rfc9017xml2.original.xml   rfc9017.xml 
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<rfc category="std" docName="draft-ietf-mpls-spl-terminology-06" ipr="trust20090
2" updates="3032, 7274">
<front>
<title abbrev="SPL Terminology">Special Purpose Label terminology</title> <!-- updated by Chris 02/01/21 -->
<!DOCTYPE rfc SYSTEM "rfc2629-xhtml.ent">
<rfc xmlns:xi="http://www.w3.org/2001/XInclude" docName="draft-ietf-mpls-spl-ter
minology-06" number="9017" ipr="trust200902" updates="3032, 7274" obsoletes="" s
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<!-- xml2rfc v2v3 conversion 3.5.0 -->
<front>
<title abbrev="SPL Terminology">Special-Purpose Label Terminology</title>
<seriesInfo name="RFC" value="9017"/>
<author fullname="Loa Andersson" initials="L." surname="Andersson"> <author fullname="Loa Andersson" initials="L." surname="Andersson">
<organization>Bronze Dragon Consulting</organization> <organization>Bronze Dragon Consulting</organization>
<address> <address>
<email>loa@pi.nu</email> <email>loa@pi.nu</email>
</address> </address>
</author> </author>
<author fullname="Kireeti Kompella" initials="K." surname="Kompella">
<author fullname="Kireeti Kompella" initials="K." surname="Kompella">
<organization>Juniper Networks</organization> <organization>Juniper Networks</organization>
<address> <address>
<email>kireeti@juniper.net</email> <email>kireeti@juniper.net</email>
</address> </address>
</author> </author>
<author fullname="Adrian Farrel" initials="A." surname="Farrel"> <author fullname="Adrian Farrel" initials="A." surname="Farrel">
<organization>Old Dog Consulting</organization> <organization>Old Dog Consulting</organization>
<address> <address>
<email>adrian@olddog.co.uk</email> <email>adrian@olddog.co.uk</email>
</address> </address>
</author> </author>
<date year="2021" month="April"/>
<date/> <keyword>MPLS</keyword>
<keyword>Extended Special-Purpose Label</keyword>
<workgroup>MPLS Working Group</workgroup> <keyword>Base Special-Purpose Label</keyword>
<keyword>Reserved Label</keyword>
<abstract> <keyword>Entropy Label Indicator</keyword>
<t>This document discusses and recommends a terminology that may be used when <abstract>
MPLS Special Purpose Labels (SPL) are specified and documented.</t> <t>This document discusses and recommends terminology that may be used whe
n
MPLS Special-Purpose Labels (SPLs) are specified and documented.</t>
<t>This document applies that terminology change to the relevant IANA registr y <t>This document applies that terminology change to the relevant IANA regi stry
and also clarifies the use of the Entropy Label Indicator (7) when immedia tely and also clarifies the use of the Entropy Label Indicator (7) when immedia tely
preceded by the Extension Label (15).</t> preceded by the Extension Label (15).
</t>
<t>This document updates RFC 7274 and RFC 3032.</t> <t>This document updates RFCs 3032 and 7274.</t>
</abstract>
</abstract> </front>
<middle>
</front> <section anchor="intro" numbered="true" toc="default">
<name>Introduction</name>
<middle> <t>RFC 7274 <xref target="RFC7274" format="default"/> made some changes to
the terminology
<section anchor="intro" title="Introduction"> used for MPLS Special-Purpose Labels but did not define consistent
<t>RFC 7274 <xref target="RFC7274"/> made some changes to the terminology
used for MPLS Special Purpose Labels, but did not define consistent
terminology. </t> terminology. </t>
<t>One thing that RFC 7274 did was to deprecate the use of the term
<t>One thing that RFC 7274 did was to deprecate use of the term
"reserved labels" when describing a range of labels allocated from a "reserved labels" when describing a range of labels allocated from a
registry maintained by IANA. The term "Reserved" in such a registry registry maintained by IANA. The term "Reserved" in such a registry
means "set aside, not to be used", but that range of labels was means "set aside, not to be used", but that range of labels was
available for allocation according to the policies set out in that available for allocation according to the policies set out in that
registry. The name "Special Purpose Labels" was introduced in RFC registry. The name "Special-Purpose Labels" was introduced in RFC
7274 in place of the previous term, and the abbreviation SPL was 7274 in place of the previous term, and the abbreviation "SPL" was
recommended.</t> recommended.</t>
<t>At the time of writing the first draft version of this document, the IE
<t>At the time of writing the first version of this document, the IETF was TF was in the
in the
process of allocating the very first SPLs from the Extended SPL (eSPL) process of allocating the very first SPLs from the Extended SPL (eSPL)
range <xref target="RFC8595"/>. This document discusses and recommends range <xref target="RFC8595" format="default"/>. This document discuss es and recommends
terminology and abbreviations to be used when talking about and terminology and abbreviations to be used when talking about and
documenting Special Purpose Labels.</t> documenting Special-Purpose Labels.</t>
<t>This document updates RFC 3032 <xref target="RFC3032" format="default"
<t>This document updates RFC 3032 <xref target="RFC3032"/> and RFC 7274 /> and RFC 7274
<xref target="RFC7274"/> in that it changes the terminology for both <xref target="RFC7274" format="default"/> in that it changes the termin
Base SPLs and Extended SPLs.</t> ology for both
Base SPLs (previously referred to simply as "Special-Purpose Labels") a
nd Extended SPLs.</t>
<t>This document applies that terminology change to the relevant IANA regi stry <t>This document applies that terminology change to the relevant IANA regi stry
and also clarifies the use of the Entropy Label Indicator (7) when imme diately and also clarifies the use of the Entropy Label Indicator (7) when imme diately
preceded by the Extension Label (15).</t> preceded by the Extension Label (15).</t>
<section anchor="terms" numbered="true" toc="default">
<section anchor="terms" title="Terminology"> <name>Terminology</name>
<t>The key words "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>",
<t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "<bcp14>SHALL NOT</bcp14>", "<bcp14>SHOULD</bcp14>",
"MAY", and "OPTIONAL" in this document are to be interpreted "<bcp14>SHOULD NOT</bcp14>",
as described in BCP 14 <xref target="RFC2119"/> <xref target="RFC817 "<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>",
4"/> when, "<bcp14>MAY</bcp14>", and "<bcp14>OPTIONAL</bcp14>" in this document
and only when, they appear in all capitals, as shown here.</t> are to be interpreted as described in BCP&nbsp;14
<xref target="RFC2119"/> <xref target="RFC8174"/> when, and only
when, they appear in all capitals, as shown here.</t>
</section> </section>
</section>
</section> <section anchor="bckground" numbered="true" toc="default">
<name>Background</name>
<section anchor="bckground" title="Background">
<t>Two sets of SPLs are defined for use in MPLS: <t>Two sets of SPLs are defined for use in MPLS:
<list style="symbol">
<t>The range of 0-15, Base Special Purpose Labels (bSPLs), is specifi
ed in RFC 3032
<xref target="RFC3032"/>.</t>
<t>The range 0-1048575 of eSPLs is specified in RFC 7274 <xref target
="RFC7274"/>.
<list style="symbols">
<t>the values 0-15 have been reserved never to be allocated</t>
<t>the values 16-239 are available for allocation</t>
<t>the values 240-255 are for experimental use</t>
<t>the values 256-1048575 are currently not available for
allocation. A standard track RFC will be needed to
allocate any labels from this range.</t>
</list>
</t>
</list>
</t> </t>
<ul spacing="normal">
<li>The range 0-15 (Base Special-Purpose Labels (bSPLs) as described
in this document) is specified in RFC 3032
<xref target="RFC3032" format="default"/>.</li>
<li>
<t>The range 0-1048575 of eSPLs is specified in RFC 7274 <xref target=
"RFC7274" format="default"/>.
</t>
<ul spacing="normal">
<li>The values 0-15 have been reserved and are never to be allocated
.</li>
<li>The values 16-239 are available for allocation.</li>
<li>The values 240-255 are for experimental use.</li>
<li>The values 256-1048575 are currently not available for
allocation. A Standards Track RFC would be needed to change
this rule, and that RFC would need to define the ranges that are
made available for allocation and the registration policy for those ranges.
</li>
</ul>
</li>
</ul>
<section anchor="GMPLS" numbered="true" toc="default">
<name>GMPLS Special-Purpose Labels</name>
<t>Note that IANA maintains a registry that is called "Special-Purpose G
eneralized Label Values".
Labels in that registry have special meaning when present in certain
signaling objects, are 32 bits long, and are not to be confused with
MPLS
forwarding-plane labels. This document does not make any changes to
the GMPLS
registry or to how labels from that registry are described.
<section title="GMPLS Special Purpose Labels" anchor="GMPLS"> </t>
<t>Note that IANA maintains a registry called "Special Purpose Generali
zed Label
Values". Labels in that registry have special meaning when present
in certain
signalling objects, are 32 bits long, and are not to be confused wit
h MPLS
forwarding plane labels. This document does not make any changes to
the GMPLS
registry or to how labels from that registry are described.</t>
</section> </section>
</section>
<section anchor="terminology" numbered="true" toc="default">
<name>Terminology and Abbreviations</name>
<t>
Prior to the publication of this document, IANA maintained a name space
for "Special-Purpose Multiprotocol Label Switching (MPLS) Label Values"
code points <xref target="SPL-NAME-SPACE" format="default"/>. Within this nam
e space, there are two
registries. One was called the "Special-Purpose MPLS Label Values"
registry <xref target="bSPL" format="default"/>. The other was called the "Ex
tended Special-Purpose
MPLS Label Values" registry <xref target="eSPL" format="default"/>.
</t>
</section> <t>
The difference in the name of the name space and the first registry
<section anchor="terminology" title="Terminology and Abbreviations"> is only that the MPLS abbreviation is expanded. This document makes
no change to the name of the name space itself (i.e., "Special-Purpose
<t>IANA maintains a name space for 'Special-Purpose Multiprotocol Label Multiprotocol Label Switching (MPLS) Label Values"). This document
Switching (MPLS) Label Values' code points <xref target="SPL-NAME-SPACE changes the name of the first registry to "Base Special-Purpose MPLS
"/>. Label Values" but leaves the name of the latter registry unchanged
Within this name space there are two registries. One is called the 'Spe as "Extended Special-Purpose MPLS Label Values".
cial-Purpose </t>
MPLS Label Values' registry <xref target="bSPL"/>. The other is called
'Extended Special-Purpose MPLS Label Values' registry <xref target="eSP
L"/>.</t>
<t>The difference in the name of the name space and the first registry is
only that
the MPLS abbreviation is expanded. This document changes the name of t
he first
registry to 'Base Special-Purpose MPLS Label Values', but leaves the na
me of the
latter registry unchanged as 'Extended Special-Purpose MPLS Label Value
s'.</t>
<t>The following conventions will be used in specifications and when talki ng <t>The following conventions will be used in specifications and when talki ng
about SPLs. about SPLs.
<list style="symbols">
<t>Collectively, the two (unrelated) ranges (0-15 and 16-1048575) ar
e
known as Special Purpose Labels (SPL).</t>
<t>Special purpose labels from the range 0-15 are called Base Specia
l
Purpose Labels (bSPL).</t>
<t>Special purpose labels from the range 16-1048575 are called Exten
ded
Special Purpose Labels (eSPL). (Note that the reserved values 0-
15 from the
'Extended Special-Purpose MPLS Label Values' registry do not need
a
name as they are not available for allocation and MUST NOT be use
d.)</t>
<t>The combination of the Extension Label (XL) (value 15 which is a
bSPL, and which is also called the xSPL) and an eSPL is called a
Composite Special Purpose Label (cSPL).</t>
</list>
</t> </t>
<ul spacing="normal">
<t>This results in a label stacks such as the illustrative examples shown <li>Collectively, the two (unrelated) ranges (0-15 and 16-1048575) are
in <xref target="stack-example-1"/> and <xref target="stack-example-2"/ known as "Special-Purpose Labels" (SPLs).</li>
>.</t> <li>SPLs from the range 0-15 are called "Base Special-Purpose Labels" (b
SPLs).</li>
<figure title="Example of Label Stack" align="left" anchor="stack-example- <li>SPLs from the range 16-1048575 are called "Extended
1"> Special-Purpose Labels" (eSPLs). (Note that the reserved values
<artwork align="left"> 0-15 from the
<![CDATA[ "Extended Special-Purpose MPLS Label Values" registry do not need
0 31 a
| MPLS Label Stack entry | name, as they are not available for allocation and <bcp14>MUST NOT</bcp1
+--------+--------+--------+--------+ 4> be used.)</li>
| MPLS Label Stack entry | <li>The combination of the Extension Label (XL) (value 15, which is a
+--------+--------+--------+--------+ bSPL and is also called the "xSPL") and an eSPL is called a
bSPL | Base SPL | "Composite Special-Purpose Label" (cSPL).</li>
+--------+--------+--------+--------+ </ul>
| MPLS Label Stack entry (cont.) | <t>This results in label stacks such as the examples shown
]]> in Figures&nbsp;<xref target="stack-example-1" format="counter"/> and <
</artwork> xref target="stack-example-2" format="counter"/>.</t>
<figure anchor="stack-example-1">
<name>Example of Label Stack</name>
<artwork align="left" name="" type="" alt=""><![CDATA[
0 31
| MPLS Label Stack entry |
+--------+--------+--------+--------+
| MPLS Label Stack entry |
+--------+--------+--------+--------+
bSPL | Base SPL |
+--------+--------+--------+--------+
| MPLS Label Stack entry (cont.) |]]></artwork>
</figure> </figure>
<figure anchor="stack-example-2">
<figure title="Example of Label Stack" align="left" anchor="stack-example- <name>Example of Label Stack</name>
2"> <artwork align="left" name="" type="" alt=""><![CDATA[
<artwork align="left"> 0 31
<![CDATA[ | MPLS Label Stack entry |
0 31 +--------+--------+--------+--------+
| MPLS Label Stack entry | | MPLS Label Stack entry |
+--------+--------+--------+--------+ +--------+--------+--------+--------+
| MPLS Label Stack entry | xSPL | Extension Label (XL) | <--+
+--------+--------+--------+--------+ +--------+--------+--------+--------+ |--- cSPL
xSPL | Extension Label (XL) | <--+ eSPL | Extended SPL | <--+
+--------+--------+--------+--------+ |--- cSPL +--------+--------+--------+--------+
eSPL | Extended SPL | <--+ | MPLS Label Stack entry (cont.) |]]></artwork>
+--------+--------+--------+--------+
| MPLS Label Stack entry (cont.) |
]]>
</artwork>
</figure> </figure>
</section>
</section> <section anchor="clarify" numbered="true" toc="default">
<name>Clarification on Handling of the Entropy Label Indicator</name>
<section anchor="clarify" title="Clarification on Handling of the Entropy Lab <t><xref target="RFC7274" sectionFormat="of" section="3.1"/>
el Indicator"> contains two paragraphs that describe the
<t>Section 3.1 of [RFC7274] contains two paragraphs that describe the
handling of the Entropy Label Indicator (label 7). These paragraphs ha ve introduced handling of the Entropy Label Indicator (label 7). These paragraphs ha ve introduced
some confusion about whether the Entropy Label Indicator can be present when some confusion about whether the Entropy Label Indicator can be present when
immediately preceded by the Extension Label. This document updates immediately preceded by the Extension Label. This document updates
[RFC7274] by replacing those paragraphs as follows.</t> <xref target="RFC7274"/> by replacing those paragraphs as follows.</t>
<t>OLD <t>OLD
</t>
<list style="none"> <blockquote>
<t>
<t>Values 0-15 of the "Extended Special-Purpose MPLS Label Values" Values 0-15 of the "Extended Special-Purpose MPLS Label Values"
registry are set aside as reserved. Furthermore, values 0-6 and 8-15 registry are set aside as reserved. Furthermore, values 0-6 and 8-15
MUST NOT appear in the data plane following an XL; an LSR process ing <bcp14>MUST NOT</bcp14> appear in the data plane following an XL; an LSR processing
a packet with an XL at the top of the label stack followed by a l abel a packet with an XL at the top of the label stack followed by a l abel
with value 0-6 or 8-15 MUST drop the packet.</t> with value 0-6 or 8-15 <bcp14>MUST</bcp14> drop the packet.
</t>
<t>Label 7 (when received) retains its meaning as Entropy Label <t>Label 7 (when received) retains its meaning as Entropy Label
Indicator (ELI) whether a regular special-purpose label or an ESP L; Indicator (ELI) whether a regular special-purpose label or an ESP L;
this is because of backwards compatibility with existing implemen ted this is because of backwards compatibility with existing implemen ted
and deployed code and hardware that looks for the ELI without and deployed code and hardware that looks for the ELI without
verifying if the previous label is XL or not. However, when an L SR verifying if the previous label is XL or not. However, when an L SR
inserts an entropy label, it MUST insert the ELI as a regular inserts an entropy label, it <bcp14>MUST</bcp14> insert the ELI a s a regular
special-purpose label, not as an ESPL.</t> special-purpose label, not as an ESPL.</t>
</list></t> </blockquote>
<t>NEW <t>NEW
</t>
<list style="none"> <blockquote>
<t>Values 0-15 of the "Extended Special-Purpose MPLS Label Values"
<t>Values 0-15 of the "Extended Special-Purpose MPLS Label Values"
registry are set aside as reserved. Furthermore, an implementati on registry are set aside as reserved. Furthermore, an implementati on
MUST NOT place a label with value 0-15 in the label stack immedia tely following <bcp14>MUST NOT</bcp14> place a label with a value in the range 0 -15 in the label stack immediately following
an XL; an LSR processing a packet with an XL at the top of the la bel an XL; an LSR processing a packet with an XL at the top of the la bel
stack immediately followed by a label with value 0-15 MUST drop t stack immediately followed by a label with a value in the range 0
he packet.</t> -15 <bcp14>MUST</bcp14> drop the packet.</t>
<t>When inspecting a label stack to find an Entropy Label Indicator
<t>When inspecting a label stack to find an Entropy Label Indicator (ELI -- label 7), a preexisting implementation may fail to inspec
(ELI - label 7) a pre-existing implementation may fail to inspect t the
the previous label and thus not notice that it is an XL. Such system
previous label, and so not notice that it is an XL. Such system s can
s can
continue to process the entropy information and forward the packe t when continue to process the entropy information and forward the packe t when
the previous label is an XL without causing harm. However, the p acket the previous label is an XL without causing harm. However, the p acket
will be dropped when the XL reaches the top of the stack at anoth er LSR.</t> will be dropped when the XL reaches the top of the stack at anoth er LSR.</t>
</blockquote>
</list></t>
<t>END</t> <t>END</t>
</section>
</section> <section anchor="security" numbered="true" toc="default">
<name>Security Considerations</name>
<section anchor="security" title="Security Considerations"> <t>This document describes the terminology to be used when describing and
specifying the use of SPLs. It does not affect forwarding in the MPLS
<t>The document describes the terminology to be used when describing and data plane, nor does it have any effect on how Label Switched Paths are
specifying the use of SPLs. It does not effect the forwarding in the MP established by an
LS
data plane, nor does it have any effect on how LSPs are established by
an
MPLS control plane or by a centralized controller.</t> MPLS control plane or by a centralized controller.</t>
<t>This document does not aim to describe existing implementations of SPLs or <t>This document does not aim to describe existing implementations of SPLs or
potential vulnerabilities of SPLs.</t> potential vulnerabilities of SPLs.</t>
</section>
<section anchor="IANA" numbered="true" toc="default">
<name>IANA Considerations</name>
</section> <t>IANA has changed the name of the registry once called
"Special-Purpose MPLS Label Values" to now be called "Base Special-Purp
<section anchor="IANA" title="IANA Considerations"> ose MPLS Label Values" <xref target="bSPL" format="default"/>. </t>
<t>IANA is requested to change the name of the registry that today is call
ed
"Special-Purpose MPLS Label Values" is changed to "Base Special-
Purpose MPLS Label Values". </t>
</section>
<section anchor="Acknowledgements" title="Acknowledgements">
<t>We like to thank the Routing Directorate reviwer Eric Gray
for a detailed, careful and insightful review, and Tom Petch for
pointing out several issues of clarity.</t>
</section>
<section anchor="Contributors" title="Contributors">
<t>The following people contributed text to this document:</t>
<figure>
<artwork align="left">
<![CDATA[
Stewart Bryant
Futurewei Technologies Inc.
Email: stewart.bryant@gmail.com <t>IANA has also updated the "Base Special-Purpose MPLS Label Values"
]]> registry by changing the description for value 15 from "Extension Label" t
</artwork> o
</figure> "Extension Label (XL)" and also adding this document as a reference.
</t>
</section> <table anchor="iana-reg-update-table-1">
<name>Updated Entry for Value 15 in the "Base Special-Purpose MPLS Label Value
s" Registry</name>
<thead>
<tr>
<th align="center">Value</th>
<th align="center">Description</th>
<th align="center">Reference</th>
</tr>
</thead>
<tbody>
<tr>
<td>15</td>
<td>Extension Label (XL)</td>
<td>RFC 7274, RFC 9017</td>
</tr>
</tbody>
</table>
</section>
</middle> </middle>
<back> <back>
<references>
<name>References</name>
<references>
<name>Normative References</name>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.2119.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.3032.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.7274.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.8174.xml"/>
<references title="Normative References"> <reference anchor="SPL-NAME-SPACE" target="https://www.iana.org/assignme
<?rfc include="reference.RFC.2119"?> nts/mpls-label-values/">
<?rfc include="reference.RFC.3032"?> <front>
<?rfc include="reference.RFC.7274"?> <title>Special-Purpose Multiprotocol Label Switching (MPLS) Label Va
<?rfc include="reference.RFC.8174"?> lues</title>
<author><organization>IANA</organization></author>
<reference anchor="SPL-NAME-SPACE" target="https://www.iana.org/assignment <date/>
s/mpls-label-values/mpls-label-values.xhtml/"> </front>
<front> </reference>
<title>Special-Purpose Multiprotocol Label Switching (MPLS) Label Val
ues</title>
<author/>
<date/>
</front>
</reference>
<reference anchor="bSPL" target="https://www.iana.org/assignments/mpls-lab <reference anchor="bSPL" target="https://www.iana.org/assignments/mpls-l
el-values/mpls-label-values.xhtml#special-purpose/"> abel-values/">
<front> <front>
<title>Special-Purpose MPLS Label Values</title> <title>Base Special-Purpose MPLS Label Values</title>
<author/> <author><organization>IANA</organization></author>
<date/> <date/>
</front> </front>
</reference> </reference>
<reference anchor="eSPL" target="https://www.iana.org/assignments/mpls-lab <reference anchor="eSPL" target="https://www.iana.org/assignments/mpls-l
el-values/mpls-label-values.xhtml#extended/"> abel-values/">
<front> <front>
<title>Extended Special-Purpose MPLS Label Values</title> <title>Extended Special-Purpose MPLS Label Values</title>
<author/> <author><organization>IANA</organization></author>
<date/> <date/>
</front> </front>
</reference> </reference>
</references> </references>
<references>
<references title="Informative References"> <name>Informative References</name>
<?rfc include="reference.RFC.8595"?> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.8595.xml"/>
</references>
</references> </references>
<section anchor="Acknowledgements" numbered="false" toc="default">
<name>Acknowledgements</name>
<t>We would like to thank the Routing Directorate reviewer, <contact fulln
ame="Eric Gray"/>,
for a detailed, careful, and insightful review, and <contact fullname="
Tom Petch"/> for
pointing out several issues of clarity.</t>
</section>
<section anchor="Contributors" numbered="false" toc="default">
<name>Contributors</name>
<t>The following individual contributed text to this document:</t>
<contact fullname="Stewart Bryant">
<organization>Futurewei Technologies Inc.</organization>
<address>
<postal>
<street></street>
<city></city>
<region></region>
<country></country>
</postal>
<email>stewart.bryant@gmail.com</email>
</address>
</contact>
</section>
</back> </back>
</rfc> </rfc>
 End of changes. 52 change blocks. 
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