal" newline="true">
		<dt>Type (2 octets):</dt>
		<dd>A 16-bit field assigned by IANA (7). This value
		uniquely identifies the OSPF FAEMD sub-TLV.</dd>
		<dt>Length (2 octets):</dt>
		<dd>A 16-bit field indicating the total length, in octets, of the subsequent
		fields. For this sub-TLV, the Length is set to 4.</dd>
		<dt>Reserved (1 octet):</dt>
		<dd><bcp14>MUST</bcp14> be set to zero by the sender and <bcp14>MUST</bcp14> b
		e ignored by the receiver.</dd>
		<dt>Max Link Delay (3 octets):</dt>
		<dd>A 24-bit field specifying the Maximum link delay in microseconds.</dd>
		</dl>


	</artwork>	<t> The FAEMD sub-TLV <bcp14>MUST</bcp14> only appear once in the OSPF
	</figure>	FAD TLV.
	</t>	If it appears more than once, the OSPF FAD TLV <bcp14>MUST</bcp14> be
	<t> The FAEMD sub-TLV MUST only appear once in the OSPF FAD TLV.
	If it appears more than once, the OSPF FAD TLV MUST be
	ignored by the receiver.	ignored by the receiver.

	</t>	</t>
	<t>The Min Delay value advertised via the Min/Max Unidirectional Link Delay
	of ASLA sub-TLV <xref target ='RFC9492'/>, MUST be compared against the Maxi	<t>The Min Delay value advertised via the Min/Max Unidirectional Link
	mum delay	Delay
		of the ASLA sub-TLV <xref target="RFC9492" format="default"/> <bcp14>MUST</b
		cp14> be compared against the Maximum Delay
	advertised in the FAEMD sub-TLV. If the Min Unidirectional Link Delay is hig her	advertised in the FAEMD sub-TLV. If the Min Unidirectional Link Delay is hig her

	than the Maximum delay advertised in the FAEMD sub-TLV, the link MUST be	than the Maximum Delay advertised in the FAEMD sub-TLV, the link <bcp14>MUST </bcp14> be
	excluded from the Flex-Algorithm topology. If the	excluded from the Flex-Algorithm topology. If the
	Min/Max Unidirectional Link Delay is not advertised for a link but	Min/Max Unidirectional Link Delay is not advertised for a link but

	the FAD contains this sub-TLV,then then that link MUST NOT be	the FAD contains this sub-TLV, then that link <bcp14>MUST NOT</bcp14> be
	excluded from the topology based on the Maximum Delay constraint.	excluded from the topology based on the Maximum Delay constraint.

	</t>	</t>
	</section>	</section>
	</section>	</section>
	</section>	</section>
	<section title="Bandwidth Metric Advertisement"	<section anchor="sec_bw_metric" numbered="true" toc="default">
	anchor='sec_bw_metric'>	<name>Bandwidth Metric Advertisement</name>
		<t>
	<t>
	Historically, IGP implementations have made default metric	Historically, IGP implementations have made default metric

	assignments based on link bandwidth. This has proven to be useful,	assignments based on link bandwidth. This has proven to be useful
	but has suffered from having different defaults across	but has suffered from having different defaults across
	implementations and from the rapid growth of link bandwidths. With	implementations and from the rapid growth of link bandwidths. With
	Flex-Algorithm, the network administrator can define a function	Flex-Algorithm, the network administrator can define a function
	that will produce a metric for each link and have each node	that will produce a metric for each link and have each node
	automatically compute each link's metric based on its bandwidth.</t>	automatically compute each link's metric based on its bandwidth.</t>

		<t>This document defines a standard metric-type for this purpose
	<t>This document defines a standard metric type for this purpose	called the "Bandwidth Metric". The Bandwidth Metric <bcp14>MAY</bcp14> be
	called the "Bandwidth Metric". The Bandwidth Metric MAY be	advertised in the Generic Metric sub-TLV with the metric-type set
	advertised in the Generic Metric sub-TLV with the metric type set
	to "Bandwidth Metric". IS-IS and OSPF will advertise this type	to "Bandwidth Metric". IS-IS and OSPF will advertise this type

	of metric in their link advertisements. Bandwidth metric is a link	of metric in their link advertisements. The Bandwidth Metric is a link
	attribute and for the advertisement and processing of this attribute for	attribute, and it <bcp14>MUST</bcp14> follow <xref target="RFC9350" sectionFo
	Flex-algorithm, MUST follow the section 12 of	rmat="of" section="12"/> for its advertisement and processing during Flex-Algori
	<xref target ='RFC9350'/></t>	thm calculation.</t>
		<t> Flex-Algorithm uses this
	<t> Flex-Algorithm uses this	metric-type by specifying the bandwidth metric as the metric-type
	metric type by specifying the bandwidth metric as the metric type
	in a FAD TLV. A FAD TLV may also specify an automatic computation	in a FAD TLV. A FAD TLV may also specify an automatic computation
	of the bandwidth metric based on a link's advertised bandwidth. An	of the bandwidth metric based on a link's advertised bandwidth. An
	explicit advertisement of a link's bandwidth metric using the	explicit advertisement of a link's bandwidth metric using the
	Generic Metric sub-TLV overrides this automatic computation.	Generic Metric sub-TLV overrides this automatic computation.

	The automatic bandwidth metric calculation sub-TLVs are advertised	The automatic Bandwidth metric calculation sub-TLVs are advertised
	in the FAD TLV and these parameters are applicable to applications	in the FAD TLV, and these parameters are applicable to applications
	such as Flex-algorithm that make use of the FAD TLV.	such as Flex-Algorithm that make use of the FAD TLV.
	</t>	</t>

		<section anchor="sec_auto_metric" numbered="true" toc="default">
	<section title="Automatic Metric Calculation" anchor='sec_auto_metric'>	<name>Automatic Metric Calculation</name>
		<t> Networks that are designed to be highly regular and that follow unif
	<t> Networks which are designed to be highly regular and follow uniform	orm
	metric assignment may want to simplify their operations by	metric assignment may want to simplify their operations by
	automatically calculating the bandwidth metric. When	automatically calculating the bandwidth metric. When

	a FAD advertises the metric type as Bandwidth Metric and the link does	a FAD advertises the metric-type as Bandwidth Metric and the link does
	not have the Bandwidth Metric advertised, automatic metric derivation	not have the Bandwidth Metric advertised, automatic metric derivation
	can be used with additional FAD constraint advertisement as	can be used with additional FAD constraint advertisement as
	described in this section. </t>	described in this section. </t>

		<t> If a link's bandwidth changes, then the delay in learning about the
	<t> If a link's bandwidth changes, then the delay in learning about the
	change may create the possibility of micro-loops in the	change may create the possibility of micro-loops in the
	topology. This is no different from the IGP's susceptibility to	topology. This is no different from the IGP's susceptibility to
	micro-loops during a metric change. The micro-loop avoidance	micro-loops during a metric change. The micro-loop avoidance

	procedures described in <xref target ='I-D.bashandy-rtgwg-segment-routing-ulo	procedures described in <xref target="I-D.bashandy-rtgwg-segment-routing-uloo
	op'/>	p" format="default"/>
	or any other mechanism as described in the framework <xref target ='RFC5715'/	or any other mechanism as described in the framework <xref target="RFC5715" f
	>	ormat="default"/>
	can be used to avoid micro-loops when the automatic metric	can be used to avoid micro-loops when the automatic metric
	calculation is deployed.</t>	calculation is deployed.</t>

		<t> Computing the metric between adjacent systems based on bandwidth
	<t> Computing the metric between adjacent systems based on bandwidth
	becomes more complex in the case of parallel adjacencies. If there	becomes more complex in the case of parallel adjacencies. If there
	are parallel adjacencies between systems, then the bandwidth	are parallel adjacencies between systems, then the bandwidth
	between the systems is the sum of the bandwidth of the parallel	between the systems is the sum of the bandwidth of the parallel
	links. This is somewhat more complex to deal with, so there is an	links. This is somewhat more complex to deal with, so there is an
	optional mode for computing the aggregate bandwidth.</t>	optional mode for computing the aggregate bandwidth.</t>

		<section anchor="sec_auto_metric_mode" numbered="true" toc="default">
	<section title="Automatic Metric Calculation Modes"	<name>Automatic Metric Calculation Modes</name>
	anchor='sec_auto_metric_mode'>	<section anchor="sec_simple" numbered="true" toc="default">
		<name>Simple Mode</name>
	<section title="Simple Mode" anchor='sec_simple'>	<t> In Simple Mode, the Maximum Link Bandwidth of a single Layer 3 l
	<t> In simple mode, the Maximum Link Bandwidth of a single layer-3 link	ink
	is used to derive the metric. This mode is suitable for	is used to derive the metric. This mode is suitable for

	deployments that do not use parallel layer-3 links. In this case,	deployments that do not use parallel Layer 3 links. In this case,
	the computation of the metric is straightforward.	the computation of the metric is straightforward.


	If a layer-3 link is composed of a layer-2 bundle, then the link	If a Layer 3 link is composed of a Layer 2 bundle, then the link
	bandwidth is the sum of the bandwidths of the working components	bandwidth is the sum of the bandwidths of the working components

	and may vary with layer-2 link failures. </t>	and may vary with Layer 2 link failures. </t>
		</section>
	</section>	<section anchor="sec_intf_grp" numbered="true" toc="default">
		<name>Interface Group Mode</name>
	<section title="Interface Group Mode" anchor='sec_intf_grp'>	<t> The Simple Mode of metric calculation may not work well when the
	<t> The simple mode of metric calculation may not work well when there	re
	are multiple parallel layer-3 interfaces between two nodes.	are multiple parallel Layer 3 interfaces between two nodes.
	Ideally, the metric between two systems should be the same given	Ideally, the metric between two systems should be the same given
	the same bandwidth, whether the bandwidth is provided by parallel	the same bandwidth, whether the bandwidth is provided by parallel

	layer-2 links or parallel layer-3 links. To address this, in	Layer 2 links or parallel Layer 3 links. To address this, in
	Interface Group Mode, nodes MUST compute the aggregate bandwidth of	Interface Group Mode, nodes <bcp14>MUST</bcp14> compute the aggregate bandwid
	all parallel adjacencies, MUST derive the metric based on the	th of
	aggregate bandwidth, and MUST apply the resulting metric to each of	all parallel adjacencies, <bcp14>MUST</bcp14> derive the metric based on the
		aggregate bandwidth, and <bcp14>MUST</bcp14> apply the resulting metric to ea
		ch of
	the parallel adjacencies. Note that a single elephant flow is normally	the parallel adjacencies. Note that a single elephant flow is normally

	pinned to a single layer-3 interface. If the single layer-3 link	pinned to a single Layer 3 interface. If the single Layer 3 link
	bandwidth is not sufficient for any single elephant flow, the mechanisms	bandwidth is not sufficient for any single elephant flow, the mechanisms
	to solve this issue are outside the scope of this document.	to solve this issue are outside the scope of this document.

	<figure anchor="interface_grp" title="Parallel interfaces">	</t>
	<artwork>	<figure anchor="interface_grp">
		<name>Parallel Interfaces</name>
		<artwork name="" type="" align="left" alt=""><![CDATA[
	A------B====C====F====D	A------B====C====F====D
	\| \|	\| \|
	------E-------	------E-------

	</artwork>	]]></artwork>
	</figure>	</figure>
		<t>
	For example, in the above diagram, there are two parallel links	For example, in the above diagram, there are two parallel links

	between B->C, C->F, F->D. Let us assume the link bandwidth is	between B->C, C->F, F->D. Let us assume the link bandwidth is
	uniform 10Gbps on all links. When bandwidth is used to derive the metric	uniform 10 Gbps on all links. When bandwidth is used to derive the metric
	for the links, the metric for each link will be	for the links, the metric for each link will be

	the same. Traffic from B to D will be forwarded B->E->D as	the same. Traffic from B to D will be forwarded as B->E->D because
	the metric will be lower. Since the	the metric will be lower. Since the

	bandwidth is higher on the B->C->F->D path, the metric for that	bandwidth is higher on the B->C->F->D path, the metric for that
	path should be lower than the B->E->D path to attract the traffic on	path should be lower than the B->E->D path to attract the traffic on
	B->C->F->D path. Interface	the B->C->F->D path. Interface
	Group Mode should be preferred in cases where there are parallel layer-3	Group Mode should be preferred in cases where there are parallel Layer 3
	links.	links.

	</t>	</t>
	<t>	<t>
	In the interface group mode, every node MUST	In the Interface Group Mode, every node <bcp14>MUST</bcp14>
	identify the set of parallel links between a pair	identify the set of parallel links between a pair
	of nodes based on IGP link advertisements	of nodes based on IGP link advertisements

	and MUST consider cumulative bandwidth of the	and <bcp14>MUST</bcp14> consider cumulative bandwidth of the
	parallel links while arriving at the metric of each link. </t>	parallel links while arriving at the metric of each link. </t>

	<t>The parallel layer-3 links between two nodes may not have the	<t>The parallel Layer 3 links between two nodes may not have the
	same bandwidth. In such cases the method described in interface group	same bandwidth. In such cases, the method described in Interface Group
	mode will	Mode will
	result in same metric being used for all the parallel links which may	result in the same metric being used for all the parallel links, which
	cause	may cause
	undesired load-balancing on the links. In such cases, a device may loc	undesired load balancing on the links. In such cases, a device may loc
	ally	ally
	apply load-balancing factor relative to the link bandwidth on the ECMP	apply a load-balancing factor relative to the link bandwidth on the EC
	nexthops.	MP next hops.
	The load-balancing mechanisms are outside the scope of this document.< /t>	The load-balancing mechanisms are outside the scope of this document.< /t>

	</section>	</section>
	</section>	</section>
		<section anchor="sec_auto_metric_methods" numbered="true" toc="default">
	<section title="Automatic Metric Calculation Methods"	<name>Automatic Metric Calculation Methods</name>
	anchor='sec_auto_metric_methods'>	<t>
	<t>	In automatic metric calculation for simple and Interface Group Mode,
	In automatic metric calculation for simple and interface group mode,
	Maximum Link Bandwidth of the links is used to derive the metric.	Maximum Link Bandwidth of the links is used to derive the metric.
	There are two types of automatic metric derivation methods.</t>	There are two types of automatic metric derivation methods.</t>

	<t>	<ol type="1" spacing="normal">
	<list>	<li>Reference bandwidth method</li>
	<t> 1. Reference bandwidth method</t>	<li>Bandwidth thresholds method</li>
	<t> 2. Bandwidth thresholds method </t>	</ol>
	</list>
	</t>

	<section title="Reference Bandwidth method" anchor='sec_ref_bw_method'>


	<t>In many networks, the metric is inversely proportional to the link	<section anchor="sec_ref_bw_method" numbered="true" toc="default">
		<name>Reference Bandwidth Method</name>
		<t>In many networks, the metric is inversely proportional to the lin
		k
	bandwidth. The administrator or implementation selects a reference	bandwidth. The administrator or implementation selects a reference
	bandwidth and the metric is derived by dividing the reference	bandwidth and the metric is derived by dividing the reference
	bandwidth by the advertised Maximum Link Bandwidth. Advertising	bandwidth by the advertised Maximum Link Bandwidth. Advertising
	the reference bandwidth in the FAD constraints allows the metric	the reference bandwidth in the FAD constraints allows the metric
	computation to be done on every node for each link.	computation to be done on every node for each link.
	The metric is computed using reference bandwidth and the advertised link band width.	The metric is computed using reference bandwidth and the advertised link band width.
	Centralized control of this	Centralized control of this

	reference bandwidth simplifies management in the case that the	reference bandwidth simplifies management in the case where the
	reference bandwidth changes. In order to ensure that small	reference bandwidth changes. In order to ensure that small
	bandwidth changes do not change the link metric, it is useful to	bandwidth changes do not change the link metric, it is useful to
	define the granularity of the bandwidth that is of interest. The	define the granularity of the bandwidth that is of interest. The
	link bandwidth will be truncated to this granularity before	link bandwidth will be truncated to this granularity before
	deriving the metric. </t>	deriving the metric. </t>

		<t>For example,</t>
	<t>	<t indent="3">reference bandwidth = 1000G </t>
	For example,</t>	<t indent="3">Granularity = 20G </t>
	<t><list>	<t indent="3">The derived metric is 10 for link bandwidth in the
	<t>reference bandwidth = 1000G </t>	range 100G to 119G </t>
	<t>Granularity = 20G </t>	</section>
	<t>The derived metric is 10 for link bandwidth in the range 100G to 119G </t>	<section anchor="sec_bw_threshold_method" numbered="true" toc="default
	</list></t>	">
		<name>Bandwidth Thresholds Method</name>
	</section>	<t> The reference bandwidth approach described above provides a unif
		orm
	<section title="Bandwidth Thresholds method"	metric value for a range of link bandwidths. In certain cases,
	anchor='sec_bw_threshold_method'>
	<t> The reference bandwidth approach described above provides a uniform
	metric value for a range of link bandwidths. In certain cases
	there may be a need to define non-proportional metric values for	there may be a need to define non-proportional metric values for
	the varying ranges of link bandwidth. For example, bandwidths from	the varying ranges of link bandwidth. For example, bandwidths from
	10G to 30G are assigned metric value 100, bandwidth from 30G to 70G	10G to 30G are assigned metric value 100, bandwidth from 30G to 70G

	get a metric value of 50, and bandwidths greater than 70G have a	are assigned a metric value of 50, and bandwidths greater than 70G have a
	metric of 10. In order to support this, a staircase mapping based	metric of 10. In order to support this, a staircase mapping based
	on bandwidth thresholds is supported in the FAD. This	on bandwidth thresholds is supported in the FAD. This
	advertisement contains a set of threshold values and associated	advertisement contains a set of threshold values and associated
	metrics. </t>	metrics. </t>

	</section>	</section>
		</section>
	</section>	<section anchor="sec_auto_isis" numbered="true" toc="default">
		<name>IS-IS FAD Constraint Sub-TLVs for Automatic Metric Calculation</
	<section title="IS-IS FAD constraint Sub-TLVs for automatic metric calculation"	name>
	anchor='sec_auto_isis'>	<section anchor="sec_isis_auto_ref_bw" numbered="true" toc="default">
	<section title="Reference Bandwidth Sub-TLV" anchor='sec_isis_auto_ref_bw'>	<name>Reference Bandwidth Sub-TLV</name>
	<t>	<t>
	This section provides FAD constraint advertisement details for the	This section provides FAD constraint advertisement details for the

	reference bandwidth method of metric calculation as described in	reference bandwidth method of metric calculation, as described in
	<xref target ='sec_ref_bw_method'/>.	<xref target="sec_ref_bw_method" format="default"/>.


	The Flexible Algorithm Definition Reference Bandwidth sub-TLV (FADRB sub-TLV) is	The Flexible Algorithm Definition Reference Bandwidth (FADRB) sub-TLV is
	a sub-TLV of the IS-IS FAD sub-TLV. It has the following format:	a sub-TLV of the IS-IS FAD sub-TLV. It has the following format:


	<figure anchor="isis_fadrb_sub_tlv" title="IS-IS FADRB Sub-TLV">	</t>
	<artwork>	<figure anchor="isis_fadrb_sub_tlv">
		<name>IS-IS FADRB Sub-TLV</name>
		<artwork name="" type="" align="left" alt=""><![CDATA[
	0 1 2 3	0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Type \| Length \| Flags \|	\| Type \| Length \| Flags \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Reference Bandwidth \|	\| Reference Bandwidth \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Granularity Bandwidth \|	\| Granularity Bandwidth \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

		]]></artwork>
		</figure>


	where:	<t>where:</t>

	Type (1 octet):
	An 8-bit field assigned by IANA (To Be Determined as TBD7).
	This value uniquely identifies the IS-IS FADRB sub-TLV.

	Length (1 octet):
	An 8-bit field indicating the total length, in octets,
	of the subsequent fields. For this sub-TLV, the Length is set to 9.

	Flags (1 octet):
	An 8-bit field containing flags.


		<dl spacing="normal" newline="true">
		<dt>Type (1 octet):</dt>
		<dd>An 8-bit field assigned by IANA (8). This value
		uniquely identifies the IS-IS FADRB sub-TLV.</dd>
		<dt>Length (1 octet):</dt>
		<dd>An 8-bit field indicating the total length, in octets, of the subsequent
		fields. For this sub-TLV, the Length is set to 9.</dd>
		<dt>Flags (1 octet):</dt>
		<dd><t>An 8-bit field containing flags.</t>
		<artwork name="" type="" align="left" alt=""><![CDATA[
	0 1 2 3 4 5 6 7	0 1 2 3 4 5 6 7
	+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+
	\|G\| \|	\|G\| \|
	+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+

		]]></artwork></dd>


	G-flag: When set, Interface Group Mode MUST be used to	<dt>G-flag:</dt>
	derive total link bandwidth.	<dd>When set, Interface Group Mode <bcp14>MUST</bcp14> be used to derive
	Unassigned bits MUST be set to zero.	total link bandwidth. Unassigned bits <bcp14>MUST</bcp14> be set to
		zero and <bcp14>MUST</bcp14> be ignored by the receiver.</dd>
	Reference Bandwidth (4 octets):
	A 32-bit field with Bandwidth encoded in
	IEEE floating point format [IEEE754-2019].
	The units are bytes-per-second.

	Granularity Bandwidth (4 octets):
	A 32-bit field with Bandwidth encoded in
	IEEE floating point format [IEEE754-2019].
	The units are bytes-per-second.


	When granularity_bw is less than or equal to Total_link_bandwidth	<dt>Reference Bandwidth (4 octets):</dt>
		<dd>A 32-bit field with Bandwidth encoded in IEEE floating point format
		<xref target="IEEE754-2019"/>. The units are bytes per second.</dd>
		<dt>Granularity Bandwidth (4 octets):</dt>
		<dd>A 32-bit field with Bandwidth encoded in IEEE floating point format
		<xref target="IEEE754-2019"/>. The units are bytes per second.</dd>
		</dl>
		<t>When granularity_bw is less than or equal to Total_link_bandwidth, then:</t>


	Metric calculation: (Reference_bandwidth) /	<dl spacing="normal" newline="false">
	(Total_link_bandwidth -	<dt>Metric calculation:</dt><dd>(Reference_bandwidth) / (Total_link_bandwidth
	(Modulus of(Total_link_bandwidth,	- (Modulus of(Total_link_bandwidth, granularity_bw)))</dd>
	granularity_bw)))	</dl>


	When granularity_bw is greater than Total_link_bandwidth	<t>When granularity_bw is greater than Total_link_bandwidth, then:</t>
	Metric calculation: Reference_bandwidth /	<dl spacing="normal" newline="false">
	Total_link_bandwidth	<dt>Metric calculation:</dt><dd>Reference_bandwidth / Total_link_bandwidth</dd
		>
		</dl>


	The division used here is integer division.	<t>The division used here is integer division. Modulus of operation is
	Modulus of operation is defined as a remainder	defined as a remainder value when two numbers are divided.</t>
	value when two numbers are divided.


	</artwork>	<t> The Granularity Bandwidth value ensures that the metric
	</figure>
	</t>
	<t> The Granularity Bandwidth value ensures that the metric
	does not change when there is a small	does not change when there is a small
	change in the link bandwidth.	change in the link bandwidth.

	The IS-IS FADRB sub-TLV MUST NOT appear more than once in an IS-IS FAD	The IS-IS FADRB sub-TLV <bcp14>MUST NOT</bcp14> appear more than once in an I
	sub-TLV. If it appears more than once, the IS-IS FAD sub-TLV MUST be ignored	S-IS FAD
	by the receiver. The value advertised in the Reference Bandwidth field MUST b	sub-TLV. If it appears more than once, the IS-IS FAD sub-TLV <bcp14>MUST</bc
	e non-zero.	p14> be ignored
	If a zero value is advertised in the Reference Bandwidth Field in the IS-IS F	by the receiver. The value advertised in the Reference Bandwidth field <bcp14
	ADRB sub-TLV,	>MUST</bcp14> be non-zero.
	the sub-TLV MUST be ignored.</t>	If a zero value is advertised in the Reference Bandwidth field in the IS-IS F
	<t>If a Generic Metric sub-TLV with Bandwidth metric	ADRB sub-TLV,
	type is advertised for a link,	the sub-TLV <bcp14>MUST</bcp14> be ignored.</t>
	the Flex-Algorithm calculation MUST use the advertised Bandwidth Metric,	<t>If a Generic Metric sub-TLV with a Bandwidth metric-type
	and MUST NOT use the automatically derived metric for that link.	is advertised for a link,
	In case of Interface Group Mode, if all the parallel links have been	the Flex-Algorithm calculation <bcp14>MUST</bcp14> use the advertised Bandwid
	advertised with the Bandwidth Metric, The individual link Bandwidth Metric	th Metric
	MUST be used. If only some links among the parallel links have the Bandwidth	and <bcp14>MUST NOT</bcp14> use the automatically derived metric for that lin
	Metric advertisement, the Bandwidth Metric for such links MUST be ignored and	k.
	automatic Metric calculation MUST be used to derive link metric.	</t>
	</t>
	<t>If the calculated metric evaluates to zero, a metric of 1 MUST be used.</t
	>
	<t> If the calculated metric evaluates to a number greater than 0xFFFFFF,
	it is set to 0xFFFFFF.</t>
	</section>


	<section title="Bandwidth Thresholds Sub-TLV" anchor='sec_isis_threshold_metric' >
	<t>	<t>

		In case of Interface Group Mode, the following rules apply to parallel links:
		</t>

		<ul spacing="normal">
		<li>
		<t>If all the parallel links have been advertised with the Bandwidth Metric:
		</t>
		<t>The individual link Bandwidth Metric <bcp14>MUST</bcp14> be used.</t></li
		>

		<li>
		<t>If only some links among the parallel links have advertised the Bandwid
		th
		Metric:</t>

		<ul>
		<li>The Bandwidth Metric for such links <bcp14>MUST</bcp14> be ignored.</li>
		<li>Automatic metric calculation <bcp14>MUST</bcp14> be used to derive the l
		ink metric.</li>
		</ul>
		</li>
		</ul>

		<t>If the calculated metric evaluates to zero, a metric of 1 <bcp14>
		MUST</bcp14> be used.</t>
		<t> If the calculated metric evaluates to a number greater than 0xFF
		FFFF,
		it is set to 0xFFFFFF.</t>
		</section>
		<section anchor="sec_isis_threshold_metric" numbered="true" toc="defau
		lt">
		<name>Bandwidth Threshold Sub-TLV</name>
		<t>
	This section provides FAD constraint advertisement details for the	This section provides FAD constraint advertisement details for the
	Bandwidth Thresholds method of metric calculation as	Bandwidth Thresholds method of metric calculation as

	described in <xref target ='sec_bw_threshold_method'/>.	described in <xref target="sec_bw_threshold_method" format="default"/>.
	The Flexible Algorithm Definition Bandwidth Threshold sub-TLV (FADBT sub-TLV) is	The Flexible Algorithm Definition Bandwidth Threshold (FADBT) sub-TLV is
	a sub-TLV of the IS-IS FAD sub-TLV. It has the following format:	a sub-TLV of the IS-IS FAD sub-TLV. It has the following format:


	<figure anchor="isis_fadbt_sub_tlv" title="IS-IS FADBT Sub-TLV">	</t>
	<artwork>	<figure anchor="isis_fadbt_sub_tlv">
		<name>IS-IS FADBT Sub-TLV</name>
		<artwork name="" type="" align="left" alt=""><![CDATA[
	0 1 2 3	0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Type \| Length \| Flags \|	\| Type \| Length \| Flags \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Bandwidth Threshold 1 \|	\| Bandwidth Threshold 1 \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Threshold Metric 1 \|	\| Threshold Metric 1 \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Bandwidth Threshold 2 \|	\| Bandwidth Threshold 2 \|

	skipping to change at line 1035 ¶	skipping to change at line 937 ¶
	\| Bandwidth Threshold 3 \|	\| Bandwidth Threshold 3 \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	.....	.....
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Threshold Metric N-1 \|	\| Threshold Metric N-1 \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Bandwidth Threshold N \|	\| Bandwidth Threshold N \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Threshold Metric N \|	\| Threshold Metric N \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

		]]></artwork>
		</figure>


	where:	<t>where:</t>

	Type (1 octet):
	An 8-bit field assigned by IANA (To Be Determined as TBD8).
	This value uniquely identifies the IS-IS FADBT sub-TLV.

	Length (1 octet):
	An 8-bit field indicating the total length, in octets,
	of the subsequent fields. For this sub-TLV,
	the Length is calculated as (1+n*7). Here n is equal
	to number of Threshold Metrics specified.
	n MUST be greater than or equal to 1

	Flags (1 octet):


		<dl spacing="normal" newline="true">
		<dt>Type (1 octet):</dt>
		<dd> An 8-bit field assigned by IANA (9). This value
		uniquely identifies the IS-IS FADBT sub-TLV.</dd>
		<dt>Length (1 octet):</dt>
		<dd>An 8-bit field indicating the total length, in octets, of the subsequent
		fields. For this sub-TLV, the Length is calculated as (1+N*7). Here, N is
		equal to the number of Threshold Metrics specified. N <bcp14>MUST</bcp14> be
		greater than or equal to 1.</dd>
		<dt>Flags (1 octet):</dt>
		<dd><artwork name="" type="" align="left" alt=""><![CDATA[
	0 1 2 3 4 5 6 7	0 1 2 3 4 5 6 7
	+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+
	\|G\| \| \| \|	\|G\| \| \| \|
	+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+

		]]></artwork>
		<dl spacing="normal" newline="false">
		<dt>G-flag:</dt><dd>When set, Interface Group Mode <bcp14>MUST</bcp14> be
		used to derive total link bandwidth. Unassigned bits <bcp14>MUST</bcp14> be se
		t to zero and <bcp14>MUST</bcp14> be ignored by the receiver.</dd>
		</dl>
		</dd>
		</dl>


	G-flag: when set, interface group Mode MUST be used to derive	<t>Following is the staircase bandwidth threshold and associated metric values.<
	total link bandwidth.	/t>
	Unassigned bits MUST be set to zero.

	Staircase bandwidth threshold and associated metric values.

	Bandwidth Threshold 1 (4 octets):
	Minimum Link Bandwidth is encoded in in
	IEEE floating point format (32 bits)[IEEE754-2019].
	The units are bytes-per-second.

	Threshold Metric 1 (3 octets):
	Metric value range (1 - 16,777,215 (0xFFFFFF))

	Bandwidth Threshold n (4 octets):
	Maximum Link Bandwidth is encoded in
	IEEE floating point format (32 bits)[IEEE754-2019].
	The units are bytes-per-second.

	Threshold Metric n (3 octest) :
	Metric value range (1 - 16,777,215 (0xFFFFFF))

	</artwork>
	</figure>
	</t>


	<t>When G-flag is set, the cumulative bandwidth of the	<dl spacing="normal" newline="true">
	parallel links is computed	<dt>Bandwidth Threshold 1 (4 octets):</dt>
	as described in <xref target ='sec_intf_grp'/>. If G-flag is	<dd>Minimum Link Bandwidth is encoded in IEEE floating point format (32
	not set, the advertised Maximum Link	bits)<xref target="IEEE754-2019"/>. The units are bytes per second.</dd>
	Bandwidth is used.</t>	<dt>Threshold Metric 1 (3 octets):</dt>
	<t>Assignment of Bandwidth Metric Based on Computed Link Bandwidth:</t>	<dd>Metric value range (1 - 16,777,215 (0xFFFFFF))</dd>
		<dt>Bandwidth Threshold N (4 octets):</dt>
		<dd>Maximum Link Bandwidth is encoded in IEEE floating point format (32
		bits)<xref target="IEEE754-2019"/>. The units are bytes per second.</dd>
		<dt>Threshold Metric N (3 octets):</dt>
		<dd>Metric value range (1 - 16,777,215 (0xFFFFFF))</dd>
		</dl>


	<t>The Bandwidth Metric for a link during the Flex-Algorithm Shortest	<t>When the G-flag is set, the cumulative bandwidth of the parallel links is
	Path First (SPF) calculation MUST be assigned according to	computed as described in <xref target="sec_intf_grp" format="default"/>. If the
	the following rules:</t>	G-flag is not set, the advertised Maximum Link Bandwidth is used.</t>
	<t>
	<list>
	<t>1. When the computed link bandwidth is less than Bandwidth Threshold 1
	:
	<ul>
	<li> The Bandwidth Metric MUST be set to the maximum metric value of 4,26
	1,412,864.</li>
	</ul>
	</t>
	<t>2. When the computed link bandwidth is greater than or equal to
	Bandwidth Threshold 1 and less than Bandwidth Threshold 2:
	<ul>
	<li> The Bandwidth Metric MUST be set to Threshold Metric 1.</li>
	</ul>
	</t>


	<t>3. When the computed link bandwidth is greater than or equal	<t>The assignment of the Bandwidth Metric based on computed link bandwidth is de
	to Bandwidth Threshold 2 and less than Bandwidth Threshold 3:	scribed below.</t>
	<ul>	<t>The Bandwidth Metric for a link during the Flex-Algorithm Shortest Path
	<li> The Bandwidth Metric MUST be set to Threshold Metric 2.</li>	First (SPF) calculation <bcp14>MUST</bcp14> be assigned according to the
	</ul>	following rules:</t>
	</t>	<ol type="1" spacing="normal">
		<li><t>When the computed link bandwidth is less than Bandwidth Threshold 1:
		</t>
		<t>The Bandwidth Metric <bcp14>MUST</bcp14> be set to the maximum metric va
		lue of 4,261,412,864.</t>
		</li>
		<li><t>When the computed link bandwidth is greater than or equal to
		Bandwidth Threshold 1 and less than Bandwidth Threshold 2:</t>
		<t>The Bandwidth Metric <bcp14>MUST</bcp14> be set to Threshold Metric 1.</
		t>
		</li>
		<li><t>When the computed link bandwidth is greater than or equal to
		Bandwidth Threshold 2 and less than Bandwidth Threshold 3:</t>
		<t>The Bandwidth Metric <bcp14>MUST</bcp14> be set to Threshold Metric 2.</
		t>
		</li>
		<li><t>In general, for all integer values of X such that 1 ≤ X < N:</t>
		<t>When the computed link bandwidth is greater than or equal to Bandwidth
		Threshold X and less than Bandwidth Threshold X+1:</t>
		<t>The Bandwidth Metric <bcp14>MUST</bcp14> be set to Threshold Metric X.</
		t>
		</li>
		<li><t>When the computed link bandwidth is greater than or equal to Bandwid
		th Threshold N:</t>
		<t>The Bandwidth Metric <bcp14>MUST</bcp14> be set to Threshold Metric N.</
		t>
		</li>
		</ol>


	<t>4. In general, for all integer values of X such that 1 ≤ X < N:	<t>Notes:</t>
	<ul>	<ul spacing="normal">
	<li> When the computed link bandwidth is greater than or equal to	<li>The term "Bandwidth Threshold X" refers to a predefined threshold
	Bandwidth Threshold X and less than Bandwidth Threshold X+1:</li>	value corresponding to the index X.</li>
	<li> The Bandwidth Metric MUST be set to Threshold Metric X.</li>	<li>The term "Threshold Metric X" refers to the metric value
	</ul>	associated with Bandwidth Threshold X.</li>
	</t>	<li>N represents the total number of bandwidth thresholds
		defined in the system.</li>
		</ul>


	<t>5. When the computed link bandwidth is greater than or equal to Bandwidth	<t>Implementations <bcp14>MUST</bcp14> ensure that these rules are c
	Threshold N:	onsistently applied to
	<ul>
	<li> The Bandwidth Metric MUST be set to Threshold Metric N.</l
	i>
	</ul>
	</t>
	</list>
	</t>
	<t>Notes:
	<list>
	<t>The term Bandwidth Threshold X refers to a predefined threshold
	value corresponding to the index X.</t>
	<t>The term Threshold Metric X refers to the metric value
	associated with Bandwidth Threshold X.</t>
	<t>N represents the total number of bandwidth thresholds
	defined in the system.</t>
	</list>
	</t>
	<t>Implementations MUST ensure that these rules are consistently applied to
	maintain interoperability and optimal path computation	maintain interoperability and optimal path computation
	within the network.</t>	within the network.</t>

		<t>The IS-IS FADBT sub-TLV <bcp14>MUST NOT</bcp14> appear more than
	<t>The IS-IS FADBT sub-TLV MUST NOT appear more than once in an IS-IS FAD	once in an IS-IS FAD
	sub-TLV. If it appears more than once, the IS-IS FAD sub-TLV MUST	sub-TLV. If it appears more than once, the IS-IS FAD sub-TLV <bcp14>MUST</bc
		p14>
	be ignored by the receiver.</t>	be ignored by the receiver.</t>

		<t>A FAD <bcp14>MUST NOT</bcp14> contain both the FADBT sub-TLV and
		the FADRB sub-TLV. If both
		of these sub-TLVs are advertised in the same FAD for a Flexible
		Algorithm, the FAD <bcp14>MUST</bcp14> be ignored by the receiver.</t>
		<t>If a Generic Metric sub-TLV with Bandwidth metric-type is adverti
		sed
		for a link, the Flex-Algorithm calculation <bcp14>MUST</bcp14> use the Bandwi
		dth
		Metric advertised on the link and <bcp14>MUST NOT</bcp14> use the automatical
		ly
		derived metric for that link.</t>


	<t>A FAD MUST NOT contain both the FADBT sub-TLV and the FADRB sub-TLV. If b	<t>In case of Interface Group Mode, the following rules apply to parallel links:
	oth	</t>
	these sub-TLVs are advertised in the same FAD for a Flexible	<ul spacing="normal">
	Algorithm, the FAD MUST be ignored by the receiver.</t>	<li>
		<t>If all the parallel links have been advertised with the Bandwidth Metric:
	<t>If a Generic Metric sub-TLV with Bandwidth metric type is advertised	</t>
	for a link, the Flex-Algorithm calculation MUST use the Bandwidth	<t>The individual link Bandwidth Metric <bcp14>MUST</bcp14> be used.</t></li>
	Metric advertised on the link, and MUST NOT use the automatically	<li>
	derived metric for that link.</t>	<t>If only some links among the parallel links have advertised the Bandwidth
		Metric:</t>
	<t>In case of Interface Group Mode, if all the parallel links	<ul>
	have been advertised with the Bandwidth Metric, The individual
	link Bandwidth Metric MUST be used. If only some links among
	the parallel links have the Bandwidth Metric advertisement,
	the Bandwidth Metric for such links MUST be ignored and
	automatic Metric calculation MUST be used to derive link metric.</t>

	</section>
	</section>


	<section title="OSPF FAD constraint Sub-TLVs for automatic metric calculation"	<li>The Bandwidth Metric for such links <bcp14>MUST</bcp14> be ignored.</li>
	anchor='sec_auto_ospf'>	<li>Automatic metric calculation <bcp14>MUST</bcp14> be used to derive the l
	<section title="Reference Bandwidth Sub-TLV" anchor='sec_ospf_auto_ref_bw'>	ink metric.</li></ul>
	<t>	</li>
	The Flexible Algorithm Definition Reference Bandwidth sub-TLV (FADRB sub-TLV) is	</ul>
		</section>
		</section>
		<section anchor="sec_auto_ospf" numbered="true" toc="default">
		<name>OSPF FAD Constraint Sub-TLVs for Automatic Metric Calculation</n
		ame>
		<section anchor="sec_ospf_auto_ref_bw" numbered="true" toc="default">
		<name>Reference Bandwidth Sub-TLV</name>
		<t>
		The Flexible Algorithm Definition Reference Bandwidth (FADRB) sub-TLV is
	a sub-TLV of the OSPF FAD TLV. It has the following format:	a sub-TLV of the OSPF FAD TLV. It has the following format:


	<figure anchor="ospf_fadrb_sub_tlv" title="OSPF FADRB Sub-TLV">	</t>
	<artwork>	<figure anchor="ospf_fadrb_sub_tlv">
		<name>OSPF FADRB Sub-TLV</name>
		<artwork name="" type="" align="left" alt=""><![CDATA[
	0 1 2 3	0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Type \| Length \|	\| Type \| Length \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Flags \| Reserved \|	\| Flags \| Reserved \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Reference Bandwidth \|	\| Reference Bandwidth \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Granularity Bandwidth \|	\| Granularity Bandwidth \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

		]]></artwork>
		</figure>


	where:	<t>where:</t>

	Type (2 octets):
	A 16-bit field assigned by IANA (To Be Determined as TBD9).
	This value uniquely identifies the OSPF FADRB sub-TLV.

	Length (2 octets):
	A 16-bit field indicating the total length, in octets,
	of the subsequent fields. For this sub-TLV, Length is set to 14.

	Flags (1 octet):


		<dl spacing="normal" newline="true">
		<dt>Type (2 octets):</dt>
		<dd>A 16-bit field assigned by IANA (8). This value
		uniquely identifies the OSPF FADRB sub-TLV.</dd>
		<dt>Length (2 octets):</dt>
		<dd>A 16-bit field indicating the total length, in octets, of the subsequent
		fields. For this sub-TLV, Length is set to 14.</dd>
		<dt>Flags (1 octet):</dt>
		<dd><artwork name="" type="" align="left" alt=""><![CDATA[
	0 1 2 3 4 5 6 7	0 1 2 3 4 5 6 7
	+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+
	\|G\| \| \| \|	\|G\| \| \| \|
	+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+

		]]></artwork>
		<dl spacing="normal" newline="false">
		<dt>G-flag:</dt><dd>When set, Interface Group Mode <bcp14>MUST</bcp14> be
		used to derive total link bandwidth. Unassigned bits <bcp14>MUST</bcp14> be
		set to zero and <bcp14>MUST</bcp14> be ignored by the receiver.</dd>
		</dl></dd>
		<dt>Reference Bandwidth (4 octets):</dt>
		<dd>Bandwidth encoded in 32 bits in IEEE floating point format
		<xref target="IEEE754-2019"/>. The units are in bytes per second.</dd>
		<dt>Granularity Bandwidth (4 octets):</dt>
		<dd>Bandwidth encoded in 32 bits in IEEE floating point format
		<xref target="IEEE754-2019"/>. The units are in bytes per second.</dd>
		</dl>


	G-flag: When set, Interface Group Mode MUST be used	<t>When granularity_bw is less than or equal to Total_link_bandwidth, then:</t>
	to derive total link bandwidth.
	Unassigned bits MUST be set to zero.

	Reference Bandwidth (4 octets):
	Bandwidth encoded in 32 bits in
	IEEE floating point format [IEEE754-2019].
	The units are in bytes per second.
	Granularity Bandwidth (4 octets):
	Bandwidth encoded in 32 bits in
	IEEE floating point format [IEEE754-2019].
	The units are in bytes per second.

	When granularity_bw is less than or equal to Total_link_bandwidth


	Metric calculation: (Reference_bandwidth) /	<dl spacing="normal" newline="true">
	(Total_link_bandwidth -	<dt>Metric calculation:</dt><dd>(Reference_bandwidth) /
	(Modulus of(Total_link_bandwidth,	(Total_link_bandwidth - (Modulus of(Total_link_bandwidth,
	granularity_bw)))	granularity_bw)))</dd>
		</dl>


	When granularity_bw is greater than Total_link_bandwidth	<t>When granularity_bw is greater than Total_link_bandwidth, then:</t>


	Metric calculation: Reference_bandwidth/	<dl spacing="normal" newline="true">
	Total_link_bandwidth	<dt>Metric calculation:</dt><dd>Reference_bandwidth/
		Total_link_bandwidth</dd>
		</dl>


	The division used here is integer division.	<t>The division used here is integer division.</t>


	Modulus of operation is defined as a remainder	<t>Modulus of operation is defined as a remainder value when two numbers are
	value when two numbers are divided.	divided.</t>
	</artwork>
	</figure>


	The Granularity Bandwidth value is used to ensure that the	<t>The Granularity Bandwidth value is used to ensure that the metric does not
	metric does not change when there is a small	change when there is a small change in the link bandwidth. The OSPF FADRB
	change in the link bandwidth.	sub-TLV <bcp14>MUST NOT</bcp14> appear more than once in an OSPF FAD TLV. If
	The OSPF FADRB sub-TLV MUST NOT appear more than once in an OSPF FAD	it appears more than once, the OSPF FAD TLV <bcp14>MUST</bcp14> be ignored by
	TLV. If it appears more than once, the OSPF FAD TLV MUST be ignored	the receiver. The value advertised in the Reference Bandwidth field
	by the receiver.The value advertised in the Reference Bandwidth field MUST be	<bcp14>MUST</bcp14> be non-zero. If a zero value is advertised in the
	non-zero.	Reference Bandwidth field in the OSPF FADRB sub-TLV, the sub-TLV
	If a zero value is advertised in the Reference Bandwidth Field in the OSPF FA	<bcp14>MUST</bcp14> be ignored. If a Generic Metric sub-TLV with Bandwidth
	DRB sub-TLV,	metric-type is advertised for a link, the Flex-Algorithm calculation
	the sub-TLV MUST be ignored.	<bcp14>MUST</bcp14> use the advertised Bandwidth Metric on the link and
	If a Generic Metric sub-TLV with Bandwidth metric type is	<bcp14>MUST NOT</bcp14> use the automatically derived metric for that link.
	advertised for a link, the Flex-Algorithm calculation MUST use	In the case of Interface Group Mode, the following procedures apply:
	the advertised Bandwidth Metric	</t>
	on the link, and MUST NOT use the automatically derived	<ul spacing="normal">
	metric for that link.	<li>
	In the case of Interface Group Mode, the following procedures apply:	<t> When all parallel links have advertised the Bandwidth
	<list>	Metric: The individual link Bandwidth Metric
	<t> When all parallel links have advertised the Bandwidth Metric:	<bcp14>MUST</bcp14> be used for each link.</t>
	The individual link Bandwidth Metric MUST be used for each link.</t>	</li>
	<t> When only a subset of the parallel links have advertised	<li>
	the Bandwidth Metric: The Bandwidth Metric advertisements for	<t> When only a subset of the parallel links have advertised
	those links MUST be ignored. In this scenario, automatic	the Bandwidth Metric: The Bandwidth Metric advertisements for
	metric calculation MUST be used to derive the link metrics	those links <bcp14>MUST</bcp14> be ignored. In this scenario,
	for all parallel links.</t>	automatic metric calculation <bcp14>MUST</bcp14> be used to
	</list>	derive the link metrics for all parallel links.</t>
		</li>
		</ul>


	</t>	<t>If the calculated metric evaluates to zero, a metric of 1 <bcp14>
	<t>If the calculated metric evaluates to zero, a metric of 1 MUST be used.</t>	MUST</bcp14> be used.</t>
	<t> If the calculated metric evaluates to a number greater than 0xFFFFFFFF,	<t> If the calculated metric evaluates to a number greater than 0xFF
		FFFFFF,
	it is set to 0xFFFFFFFF.</t>	it is set to 0xFFFFFFFF.</t>

	</section>	</section>
		<section anchor="sec_ospf_threshold_metric" numbered="true" toc="defau
	<section title="Bandwidth Threshold Sub-TLV" anchor='sec_ospf_threshold_metric'>	lt">
	<t>	<name>Bandwidth Threshold Sub-TLV</name>
	The Flexible Algorithm Definition Bandwidth Thresholds sub-TLV	<t>
	(FADBT sub-TLV) is	The Flexible Algorithm Definition Bandwidth Threshold (FADBT) sub-TLV is
	a sub-TLV of the OSPF FAD TLV. It has the following format:	a sub-TLV of the OSPF FAD TLV. It has the following format:


	<figure anchor="ospf_fadbt_sub_tlv" title="OSPF FADBT Sub-TLV">	</t>
	<artwork>	<figure anchor="ospf_fadbt_sub_tlv">
		<name>OSPF FADBT Sub-TLV</name>
		<artwork name="" type="" align="left" alt=""><![CDATA[
	0 1 2 3	0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Type \| Length \|	\| Type \| Length \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Flags \| Reserved \|	\| Flags \| Reserved \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Bandwidth Threshold 1 \|	\| Bandwidth Threshold 1 \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Threshold Metric 1 \|	\| Threshold Metric 1 \|

	skipping to change at line 1300 ¶	skipping to change at line 1190 ¶
	\| Bandwidth Threshold 3 \|	\| Bandwidth Threshold 3 \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	.....	.....
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Threshold Metric N-1 \|	\| Threshold Metric N-1 \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Bandwidth Threshold N \|	\| Bandwidth Threshold N \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	\| Threshold Metric N \|	\| Threshold Metric N \|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

		]]></artwork>
		</figure>


	where:	<t>where:</t>
	Type (2 octets):	<dl spacing="normal" newline="true">
	A 16-bit field assigned by IANA (To Be Determined as TBD10).	<dt>Type (2 octets):</dt>
	This value uniquely identifies the OSPF FADBT sub-TLV.	<dd>A 16-bit field assigned by IANA (9). This value
		uniquely identifies the OSPF FADBT sub-TLV.</dd>
	Length (2 octets):	<dt>Length (2 octets):</dt>
	A 16-bit field indicating the total length, in octets,	<dd>A 16-bit field indicating the total length, in octets, of the subsequent
	of the subsequent fields. For this sub-TLV, Length is set	fields. For this sub-TLV, Length is set to 2 + N*8 octets. Here, N is equal to
	2 + N*8 octets. Here N is equal to number of	the number of Threshold Metrics specified. N <bcp14>MUST</bcp14> be greater th
	Threshold Metrics specified. N MUST be greater than or equal to 1.	an
		or equal to 1.</dd>
	Flags (1 octet):	<dt>Flags (1 octet):</dt>
		<dd>
		<artwork name="" type="" align="left" alt=""><![CDATA[
	0 1 2 3 4 5 6 7	0 1 2 3 4 5 6 7
	+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+
	\|G\| \|	\|G\| \|
	+-+-+-+-+-+-+-+-+	+-+-+-+-+-+-+-+-+

		]]></artwork>
		<dl spacing="normal" newline="false">
		<dt>G-flag:</dt><dd>When set, Interface Group Mode <bcp14>MUST</bcp14>
		be used to derive total link bandwidth. Unassigned bits <bcp14>MUST</bcp14
		> be set to zero and <bcp14>MUST</bcp14> be ignored by the receiver.</dd>
		</dl>
		</dd>
		</dl>


	G-flag: when set, interface group Mode MUST be used to	<t>Following is the staircase bandwidth threshold and associated metric values.<
	derive total link bandwidth.	/t>
	Unassigned bits MUST be set to zero.

	Staircase bandwidth threshold and associated metric values.

	Bandwidth Threshold 1 (4 octets):
	Minimum Link Bandwidth is encoded
	in IEEE floating point format (32 bits)[IEEE754-2019].
	The units are bytes per second.

	Threshold Metric 1 (4 octets):
	Metric value range (1 - 4,294,967,296 (0xFFFFFFFF))

	Bandwidth Threshold N (4 octets):
	Maximum Link Bandwidth is encoded
	in IEEE floating point format (32 bits)[IEEE754-2019].
	The units are bytes per second.


	Threshold Metric N (4 octets):	<dl spacing="normal" newline="true">
	Metric value range (1 - 4,294,967,296 (0xFFFFFFFF))	<dt>Bandwidth Threshold 1 (4 octets):</dt>
		<dd>Minimum Link Bandwidth is encoded in IEEE floating point format (32
		bits)<xref target="IEEE754-2019"/>. The units are bytes per second.</dd>
		<dt>Threshold Metric 1 (4 octets):</dt>
		<dd>Metric value range (1 - 4,294,967,296 (0xFFFFFFFF))</dd>
		<dt>Bandwidth Threshold N (4 octets): </dt>
		<dd>Maximum Link Bandwidth is encoded in IEEE floating point format (32
		bits)<xref target="IEEE754-2019"/>. The units are bytes per second.</dd>
		<dt>Threshold Metric N (4 octets):</dt>
		<dd>Metric value range (1 - 4,294,967,296 (0xFFFFFFFF))</dd>
		</dl>


	</artwork>	<t>When the G-flag is set, the cumulative bandwidth of the parallel links is
	</figure>	computed as described in <xref target="sec_intf_grp" format="default"/>. If
	</t>	the G-flag is not set, the advertised Maximum Link Bandwidth is used.</t>


	<t>When G-flag is set, the cumulative bandwidth of the parallel links is	<t>The assignment of the Bandwidth Metric based on computed link bandwidth is de
	computed as described in <xref target ='sec_intf_grp'/>.	scribed below.</t>
	If G-flag is not set, the advertised Maximum Link	<t>During the Flex-Algorithm SPF calculation, the Bandwidth Metric for a link <
	Bandwidth is used.</t>	bcp14>MUST</bcp14> be assigned according to the following rules:</t>


	<t>Assignment of Bandwidth Metric Based on Computed Link Bandwidth:</t>	<ol type="1" spacing="normal">
		<li><t>When the computed link bandwidth is less than Bandwidth Threshold 1:</t
		>
		<t>The Bandwidth Metric <bcp14>MUST</bcp14> be set to the maximum metric
		value of 4,294,967,296.</t></li>
		<li><t>When the computed link bandwidth is greater than or equal to
		Bandwidth Threshold 1 and less than Bandwidth Threshold 2:</t>
		<t>The Bandwidth Metric <bcp14>MUST</bcp14> be set to Threshold Metric 1.</t>
		</li>
		<li><t>When the computed link bandwidth is greater than or equal to
		Bandwidth Threshold 2 and less than Bandwidth Threshold 3:</t>
		<t>The Bandwidth Metric <bcp14>MUST</bcp14> be set to Threshold Metric 2.</t><
		/li>
		<li><t>In general, for all integer values of X where 1 ≤X < N:</t>
		<t>When the computed link bandwidth is greater than or equal to Bandwidth
		Threshold X and less than Bandwidth Threshold X+1:</t>
		<t>The Bandwidth Metric <bcp14>MUST</bcp14> be set to Threshold Metric X.</t><
		/li>
		<li><t>When the computed link bandwidth is greater than or equal to
		Bandwidth Threshold N:</t>
		<t>The Bandwidth Metric <bcp14>MUST</bcp14> be set to Threshold Metric N.</t><
		/li>
		</ol>


	<t>The Bandwidth Metric for a link during the Flex-Algorithm	<t>Notes:</t>
	Shortest Path First (SPF) calculation MUST be assigned according	<ul spacing="normal">
	to the following rules:</t>	<li>
	<t>	<t>Bandwidth Threshold X refers to the predefined bandwidth threshold
	<list>	corresponding to index X.</t>
	<t>1. When the computed link bandwidth is less than Bandwidth Threshold 1:	</li>
	<ul>	<li>
	<li>The Bandwidth Metric MUST be set to the maximum metric	<t>Threshold Metric X is the metric value associated with Bandwidth
	value of 4,294,967,296.</li>	Threshold X.</t>
	</ul>	</li>
	</t>	<li>
	<t>2. When the computed link bandwidth is greater than or equal	<t>N represents the total number of bandwidth thresholds defined in the
	to Bandwidth Threshold 1 and less than Bandwidth Threshold 2:	system.</t>
	<ul>	</li>
	<li>The Bandwidth Metric MUST be set to Threshold Metric 1.</li>	</ul>
	</ul>
	</t>
	<t>3. When the computed link bandwidth is greater than or equal
	to Bandwidth Threshold 2 and less than Bandwidth Threshold 3:
	<ul>
	<li> The Bandwidth Metric MUST be set to Threshold Metric 2.</li>
	</ul>
	</t>
	<t>4. In general, for all integer values of X where 1 ≤X < N:
	<ul>
	<li>When the computed link bandwidth is greater than or equal to
	Bandwidth Threshold X and less than Bandwidth Threshold X+1:</li>
	<li>The Bandwidth Metric MUST be set to Threshold Metric X.</li>
	</ul>
	</t>
	<t>5. When the computed link bandwidth is greater than or equal
	to Bandwidth Threshold N:
	<ul>
	<li>The Bandwidth Metric MUST be set to Threshold Metric N.</li>
	</ul>
	</t>
	</list>
	</t>
	<t>Notes:
	<list>
	<t>Bandwidth Threshold X refers to the predefined bandwidth
	threshold corresponding to index X.</t>
	<t>Threshold Metric X is the metric value associated with
	Bandwidth Threshold X.</t>
	<t>N represents the total number of bandwidth thresholds
	defined in the system.</t>


	</list>	<t>Implementations <bcp14>MUST</bcp14> consistently apply these rule
	</t>	s to ensure accurate
	<t>Implementations MUST consistently apply these rules to ensure accurate
	path computations and maintain interoperability within the network.</t>	path computations and maintain interoperability within the network.</t>

		<t>The OSPF FADBT sub-TLV <bcp14>MUST NOT</bcp14> appear more than o
	<t>The OSPF FADBT sub-TLV MUST NOT appear more than once in an OSPF FAD	nce in an OSPF FAD
	sub-TLV. If it appears more than once, the OSPF FAD MUST	sub-TLV. If it appears more than once, the OSPF FAD sub-TLV <bcp14>MUST</bcp
		14>
	be ignored by the receiver.</t>	be ignored by the receiver.</t>

		<t>A FAD <bcp14>MUST NOT</bcp14> contain both the FADBT sub-TLV and
	<t>A FAD MUST NOT contain both the FADBT sub-TLV and the FADRB sub-TLV. If b	the FADRB sub-TLV. If both
	oth
	these sub-TLVs are advertised in the same FAD for a Flexible	these sub-TLVs are advertised in the same FAD for a Flexible

	Algorithm, the FAD MUST be ignored by the receiver.</t>	Algorithm, the FAD <bcp14>MUST</bcp14> be ignored by the receiver.</t>
		<t>If a Generic Metric sub-TLV with Bandwidth metric-type is adverti
	<t>If a Generic Metric sub-TLV with Bandwidth metric type is advertised	sed
	for a link, the Flex-Algorithm calculation MUST use the Bandwidth	for a link, the Flex-Algorithm calculation <bcp14>MUST</bcp14> use the Bandwi
	Metric advertised on the link, and MUST NOT use the automatically	dth
		Metric advertised on the link and <bcp14>MUST NOT</bcp14> use the automatical
		ly
	derived metric for that link.</t>	derived metric for that link.</t>

		<t> Metric Assignment in Interface Group Mode:</t>
		<t>When a link does not have a configured Bandwidth Metric,
		the automatically derived metric <bcp14>MUST</bcp14> be used for that link.</
		t>
		<t>In case of Interface Group Mode, the following rules apply to par
		allel links:</t>
		<ul spacing="normal">
		<li>
		<t>If all parallel links have advertised the Bandwidth Metric:</
		t>
		<t>The individual link Bandwidth Metric <bcp14>MUST</bcp14> be u
		sed for each link during path computation.</t></li>


	<t> Metric Assignment in Interface Group Mode:</t>	<li>
	<t>When a link does not have a configured Bandwidth Metric,	<t>If only some of the parallel links have advertised the Bandwi
	the automatically derived metric MUST be used for that link.</t>	dth Metric:</t>
		<ul>
		<li>The Bandwidth Metric advertisements for those links <bcp14
		>MUST</bcp14> be ignored.</li>
		<li>Automatic metric calculation <bcp14>MUST</bcp14> be used t
		o derive the link metrics for all parallel links.</li>
		</ul>
		</li>
		</ul>


	<t>In the context of Interface Group Mode, the following rules apply to parallel	<t>This approach ensures consistent metric calculation and avoids di
	links:</t>	screpancies
	<t>
	<list>
	<t> If all parallel links have advertised the Bandwidth Metric:
	<ul>
	<li>The individual link Bandwidth Metrics MUST be used for each link duri
	ng path computation.</li>
	</ul>
	</t>
	<t>If only some of the parallel links have advertised the Bandwidth Metric:
	<ul>
	<li>The Bandwidth Metric advertisements for those links MUST be ignored.<
	/li>
	<li>Automatic metric calculation MUST be used to derive the link metrics for
	all parallel links.</li>
	</ul>
	</t>
	</list>
	</t>
	<t>This approach ensures consistent metric calculation and avoids discrepancies
	caused by partial Bandwidth Metric advertisements among parallel links.</t>	caused by partial Bandwidth Metric advertisements among parallel links.</t>

		</section>
	</section>	</section>
		</section>
	</section>	</section>
	</section>	<section anchor="sec-metric" numbered="true" toc="default">
	</section>	<name>Bandwidth Metric Considerations</name>
		<t>
	<section title='Bandwidth metric considerations' anchor='sec-metric'>
	<t>

	This section specifies the rules of deriving the Bandwidth Metric if	This section specifies the rules of deriving the Bandwidth Metric if
	and only if the winning FAD for the Flex-Algorithm specifies the	and only if the winning FAD for the Flex-Algorithm specifies the
	metric-type as "Bandwidth Metric".	metric-type as "Bandwidth Metric".

	<list>	</t>
	<t>1. If the Generic Metric sub-TLV with Bandwidth metric type	<ol type="1" spacing="normal">
	is advertised for the link as	<li>If the Generic Metric sub-TLV with Bandwidth metric-type is
	described in <xref target ='sec_bw_metric'/>,	advertised for the link as described in <xref target="sec_bw_metric"
	it MUST be used during the Flex-Algorithm	format="default"/>, it <bcp14>MUST</bcp14> be used during the
	calculation.</t>	Flex-Algorithm calculation.</li>
		<li>If the Generic Metric sub-TLV with Bandwidth metric-type is not
	<t>2. If the Generic Metric sub-TLV with Bandwidth metric type	advertised for the link and the winning FAD for the Flex-Algorithm
	is not advertised for the link	does not specify the automatic Bandwidth metric calculation (as
	and the winning FAD for the Flex-Algorithm does not specify	defined in <xref target="sec_auto_metric" format="default"/>), the
	the automatic bandwidth metric calculation (as defined in	link is treated as if the Bandwidth Metric is not available for the
	<xref target ='sec_auto_metric'/> ),	link.</li>
	the link is treated as if the Bandwidth Metric is not	<li>If the Generic Metric sub-TLV with Bandwidth metric-type is not
	available for the link.</t>	advertised for the link and the winning FAD (<xref section="5.3"
		target="RFC9350" format="default"/>) for the Flex-Algorithm specifies
	<t>3. If the Generic Metric sub-TLV with Bandwidth metric type	the automatic Bandwidth metric calculation (as defined in <xref
	is not advertised for the link	target="sec_auto_metric" format="default"/>), the Bandwidth Metric
	and the winning FAD (sec 5.3 <xref target ='RFC9350'/>	<bcp14>MUST</bcp14> be automatically calculated per the
	for the Flex-Algorithm specifies the automatic bandwidth	procedures defined in <xref target="sec_auto_metric"
	metric calculation (as defined in	format="default"/>. If the Link Bandwidth is not advertised for a
	<xref target ='sec_auto_metric'/>),	link, the link <bcp14>MUST</bcp14> be pruned for the Flex-Algorithm
	the Bandwidth Metric metric MUST be automatically calculated as per	calculations.</li>
	the procedures defined in <xref target ='sec_auto_metric'/>.	<li>In IS-IS, for Flex-Algorithm purposes, the Link Bandwidth is
	If the Link Bandwidth is not advertised for a link, the link MUST be	advertised as a sub-sub-TLV 9 of the Flex-Algorithm-specific ASLA
	pruned for the Flex-Algorithm calculations.</t>	sub-TLV. It is also possible to advertise the link bandwidth or
		Flex-Algorithm in sub-TLV 9 of TLVs 22/222/23/223/141 <xref target="RFC5
	<t>4.In ISIS the Link Bandwidth for Flex-Algorithm purposes is advertised	305"/>
	as a	together with the L-flag set in the Flex-Algorithm-specific ASLA
	sub-sub-TLV 9 of the Flex-algorithm specific ASLA sub-TLV. It is also possi	advertisement. In the absence of both of these advertisements, the
	ble	bandwidth of the link is not available for Flex-Algorithm
	to advertise the link bandwidth or Flex-Algorithm, in sub-TLV 9 of	purposes.</li>
	TLV 22/222/23/223/141 [RFC5305], together with the L-Flag set	</ol>
	in the Flex-Algorithm specific ASLA advertisement. In the absence of both
	of these advertisements, the bandwidth of the link is not available
	for Flex-Algorithm purposes.</t>

	</list>

	</t>
	</section>

	<section title='Calculation of Flex-Algorithm paths' anchor='sec-calc'>
	<t> Two new additional rules are added to the existing rules in the
	Flex-Algorithm calculations specified in Section 13 of
	<xref target ='RFC9350'/>.</t>


	<t>	</section>
	<list>	<section anchor="sec-calc" numbered="true" toc="default">
		<name>Calculation of Flex-Algorithm Paths</name>
		<t>The following two new additional rules are added to the existing rules
		in the
		Flex-Algorithm calculations specified in <xref target="RFC9350"
		sectionFormat="of" section="13"/>:</t>


	<t>6. Check if any exclude FAEMB rule is part of the Flex-Algorithm	<blockquote>
	definition. If such exclude rule exists and the link has Maximum Link	<ol spacing="normal" start="6">
	Bandwidth advertised, check if the link bandwidth satisfies the	<li>Check if any exclude FAEMB rule is part of the Flex-Algorithm
	FAEMB rule. If the link does not satisfy the FAEMB rule,	definition. If such exclude rule exists and the link has Maximum Link
	the link MUST be pruned from the Flex-Algorithm computation.</t>	Bandwidth advertised, check if the link bandwidth satisfies the FAEMB
	<t>7. Check if any exclude FAEMD rule is part of the Flex-Algorithm	rule. If the link does not satisfy the FAEMB rule, the link
	definition. If such exclude rule exists and the link has	<bcp14>MUST</bcp14> be pruned from the Flex-Algorithm computation.</li>
	Min Unidirectional link delay advertised, check if the link delay	<li>Check if any exclude FAEMD rule is part of the Flex-Algorithm
	satisfies the FAEMD rule. If the link does not satisfy the FAEMD rule,	definition. If such exclude rule exists and the link has Min
	the link MUST be pruned from the Flex-Algorithm computation.</t>	Unidirectional link delay advertised, check if the link delay
	</list>	satisfies the FAEMD rule. If the link does not satisfy the FAEMD rule,
	</t>	the link <bcp14>MUST</bcp14> be pruned from the Flex-Algorithm
		computation.</li>
		</ol>
		</blockquote>


	</section>	</section>
	<section anchor='backward_compatibility' title='Backward Compatibility'>	<section anchor="backward_compatibility" numbered="true" toc="default">
	<t> This extension brings no new backward-compatibility issues.	<name>Backward Compatibility</name>
	This document defines new FAD constraints in	<t> This extension brings no new backward-compatibility issues.
	<xref target ='sec_fad_con'/> <xref target ='sec_auto_isis'/> an	This document defines new FAD constraints in Sections
	d	<xref target="sec_fad_con" format="counter"/>, <xref target="sec
	<xref target ='sec_auto_ospf'/>. As described in <xref target =	_auto_isis" format="counter"/>, and
	'RFC9350'/>,	<xref target="sec_auto_ospf" format="counter"/>. As described in
	any node that does not understand sub-TLVs in a FAD TLV, stops p	<xref target="RFC9350" format="default"/>,
	articipation in the	any node that does not understand sub-TLVs in a FAD TLV stops pa
		rticipation in the
	corresponding Flex-Algorithm. The new extensions can be deployed among the nodes that are	corresponding Flex-Algorithm. The new extensions can be deployed among the nodes that are
	upgraded to understand the new extensions without affecting the nodes that are not upgraded.	upgraded to understand the new extensions without affecting the nodes that are not upgraded.
	This document also defines a new metric advertisement as describ ed in	This document also defines a new metric advertisement as describ ed in

	<xref target ='sec_generic_metric'/>. As per Section 13 of <xref	<xref target="sec_generic_metric" format="default"/>. As per <xr
	target ='RFC9350'/>,	ef target="RFC9350" sectionFormat="of" section="13"/>,
	the links that do not advertise the metric-type specified by the	when the links do not advertise the metric-type specified by the
	selected FAD,	selected FAD,
	the link is pruned from Flex-Algorithm calculations. The new met	the link is pruned from Flex-Algorithm calculations. The new met
	ric-types and the	ric-types and
	Flex-Algorithms using new metric-types can be deployed in the network w	Flex-Algorithms using the new metric-types can be deployed in the netwo
	ithout affecting	rk without affecting
	existing deployment. </t>	existing deployment. </t>

		</section>
	</section>	<section anchor="sec-con" numbered="true" toc="default">
	<section title='Security Considerations' anchor='sec-con'>	<name>Security Considerations</name>
	<t>This document inherits security considerations from <xref target ='RFC935	<t>This document inherits security considerations from <xref target="RFC93
	0'/>.</t>	50" format="default"/>.</t>
	</section>	</section>
		<section anchor="sec-ops" numbered="true" toc="default">
	<section title='Operational Considerations' anchor='sec-ops'>	<name>Operational Considerations</name>
	<t>Operational consideration defined in <xref target ='RFC9350'/> generally	<t>Operational considerations defined in <xref target="RFC9350" format="de
	apply to	fault"/> generally apply to
	the extensions defined in this document as well. This document defines me	the extensions defined in this document as well. This document defines a
	tric-type	metric-type
	range for user defined metrics. When user-defined metrics are used in an	range for user-defined metrics. When user-defined metrics are used in an
	inter-area or	inter-area or
	inter-level network, all the domains should assign same meaning to the pa rticular	inter-level network, all the domains should assign same meaning to the pa rticular
	metric-type. The YANG data models for Flex-Algorithm extensions are defin ed in	metric-type. The YANG data models for Flex-Algorithm extensions are defin ed in

	documents <xref target ='I-D.ietf-lsr-ospf-yang-augmentation-v1'/> and	documents <xref target="I-D.ietf-lsr-ospf-yang-augmentation-v1" format="d
	<xref target ='I-D.ietf-lsr-isis-yang-augmentation-v1'/></t>	efault"/> and
	<t>Before the router goes into maintenance activity, the traffic needs to	<xref target="I-D.ietf-lsr-isis-yang-augmentation-v1" format="default"/>.
	be diverted away	</t>
		<t>Before the router goes into maintenance activity, the traffic needs to
		be diverted away
	from the router. This is achieved by setting the overload bit or setti ng link metrics on the	from the router. This is achieved by setting the overload bit or setti ng link metrics on the

	router to a high value. In case of Generic Metric, the link metrics ca	router to a high value. In case of Generic Metric, the link metrics ca
	n be set to Maximum	n be set to a Maximum
	usable metric for OSPF and ISIS. The traffic will be diverted away fro	usable metric for OSPF and IS-IS. The traffic will be diverted away fr
	m the router to a shorter	om the router to a shorter
	available path. If there are no alternate paths available, traffic wil l stay on the router as	available path. If there are no alternate paths available, traffic wil l stay on the router as

	the links are not removed from Flex-algorithm calculation when they ar	the links are not removed from the Flex-Algorithm calculation when the
	e set to maximum metric as per	y are set to a maximum metric per
	<xref target ='RFC9350'/>	<xref target="RFC9350" format="default"/>.
	</t>	</t>
	</section>	</section>
	<section anchor="IANA" title="IANA Considerations">	<section anchor="IANA" numbered="true" toc="default">
		<name>IANA Considerations</name>
	<section anchor='igp_metric_type' title='IGP Metric-Type Registry'>	<section anchor="igp_metric_type" numbered="true" toc="default">
		<name>IGP Metric-Type Registry</name>
	<t>IGP Metric-type Registry is updated to include another column specify	<t>The "IGP Metric-Type" registry has been updated to include another co
	ing	lumn
	whether the particular metric-type is allowed in the generic-metric sub-	specifying whether the particular metric-type is allowed in the
	TLV or not.	Generic Metric sub-TLV. The range 128-255 is redefined
	The range 128-255 is being redefined in this document as user-defined ra	by this document as a user-defined range, and this range does not requir
	nge	e
	and this range does not standards action.	Standards Action <xref target="RFC8126"/>. </t>

	</t>
	<t>
	<figure anchor="iana_metric_type" title="IANA IGP Metric-Type Registry">
	<artwork>
	Type Description Reference Allowed in
	generic-metric
	----------------------------------------------------------------
	0 IGP Metric [RFC9350] No
	Section 5.1
	1 Min Unidirectional [RFC9350] No
	Link Delay as defined Section 5.1
	in [RFC8570,
	Section 4.2],and
	[RFC7471, Section 4.2]

	2 Traffic Engineering Default [RFC9350] No
	Metric as defined in Section 5.1
	[RFC5305,Section 3.7],
	and [RFC3630, Section 2.5.5]
	3(TBA) Bandwidth Metric this document yes

	128-255(TBA) User defined metric this document yes
	</artwork>
	</figure>
	</t>

	</section>
	<section anchor='isis_fad'
	title='IS-IS Sub-Sub-TLVs for Flexible Algorithm Definition Sub-TLV'>
	<t>IS-IS Sub-Sub-TLVs for Flexible Algorithm Definition Sub-TLV is part
	of the “IS-IS TLV Codepoints” registry group.</t>
	<t> Type: 6(TBD3)</t>

	<t> Description: IS-IS Exclude Minimum Bandwidth Sub-TLV </t>

	<t>Reference: This document <xref target ='sec_isis_bw_exclusion'/></t>

	<t> Type: 7 (TBD4)</t>

	<t> Description: IS-IS Exclude Maximum Delay Sub-TLV </t>

	<t>Reference: This document <xref target ='sec_isis_delay_exclusion'/></t>

	<t> Type: 8 (TBD7)</t>

	<t> Description: IS-IS Reference Bandwidth Sub-TLV </t>

	<t>Reference: This document <xref target ='sec_isis_auto_ref_bw'/></t>

	<t> Type: 9(TBD8)</t>

	<t> Description: IS-IS Threshold Metric Sub-TLV </t>

	<t>Reference: This document <xref target ='sec_isis_threshold_metric'/></t>


	</section>	<table anchor="iana_metric_type">
		<name>IGP Metric-Type Registry</name>
		<thead>
		<tr>
		<th>Type</th>
		<th>Description</th>
		<th>Reference</th>
		<th>Allowed in Generic-Metric</th>
		</tr>
		</thead>
		<tbody>
		<tr>
		<td>0</td>
		<td>IGP Metric</td>
		<td><xref target="RFC9350" sectionFormat="of" section="5.1"/></td>
		<td>No</td>
		</tr>
		<tr>
		<td>1</td>
		<td>Min Unidirectional Link Delay as defined in <xref target="RFC8570"
		sectionFormat="comma" section="4.2"/> and <xref target="RFC7471"
		sectionFormat="comma" section="4.2"/></td>
		<td><xref target="RFC9350" sectionFormat="of" section="5.1"/></td>
		<td>No</td>
		</tr>
		<tr>
		<td>2</td>
		<td>Traffic Engineering Default Metric as defined in <xref
		target="RFC5305" sectionFormat="comma" section="3.7"/> and Traffic Engine
		ering Metric as defined in <xref
		target="RFC3630" sectionFormat="comma" section="2.5.5"/></td>
		<td><xref target="RFC9350" sectionFormat="of" section="5.1"/></td>
		<td>No</td>
		</tr>
		<tr>
		<td>3</td>
		<td>Bandwidth Metric</td>
		<td>RFC 9843</td>
		<td>Yes</td>
		</tr>
		<tr>
		<td>128-255</td>
		<td>Reserved for User-Defined Metric</td>
		<td>RFC 9843</td>
		<td>Yes</td>
		</tr>
		</tbody>
		</table>
		</section>
		<section anchor="isis_fad" numbered="true" toc="default">
		<name>IS-IS Sub-Sub-TLVs for Flexible Algorithm Definition Sub-TLV</name
		>
		<t>The "IS-IS Sub-Sub-TLVs for Flexible Algorithm Definition Sub-TLV" re
		gistry is part
		of the "IS-IS TLV Codepoints" registry group.</t>


	<section anchor='ospf_fad'	<dl spacing="compact" newline="false">
	title='OSPF Sub-TLVs for Flexible Algorithm Definition Sub-TLV'>	<dt>Type:</dt><dd>6</dd>
	<t>OSPF Flexible Algorithm Definition TLV Sub-TLVs	<dt>Description:</dt><dd>IS-IS Exclude Minimum Bandwidth</dd>
	registry is part of the “Open Shortest Path First (OSPF) Parameters”	<dt>Reference:</dt><dd>RFC 9843, <xref target="sec_isis_bw_exclusion" format="
		default"/></dd>
		</dl>
		<dl spacing="compact" newline="false">
		<dt>Type:</dt><dd>7</dd>
		<dt>Description:</dt><dd>IS-IS Exclude Maximum Delay</dd>
		<dt>Reference:</dt><dd>RFC 9843, <xref target="sec_isis_delay_exclusion" forma
		t="default"/></dd>
		</dl>
		<dl spacing="compact" newline="false">
		<dt>Type:</dt><dd>8</dd>
		<dt>Description:</dt><dd>IS-IS Reference Bandwidth</dd>
		<dt>Reference:</dt><dd>RFC 9843, <xref target="sec_isis_auto_ref_bw" format="d
		efault"/></dd>
		</dl>
		<dl spacing="compact" newline="false">
		<dt>Type:</dt><dd>9</dd>
		<dt>Description:</dt><dd>IS-IS Bandwidth Threshold</dd>
		<dt>Reference:</dt><dd>RFC 9843, <xref target="sec_isis_threshold_metric" form
		at="default"/></dd>
		</dl>
		</section>
		<section anchor="ospf_fad" numbered="true" toc="default">
		<name>OSPF Sub-TLVs for Flexible Algorithm Definition Sub-TLV</name>
		<t>The "OSPF Flexible Algorithm Definition TLV Sub-TLVs"
		registry is part of the "Open Shortest Path First (OSPF) Parameters"
	registry group.</t>	registry group.</t>

		<dl spacing="compact" newline="false">
		<dt>Type:</dt><dd>6</dd>
		<dt>Description:</dt><dd>OSPF Exclude Minimum Bandwidth</dd>
		<dt>Reference:</dt><dd>RFC 9843, <xref target="sec_ospf_bw_exclusion" format="
		default"/></dd>
		</dl>
		<dl spacing="compact" newline="false">
		<dt>Type:</dt><dd>7</dd>
		<dt>Description:</dt><dd>OSPF Exclude Maximum Delay</dd>
		<dt>Reference:</dt><dd>RFC 9843, <xref target="sec_ospf_delay_exclusion" forma
		t="default"/></dd>
		</dl>
		<dl spacing="compact" newline="false">
		<dt>Type:</dt><dd>8</dd>
		<dt>Description:</dt><dd>OSPF Reference Bandwidth</dd>
		<dt>Reference:</dt><dd>RFC 9843, <xref target="sec_ospf_auto_ref_bw" format="d
		efault"/></dd>
		</dl>
		<dl spacing="compact" newline="false">
		<dt>Type:</dt><dd>9</dd>
		<dt>Description:</dt><dd>OSPF Bandwidth Threshold</dd>
		<dt>Reference:</dt><dd>RFC 9843, <xref target="sec_ospf_threshold_metric" form
		at="default"/></dd>
		</dl>
		</section>
		<section anchor="isis_gen_metric" numbered="true" toc="default">
		<name>IS-IS Sub-TLVs for TLVs Advertising Neighbor Information</name>
		<t>The "IS-IS Sub-TLVs for TLVs Advertising Neighbor Information" regist
		ry
		is part of the "IS-IS TLV Codepoints" registry group.</t>


	<t> Type:6 (TBD5)</t>	<dl spacing="compact" newline="false">
		<dt>Type:</dt><dd>17</dd>
	<t> Description: OSPF Exclude Minimum Bandwidth Sub-TLV </t>	<dt>Description:</dt><dd>Generic Metric</dd>
		<dt>TLVs set to "Y":</dt><dd>22, 23, 25, 141, 222, and 223</dd>
	<t>Reference: This document <xref target ='sec_ospf_bw_exclusion'/></t>	<dt>Reference:</dt><dd>RFC 9843, <xref target="sec_isis_gen_metric" format="de
		fault"/></dd>
	<t> Type: 7(TBD6)</t>	</dl>

	<t> Description: OSPF Exclude Maximum Delay Sub-TLV </t>

	<t>Reference: This document <xref target ='sec_ospf_delay_exclusion'/></t>

	<t> Type: 8(TBD9)</t>

	<t> Description: OSPF Reference Bandwidth Sub-TLV </t>

	<t>Reference: This document <xref target ='sec_ospf_auto_ref_bw'/></t>

	<t> Type: 9 (TBD10)</t>

	<t> Description: OSPF Threshold Metric Sub-TLV </t>

	<t>Reference: This document <xref target ='sec_ospf_threshold_metric'/></t>

	</section>
	<section anchor='isis_gen_metric'
	title='IS-IS Sub-TLVs for TLVs Advertising Neighbor Information'>
	<t>IS-IS Sub-TLVs for TLVs Advertising Neighbor Information registry
	is part of the “IS-IS TLV Codepoints” registry group</t>

	<t> Type:17 (TBD1)</t>

	<t> Description: Generic metric </t>

	<t>Reference: This document <xref target ='sec_isis_gen_metric'/></t>

	<t> TLV 22,23,25, 141, 222 and 223 set to Y</t>
	</section>
	<section anchor='isis_gen_metric_te_app'
	title='Sub-sub-TLV Codepoints for Application-Specific Link Attributes'>
	<t>IS-IS Sub-sub-TLV Codepoints for Application-Specific Link Attributes regis
	try
	is part of the “IS-IS TLV Codepoints” registry group</t>
	<t> Type: 17 (TBD1)</t>

	<t> Description: Generic metric </t>

	<t>Reference: This document <xref target ='sec_isis_gen_metric'/></t>

	</section>

	<section anchor='ospf_gen_metric' title='OSPFv2 Extended Link TLV Sub-TLVs'>
	<t> OSPFv2 Extended Link TLV Sub-TLVs registry
	is part of the “Open Shortest Path First v2 (OSPFv2) Parameters” registry grou
	p</t>
	<t> Type: 25(TBD21)</t>

	<t> Description: Generic metric </t>

	<t>Reference: This document <xref target ='sec_ospf_gen_metric'/></t>

	<t> L2BM set to Y</t>
	</section>

	<section anchor='ospf_gen_metric_te_lsa'
	title='Types for Sub-TLVs of TE Link TLV (Value 2)'>
	<t> Types for Sub-TLVs of TE Link TLV (Value 2) registry
	is part of the “Open Shortest Path First (OSPF) Traffic Engineering TLVs” regi
	stry group</t>
	<t> Type: 36 (TBD22)</t>

	<t> Description: Generic metric </t>

	<t> Reference: This document <xref target ='sec_ospf_gen_metric'/></t>

	</section>

	<section anchor='ospfv3_gen_metric_te_lsa' title='OSPFv3 Extended-LSA Sub-TLVs'
	>
	<t> OSPFv3 Extended-LSA Sub-TLVs
	is part of the “Open Shortest Path First v3 (OSPFv3) Parameters” registry grou
	p</t>
	<t> Type: 34 (TBD23)</t>

	<t> Description: Generic metric </t>

	<t> Reference: This document <xref target ='sec_ospf_gen_metric'/></t>

	<t> L2BM set to Y</t>

	</section>


	</section>	</section>
	<section title='Acknowledgements' anchor='ack'>	<section anchor="isis_gen_metric_te_app" numbered="true" toc="default">
	<t>Many thanks to Chris Bowers, Krzysztof Szarcowitz, Julian Lucek,	<name>Sub-Sub-TLV Codepoints for Application-Specific Link Attributes</n
	Ram Santhanakrishnan, Ketan Talaulikar and Acee Lindem	ame>
	for discussions and inputs.</t>	<t>The "IS-IS Sub-Sub-TLV Codepoints for Application-Specific Link Attri
	</section>	butes" registry
	<section title='Contributors'>	is part of the "IS-IS TLV Codepoints" registry group.</t>
		<dl spacing="compact" newline="false">
		<dt>Type:</dt><dd>17</dd>
		<dt>Description:</dt><dd>Generic Metric</dd>
		<dt>Reference:</dt><dd>RFC 9843, <xref target="sec_isis_gen_metric" format="de
		fault"/></dd>
		</dl>
		</section>
		<section anchor="ospf_gen_metric" numbered="true" toc="default">
		<name>OSPFv2 Extended Link TLV Sub-TLVs</name>
		<t>The "OSPFv2 Extended Link TLV Sub-TLVs" registry
		is part of the "Open Shortest Path First v2 (OSPFv2) Parameters" registry grou
		p.</t>
		<dl spacing="compact" newline="false">
		<dt>Value:</dt><dd>25</dd>
		<dt>Description:</dt><dd>Generic Metric</dd>
		<dt>L2BM:</dt><dd>Y</dd>
		<dt>Reference:</dt><dd>RFC 9843, <xref target="sec_ospf_gen_metric" format="de
		fault"/></dd>
		</dl>
		</section>
		<section anchor="ospf_gen_metric_te_lsa" numbered="true" toc="default">
		<name>Types for Sub-TLVs of TE Link TLV (Value 2)</name>
		<t>The "Types for sub-TLVs of TE Link TLV (Value 2)" registry
		is part of the "Open Shortest Path First (OSPF) Traffic Engineering TLVs" regi
		stry group.</t>
		<dl spacing="compact" newline="false">
		<dt>Value:</dt><dd>36</dd>
		<dt>Description:</dt><dd>Generic Metric</dd>
		<dt>Reference:</dt><dd>RFC 9843, <xref target="sec_ospf_gen_metric" format="de
		fault"/></dd>
		</dl>
		</section>
		<section anchor="ospfv3_gen_metric_te_lsa" numbered="true" toc="default">
		<name>OSPFv3 Extended-LSA Sub-TLVs</name>
		<t> The "OSPFv3 Extended-LSA Sub-TLVs" registry
		is part of the "Open Shortest Path First v3 (OSPFv3) Parameters" registry grou
		p.</t>
		<dl spacing="compact" newline="false">
		<dt>Value:</dt><dd>34</dd>
		<dt>Description:</dt><dd>Generic Metric</dd>
		<dt>L2BM:</dt><dd>Y</dd>
		<dt>Reference:</dt><dd>RFC 9843, <xref target="sec_ospf_gen_metric" format="de
		fault"/></dd>
		</dl>
		</section>
		</section>


	<t>1. Salih K A</t>	</middle>
	<t>Juniper Networks</t>	<back>
	<t>salih@juniper.net</t>


	</section>	<displayreference target="I-D.bashandy-rtgwg-segment-routing-uloop" to="SR-L
		OOP-AVOID"/>
		<displayreference target="I-D.ietf-lsr-isis-yang-augmentation-v1" to="ISIS-A
		UGMENTATION"/>
		<displayreference target="I-D.ietf-lsr-ospf-yang-augmentation-v1" to="OSPF-A
		UGMENTATION"/>
		<references>
		<name>References</name>
		<references>
		<name>Normative References</name>
		<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.2
		119.xml"/>
		<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8
		174.xml"/>
		<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.5
		305.xml"/>
		<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.3
		630.xml"/>
		<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.7
		684.xml"/>
		<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.9
		479.xml"/>
		<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.9
		492.xml"/>
		<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8
		362.xml"/>
		<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.9
		350.xml"/>
		<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.9
		356.xml"/>
		<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.5
		392.xml"/>
		<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.5
		329.xml"/>
		<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8
		668.xml"/>
		<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.1
		195.xml"/>
		<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.2
		328.xml"/>
		<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.81
		26.xml"/>


	<section title='APPENDIX' anchor='app'>	<reference anchor="IEEE754-2019" target="">
	<section title='Updated list of rules for pruning links in Flex-algorithm topo	<front>
	logy ' anchor='rules'>	<title>IEEE Standard for Floating-Point Arithmetic</title>
	<t>This section lists the entire set of rules to prune links from	<author>
	Flex-Algorithm topology during Flexible-algorithm calculation.	<organization>IEEE</organization>
	It includes the original rules defined in Section 13 of <xref target ='RFC9350	</author>
	'/>	<date day="22" month="July" year="2019"/>
	as well as new additions proposed in this document.	</front>
	<list>	<seriesInfo name="IEEE Std" value="754-2019"/>
	<t>For all links in the topology:</t>	<seriesInfo name="DOI" value="10.1109/ieeestd.2019.8766229"/>
	<t>1. Check if any exclude Administrative Group rule is part of the Flex-	</reference>
	Algorithm Definition.	</references>
	If such exclude rule exists, check if any color that is part of the exclu	<references>
	de rule is also set on the link.	<name>Informative References</name>
	If such a color is set, the link MUST be pruned from the computat	<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8
	ion.</t>	570.xml"/>
	<t>2. Check if any exclude SRLG rule is part of the Flex-Algorithm Definitio	<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.7
	n.	471.xml"/>
	If such exclude rule exists, check if the link is part of any SRLG that i	<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.5
	s a	311.xml"/>
	lso part of the SRLG exclude rule. If the link is part of such SRLG,	<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.9
	the link MUST be pruned from the computation.</t>	346.xml"/>
	<t>3. Check if any include-any Administrative Group rule is part	<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.5
	of the Flex-Algorithm Definition. If such include-any rule exists,	120.xml"/>
	check if any color that is part of the include-any rule is also set on th	<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.5
	e link.	715.xml"/>
	If no such color is set, the link MUST be pruned from the computation.</t	<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.4
	>	655.xml"/>
	<t>4. Check if any include-all Administrative Group rule is part of the
	Flex-Algorithm Definition. If such include-all rule exists, check if all
	colors that are part of the include-all rule are also set on the link.
	If all such colors are not set on the link, the link MUST be pruned from
	the
	computation.</t>
	<t>5. If the Flex-Algorithm Definition uses something other than the
	IGP metric (Section 5 of <xref target ='RFC9350'/>),
	and such metric is not advertised for the particular
	link in a topology for which the computation is done, such link MUST be p
	runed
	from the computation. A metric of value 0 MUST NOT be assumed in such a c
	ase.</t>
	<t>6. Check if any exclude FAEMB rule is part of the Flex-Algorithm
	definition. If such exclude rule exists and the link has Maximum Link
	Bandwidth advertised, check if the link bandwidth satisfies the
	FAEMB rule. If the link does not satisfy the FAEMB rule,
	the link MUST be pruned from the Flex-Algorithm computation.</t>
	<t>7. Check if any exclude FAEMD rule is part of the Flex-Algorithm
	definition. If such exclude rule exists and the link has
	Min Unidirectional link delay advertised, check if the link delay
	satisfies the FAEMD rule. If the link does not satisfy the FAEMD rule,
	the link MUST be pruned from the Flex-Algorithm computation.</t>


	</list>	<!-- [I-D.ietf-lsr-ospf-yang-augmentation-v1]
	</t>	draft-ietf-lsr-ospf-yang-augmentation-v1-16
	</section>	IESG State: I-D Exists as of 09/08/25.
	</section>	-->
	</middle>	<xi:include href="https://bib.ietf.org/public/rfc/bibxml3/reference.I-D.
		ietf-lsr-ospf-yang-augmentation-v1.xml"/>


	<back>	<!-- [I-D.ietf-lsr-isis-yang-augmentation-v1]
	<references title='Normative References'>	draft-ietf-lsr-isis-yang-augmentation-v1-09
		IESG State: I-D Exists as of 09/08/25.
		-->
		<xi:include href="https://bib.ietf.org/public/rfc/bibxml3/reference.I-D.
		ietf-lsr-isis-yang-augmentation-v1.xml"/>


	&RFC2119;	<!-- [I-D.bashandy-rtgwg-segment-routing-uloop]
	&RFC8174;	draft-bashandy-rtgwg-segment-routing-uloop-17
	&RFC5305;	IESG State: Expired as of 09/08/25.
	&RFC3630;	-->
	&RFC7684;	<xi:include href="https://bib.ietf.org/public/rfc/bibxml3/reference.I-D.
	&RFC9479;	bashandy-rtgwg-segment-routing-uloop.xml"/>
	&RFC9492;	</references>
	&RFC8362;	</references>
	&RFC9350;
	&RFC9356;
	&RFC5392;
	&RFC5329;
	&RFC8668;
	&RFC1195;
	&RFC2328;


	<reference anchor="IEEE754">	<section anchor="rules" numbered="true" toc="default">
	<front>	<name>Updated List of Rules for Pruning Links in Flex-Algorithm Topology<
	<title>IEEE Standard for Floating-Point Arithmetic</title>	/name>
	<author>
	<organization>Institute of Electrical and Electronics Engineers</organ
	ization>
	</author>
	<date day="22" month="July" year="2019"/>
	</front>
	<seriesInfo name="IEEE" value="754-2019"/>
	<seriesInfo name="DOI" value="10.1109/ieeestd.2019.8766229"/>
	<format target="https://ieeexplore.ieee.org/document/8766220" type="HTML"/>
	</reference>


	</references>	<t>This section lists the entire set of rules to prune links from
		Flex-Algorithm topology during Flexible Algorithm calculation. It
		includes the original rules defined in <xref target="RFC9350"
		sectionFormat="of" section="13"/> as well as the new additions (rules 6
		and 7) described in
		this document.</t>


	<references title='Informative References'>	<t>For all links in the topology:</t>
	&RFC8570;	<ol type="1" spacing="normal">
	&RFC7471;	<li>Check if any exclude Administrative Group rule is part of the
	&RFC5311;	Flex-Algorithm Definition. If such exclude rule exists, check if
	&RFC9346;	any color that is part of the exclude rule is also set on the link.
	&RFC5120;	If such a color is set, the link <bcp14>MUST</bcp14> be pruned from
	&RFC5715;	the computation.</li>
	&RFC4655;	<li>Check if any exclude SRLG rule is part of the Flex-Algorithm
	<?rfc include="reference.I-D.ietf-lsr-ospf-yang-augmentation-v1"?>	Definition. If such exclude rule exists, check if the link is part
	<?rfc include="reference.I-D.ietf-lsr-isis-yang-augmentation-v1"?>	of any SRLG that is also part of the SRLG exclude rule. If the link
		is part of such SRLG, the link <bcp14>MUST</bcp14> be pruned from
		the computation.</li>
		<li>Check if any include-any Administrative Group rule is part of
		the Flex-Algorithm Definition. If such include-any rule exists,
		check if any color that is part of the include-any rule is also set
		on the link. If no such color is set, the link <bcp14>MUST</bcp14>
		be pruned from the computation.</li>
		<li>Check if any include-all Administrative Group rule is part of
		the Flex-Algorithm Definition. If such include-all rule exists,
		check if all colors that are part of the include-all rule are also
		set on the link. If all such colors are not set on the link, the
		link <bcp14>MUST</bcp14> be pruned from the computation.</li>
		<li>If the Flex-Algorithm Definition uses something other than the
		IGP metric (<xref target="RFC9350" sectionFormat="of" section="5"/>),
		and such metric is not advertised for the particular link in a
		topology for which the computation is done, such link
		<bcp14>MUST</bcp14> be pruned from the computation. A metric of
		value 0 <bcp14>MUST NOT</bcp14> be assumed in such a case.</li>
		<li>Check if any exclude FAEMB rule is part of the Flex-Algorithm
		Definition. If such exclude rule exists and the link has Maximum
		Link Bandwidth advertised, check if the link bandwidth satisfies the
		FAEMB rule. If the link does not satisfy the FAEMB rule, the link
		<bcp14>MUST</bcp14> be pruned from the Flex-Algorithm
		computation.</li>
		<li>Check if any exclude FAEMD rule is part of the Flex-Algorithm
		Definition. If such exclude rule exists and the link has Min
		Unidirectional Link Delay advertised, check if the link delay
		satisfies the FAEMD rule. If the link does not satisfy the FAEMD
		rule, the link <bcp14>MUST</bcp14> be pruned from the Flex-Algorithm
		computation.</li>
		</ol>
		</section>
		<section anchor="ack" numbered="false" toc="default">
		<name>Acknowledgements</name>
		<t>Many thanks to <contact fullname="Chris Bowers"/>, <contact
		fullname="Krzysztof Szarcowitz"/>, <contact fullname="Julian Lucek"/>,
		<contact fullname="Ram Santhanakrishnan"/>, <contact fullname="Ketan
		Talaulikar"/>, and <contact fullname="Acee Lindem"/> for discussions and
		input.</t>
		</section>
		<section numbered="false" toc="default">
		<name>Contributors</name>


	<?rfc include="reference.I-D.bashandy-rtgwg-segment-routing-uloop"?>	<contact fullname="Salih K.A.">
		<organization>Juniper Networks</organization>
		<address>
		<email>salih@juniper.net</email>
		</address>
		</contact>
		</section>


	</references>	</back>
	</back>
	</rfc>	</rfc>

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