rfc9687.original		rfc9687.txt
	IDR J. Snijders		Internet Engineering Task Force (IETF) J. Snijders
	Internet-Draft Fastly		Request for Comments: 9687 Fastly
	Updates: 4271 (if approved) B. Cartwright-Cox		Updates: 4271 B. Cartwright-Cox
	Intended status: Standards Track Port 179		Category: Standards Track Port 179
	Expires: 7 February 2025 Y. Qu		ISSN: 2070-1721 Y. Qu
	Futurewei		Futurewei
	6 August 2024		November 2024
	Border Gateway Protocol 4 (BGP-4) Send Hold Timer		Border Gateway Protocol 4 (BGP-4) Send Hold Timer
	draft-ietf-idr-bgp-sendholdtimer-15
	Abstract		Abstract
	This document defines the SendHoldtimer, along with the		This document defines the SendHoldTimer, along with the
	SendHoldTimer_Expires event, for the Border Gateway Protocol (BGP)		SendHoldTimer_Expires event, for the Border Gateway Protocol (BGP)
	Finite State Machine (FSM). Implementation of the SendHoldTimer		Finite State Machine (FSM). Implementation of the SendHoldTimer
	helps overcome situations where a BGP connection is not terminated		helps overcome situations where a BGP connection is not terminated
	after the local system detects that the remote system is not		after the local system detects that the remote system is not
	processing BGP messages. This document specifies that the local		processing BGP messages. This document specifies that the local
	system should close the BGP connection and not solely rely on the		system should close the BGP connection and not solely rely on the
	remote system for connection closure when the SendHoldTimer expires.		remote system for connection closure when the SendHoldTimer expires.
	This document updates RFC4271.		This document updates RFC 4271.
	Requirements Language
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
	"OPTIONAL" in this document are to be interpreted as described in BCP
	14 [RFC2119] [RFC8174] when, and only when, they appear in all
	capitals, as shown here.
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This is an Internet Standards Track document.
	provisions of BCP 78 and BCP 79.
	Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-
	Drafts is at https://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		This document is a product of the Internet Engineering Task Force
	and may be updated, replaced, or obsoleted by other documents at any		(IETF). It represents the consensus of the IETF community. It has
	time. It is inappropriate to use Internet-Drafts as reference		received public review and has been approved for publication by the
	material or to cite them other than as "work in progress."		Internet Engineering Steering Group (IESG). Further information on
			Internet Standards is available in Section 2 of RFC 7841.
	This Internet-Draft will expire on 7 February 2025.		Information about the current status of this document, any errata,
			and how to provide feedback on it may be obtained at
			https://www.rfc-editor.org/info/rfc9687.
	Copyright Notice		Copyright Notice
	Copyright (c) 2024 IETF Trust and the persons identified as the		Copyright (c) 2024 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents (https://trustee.ietf.org/		Provisions Relating to IETF Documents
	license-info) in effect on the date of publication of this document.		(https://trustee.ietf.org/license-info) in effect on the date of
	Please review these documents carefully, as they describe your rights		publication of this document. Please review these documents
	and restrictions with respect to this document. Code Components		carefully, as they describe your rights and restrictions with respect
	extracted from this document must include Revised BSD License text as		to this document. Code Components extracted from this document must
	described in Section 4.e of the Trust Legal Provisions and are		include Revised BSD License text as described in Section 4.e of the
	provided without warranty as described in the Revised BSD License.		Trust Legal Provisions and are provided without warranty as described
			in the Revised BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction
	2. Example of a problematic scenario . . . . . . . . . . . . . . 3		2. Requirements Language
	3. Changes to RFC 4271 - SendHoldTimer . . . . . . . . . . . . . 4		3. Example of a Problematic Scenario
	3.1. Session Attributes . . . . . . . . . . . . . . . . . . . 4		4. Changes to RFC 4271 - SendHoldTimer
	3.2. Timer Event: SendHoldTimer_Expires . . . . . . . . . . . 4		4.1. Session Attributes
	3.3. Changes to the FSM . . . . . . . . . . . . . . . . . . . 4		4.2. Timer Event: SendHoldTimer_Expires
	3.4. Changes to BGP Timers . . . . . . . . . . . . . . . . . . 6		4.3. Changes to the FSM
	4. Send Hold Timer Expired Error Handling . . . . . . . . . . . 6		4.4. Changes to BGP Timers
	5. Implementation Considerations . . . . . . . . . . . . . . . . 6		5. Send Hold Timer Expired Error Handling
	6. Operational Considerations . . . . . . . . . . . . . . . . . 7		6. Implementation Considerations
	7. Security Considerations . . . . . . . . . . . . . . . . . . . 7		7. Operational Considerations
	8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7		8. Security Considerations
	9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7		9. IANA Considerations
	10. References . . . . . . . . . . . . . . . . . . . . . . . . . 7		10. Acknowledgements
	10.1. Normative References . . . . . . . . . . . . . . . . . . 7		11. References
	10.2. Informative References . . . . . . . . . . . . . . . . . 8		11.1. Normative References
	Appendix A. Implementation status - RFC EDITOR: REMOVE BEFORE		11.2. Informative References
	PUBLICATION . . . . . . . . . . . . . . . . . . . . . . . 9		Authors' Addresses
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
	1. Introduction		1. Introduction
	This document defines the SendHoldtimer, along with the		This document defines the SendHoldTimer, along with the
	SendHoldTimer_Expires event, for the Border Gateway Protocol (BGP)		SendHoldTimer_Expires event, for the Border Gateway Protocol (BGP)
	[RFC4271] Finite State Machine (FSM) defined in section 8.		Finite State Machine (FSM) defined in Section 8 of [RFC4271].
	Failure to terminate a blocked BGP connection can result in network		Failure to terminate a blocked BGP connection can result in network
	reachability issues, and the subsequent failure to generate and		reachability issues, and the subsequent failure to generate and
	deliver BGP UPDATE messages to another BGP speaker of the local		deliver BGP UPDATE messages to another BGP speaker of the local
	system is detrimental to all participants of the inter-domain routing		system is detrimental to all participants of the inter-domain routing
	system. This phenomena is thought to have contributed to IP traffic		system. This phenomena is thought to have contributed to IP traffic
	blackholing events in the global Internet routing system		packet loss events in the global Internet routing system
	[bgpzombies].		[bgpzombies].
	This specification intends to improve this situation by requiring		This specification intends to improve this situation by requiring
	that BGP connections be terminated if the local system has detected		that BGP connections be terminated if the local system has detected
	that the remote system cannot possibly have processed any BGP		that the remote system cannot possibly have processed any BGP
	messages for the duration of the SendHoldTime. Through		messages for the duration of the SendHoldTime. Through
	standardization of the aforementioned requirement, operators will		standardization of the aforementioned requirement, operators will
	benefit from consistent behavior across different BGP		benefit from consistent behavior across different BGP
	implementations.		implementations.
	BGP speakers following this specification do not rely exclusively on		BGP speakers following this specification do not rely exclusively on
	remote systems closing blocked connections, but will also locally		remote systems closing blocked connections; they also locally close
	close blocked connections.		blocked connections.
	2. Example of a problematic scenario		2. Requirements Language
			The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
			"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
			"OPTIONAL" in this document are to be interpreted as described in
			BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
			capitals, as shown here.
			3. Example of a Problematic Scenario
	In implementations lacking the concept of a SendHoldTimer, a		In implementations lacking the concept of a SendHoldTimer, a
	malfunctioning or overwhelmed remote speaker may cause data on the		malfunctioning or overwhelmed remote speaker may cause data on the
	BGP socket in the local system to accumulate ad infinitum. This		BGP socket in the local system to accumulate ad infinitum. This
	could result in forwarding failure and traffic loss, as the		could result in forwarding failure and traffic loss, as the
	overwhelmed speaker continues to utilize stale routes.		overwhelmed speaker continues to utilize stale routes.
	An example fault state: as BGP runs over TCP [RFC9293], it is		An example fault state: as BGP runs over TCP [RFC9293], it is
	possible for a BGP speaker in the Established state to encounter a		possible for a BGP speaker in the Established state to encounter a
	BGP speaker that is advertising a TCP Receive Window (RCV.WND) of		BGP speaker that is advertising a TCP Receive Window (RCV.WND) of
	size zero. This 0 window prevents the local system from sending		size zero. The size zero of this window prevents the local system
	KEEPALIVE, UPDATE, or any other critical BGP messages across the		from sending KEEPALIVE, UPDATE, or any other critical BGP messages
	network socket to the remote speaker.		across the network socket to the remote speaker.
	Generally BGP implementations have no visibility into lower-layer		Generally BGP implementations have no visibility into lower-layer
	subsystems such as TCP or the speaker's current Receive Window size,		subsystems such as TCP or the speaker's current Receive Window size,
	and there is no existing BGP mechanism for such a blocked connection		and there is no existing BGP mechanism for such a blocked connection
	to be recognized. Hence BGP implementations are not able to handle		to be recognized. Hence BGP implementations are not able to handle
	this situation in a consistent fashion.		this situation in a consistent fashion.
	The major issue arising from a BGP speaker being unable to send a BGP		The primary issue that arises when a BGP speaker is unable to send a
	message to a given remote speaker is that as a result that speaker		BGP message to a remote speaker is that the affected speaker may end
	subsequently is operating based on stale routing information.		up operating with outdated routing information. Failure of the BGP
	Failure of the BGP speaker to send (and thus the remote speaker to		speaker to send (and thus the remote speaker to receive) BGP messages
	receive) BGP messages on a single BGP session can negatively impact		on a single BGP session can negatively impact the ability of an
	the ability of an entire autonomous system (or even a group of		entire autonomous system (or even a group of autonomous systems) to
	autonomous systems) to converge.		converge.
	3. Changes to RFC 4271 - SendHoldTimer		4. Changes to RFC 4271 - SendHoldTimer
	BGP speakers are implemented following a conceptual model "BGP Finite		BGP speakers are implemented following a conceptual model "BGP Finite
	State Machine" (FSM), which is outlined in section 8 of [RFC4271].		State Machine" (FSM), which is outlined in Section 8 of [RFC4271].
	This specification adds a BGP timer, SendHoldTimer, and updates the		This specification adds a BGP timer, SendHoldTimer, and updates the
	BGP FSM as follows:		BGP FSM as indicated in the following subsections.
	3.1. Session Attributes		4.1. Session Attributes
	The following optional session attributes for each connection are		The following optional session attributes for each connection are
	added to Section 8, before "The optional session attributes support		added to the list in Section 8 of [RFC4271] appearing just prior to
	different features of the BGP functionality that have implications		"The optional session attributes support different features of the
	for the BGP FSM state transitions":		BGP functionality that have implications for the BGP FSM state
			transitions":
	NEW		NEW
	| 14) SendHoldTimer		| 14) SendHoldTimer
	|		|
	| 15) SendHoldTime		| 15) SendHoldTime
	The SendHoldTime determines how long a BGP speaker will stay in		SendHoldTime determines how long a BGP speaker will stay in the
	Established state before the TCP connection is dropped because no BGP		Established state before the TCP connection is dropped because no BGP
	messages can be transmitted to its peer. A BGP speaker can configure		messages can be transmitted to its peer. A BGP speaker can configure
	the value of the SendHoldTime for each peer independently.		the value of the SendHoldTime for each peer independently.
	3.2. Timer Event: SendHoldTimer_Expires		4.2. Timer Event: SendHoldTimer_Expires
	Another timer event is added to Section 8.1.3 of [RFC4271] as		Another timer event is added to Section 8.1.3 of [RFC4271] as
	following:		follows:
	NEW		NEW
	| Event 29: SendHoldTimer_Expires		| Event 29: SendHoldTimer_Expires
	| Definition: An event generated when the SendHoldTimer expires.
	|		|
	| Status: Optional		| Definition: An event generated when the SendHoldTimer
			| expires.
			|
			| Status: Optional
	3.3. Changes to the FSM		4.3. Changes to the FSM
	The following changes are made to section 8.2.2 in [RFC4271].		The following changes are made to Section 8.2.2 of [RFC4271].
	In "OpenConfirm State", the handling of Event 26 is revised as		In "OpenConfirm State", the handling of Event 26 is revised as
	follows:		follows:
	OLD		OLD
	| If the local system receives a KEEPALIVE message (KeepAliveMsg		| If the local system receives a KEEPALIVE message (KeepAliveMsg
	| (Event 26)), the local system:		| (Event 26)), the local system:
	| - restarts the HoldTimer and
	|		|
	| - changes its state to Established.		| - restarts the HoldTimer and
			|
			| - changes its state to Established.
	NEW		NEW
	| If the local system receives a KEEPALIVE message (KeepAliveMsg		| If the local system receives a KEEPALIVE message (KeepAliveMsg
	| (Event 26)), the local system:		| (Event 26)), the local system:
	| - restarts the HoldTimer,
	|		|
	| - starts the SendHoldTimer if the SendHoldTime is non-zero, and		| - restarts the HoldTimer,
	|		|
	| - changes its state to Established.		| - starts the SendHoldTimer if the SendHoldTime is non-zero,
			| and
			|
			| - changes its state to Established.
	The following paragraph is added to section 8.2.2 in "Established		The following paragraph is added to Section 8.2.2 of [RFC4271] in
	State", after the paragraph which ends "unless the negotiated		"Established State", after the paragraph that ends "unless the
	HoldTime value is zero.":		negotiated HoldTime value is zero":
	NEW		NEW
	| If the SendHoldTimer_Expires (Event 29) occurs, the local		| If the SendHoldTimer_Expires (Event 29) occurs, the local system:
	| system:
	|		|
	| - (optionally) sends a NOTIFICATION message with the BGP Error		| - (optionally) sends a NOTIFICATION message with the BGP Error
	| Code "Send Hold Timer Expired" if the local system can		| Code "Send Hold Timer Expired" if the local system can
	| determine that doing so will not delay the following actions		| determine that doing so will not delay the following actions
	| in this paragraph,		| in this paragraph,
	|		|
	| - logs an error message in the local system with the BGP Error		| - logs an error message in the local system with the BGP Error
	| Code "Send Hold Timer Expired",		| Code "Send Hold Timer Expired",
	|		|
	| - releases all BGP resources,		| - releases all BGP resources,
	skipping to change at page 5, line 51 ¶		skipping to change at line 236 ¶
	|		|
	| - increments the ConnectRetryCounter by 1,		| - increments the ConnectRetryCounter by 1,
	|		|
	| - (optionally) performs peer oscillation damping if the		| - (optionally) performs peer oscillation damping if the
	| DampPeerOscillations attribute is set to TRUE, and		| DampPeerOscillations attribute is set to TRUE, and
	|		|
	| - changes its state to Idle.		| - changes its state to Idle.
	|		|
	| Each time the local system sends a BGP message, it restarts the		| Each time the local system sends a BGP message, it restarts the
	| SendHoldTimer unless the SendHoldTime value is zero or the		| SendHoldTimer unless the SendHoldTime value is zero or the
	| negotiated HoldTime value is zero, in which cases the		| negotiated HoldTime value is zero, in which case the
	| SendHoldTimer is stopped.		| SendHoldTimer is stopped.
	|		|
	| The SendHoldTimer is stopped following any transition out of		| The SendHoldTimer is stopped following any transition out of
	| the Established state as part of the "release all BGP		| the Established state as part of the "release all BGP
	| resources" action.		| resources" action.
	3.4. Changes to BGP Timers		4.4. Changes to BGP Timers
	Section 10 of [RFC4271] summarizes BGP Timers. This document adds		Section 10 of [RFC4271] summarizes BGP timers. This document adds
	another optional BGP timer: SendHoldTimer.		another optional BGP timer: SendHoldTimer.
	NEW		NEW
	| SendHoldTime is an FSM attribute that stores the initial value for		| SendHoldTime is an FSM attribute that stores the initial value for
	| the SendHoldTimer. If SendHoldTime is non-zero then it MUST be		| the SendHoldTimer. If SendHoldTime is non-zero, then it MUST be
	| greater than the value of HoldTime, see Section 5 of		| greater than the value of HoldTime; see Section 6 of [RFC9687] for
	| [I-D.ietf-idr-bgp-sendholdtimer] for suggested default values.		| suggested default values.
	4. Send Hold Timer Expired Error Handling		5. Send Hold Timer Expired Error Handling
	If the local system does not send any BGP messages within the period		If the local system does not send any BGP messages within the period
	specified in SendHoldTime, then a NOTIFICATION message with the "Send		specified in SendHoldTime, then a NOTIFICATION message with the "Send
	Hold Timer Expired" Error Code MAY be sent and the BGP connection		Hold Timer Expired" Error Code MAY be sent and the BGP connection
	MUST be closed. Additionally, an error MUST be logged in the local		MUST be closed. Additionally, an error MUST be logged in the local
	system, indicating the Send Hold Timer Expired Error Code.		system, indicating the "Send Hold Timer Expired" Error Code.
	5. Implementation Considerations		6. Implementation Considerations
	Due to the relative rarity of the failure mode that this		Due to the relative rarity of the failure mode that this
	specification is designed to address, and also the fact that network		specification is designed to address, and also the fact that network
	operators may be unfamiliar with the formal specification of BGP		operators may be unfamiliar with the formal specification of BGP
	fault detection mechanisms such as HoldTimer, it is likely that a		fault detection mechanisms such as HoldTimer, it is likely that a
	large number of operators are unaware of the necessity of an		large number of operators will be unaware of the need for an
	additional mechanism such as SendHoldtimer.		additional mechanism such as SendHoldTimer.
	Accordingly, it is RECOMMENDED that implementations of this		Accordingly, it is RECOMMENDED that implementations of this
	specification enable SendHoldtimer by default, without requiring		specification enable SendHoldTimer by default, without requiring
	additional configuration of the BGP speaking device.		additional configuration of the BGP-speaking device.
	The default value of SendHoldTime for a BGP connection SHOULD be the		The default value of SendHoldTime for a BGP connection SHOULD be the
	greater of:		greater of:
	* 8 minutes; or		* 8 minutes or
	* 2 times the negotiated HoldTime		* 2 times the negotiated HoldTime
	Implementations MAY make the value of SendHoldTime configurable,		Implementations MAY make the value of SendHoldTime configurable,
	either globally or on a per-peer basis, within the constraints set		either globally or on a per-peer basis, within the constraints set
	out in Section 3.4 above.		out in Section 4.4.
	The subcode for NOTIFICATION message "Send Hold Timer Expired" is set		The subcode for NOTIFICATION message "Send Hold Timer Expired" is set
	to 0 and is not used, no additional data is to be appended to the end		to 0 and is not used; no additional data is to be appended to the end
	of a "Send Hold Timer Expired" NOTIFICATION message.		of a "Send Hold Timer Expired" NOTIFICATION message.
	6. Operational Considerations		7. Operational Considerations
	When the local system recognizes a remote speaker is not processing		When the local system recognizes that a remote speaker has not
	any BGP messages for the duration of the SendHoldTime, it is likely		processed any BGP messages for the duration of the SendHoldTime, it
	that the local system will not be able to inform the remote peer		is likely that the local system will not be able to inform the remote
	through a NOTIFICATION message as to why the connection is being		peer through a NOTIFICATION message as to why the connection is being
	closed. This documents suggests that an attempt to send a		closed. This document suggests that an attempt to send a
	NOTIFICATION message with the "Send Hold Timer Expired" error code is		NOTIFICATION message with the "Send Hold Timer Expired" Error Code
	still made, if doing so will not delay closing the BGP connection.		still be made, if doing so will not delay closing the BGP connection.
	Meanwhile an error message is logged into the local system.		Meanwhile, an error message is logged in the local system.
	Other mechanisms can be used as well, for example BGP speakers SHOULD		Other mechanisms can be used as well, for example, BGP speakers
	provide this reason as part of their operational state; e.g.		SHOULD provide this reason ("Send Hold Timer Expired") as part of
	bgpPeerLastError in the BGP MIB [RFC4273].		their operational state (for example, bgpPeerLastError in the BGP MIB
			[RFC4273]).
	7. Security Considerations		8. Security Considerations
	This specification does not change BGP's security characteristics.		This specification does not change BGP's security characteristics.
	Implementing the BGP SendHoldTimer as specified in this document will		Implementing the BGP SendHoldTimer as specified in this document will
	enhance network resilience by terminating connections with		enhance network resilience by terminating connections with
	malfunctioning or overwhelmed remote peers.		malfunctioning or overwhelmed remote peers.
	8. IANA Considerations		9. IANA Considerations
	IANA has registered code 8 for "Send Hold Timer Expired" in the "BGP		IANA has registered value 8 for "Send Hold Timer Expired" in the "BGP
	Error (Notification) Codes" registry in the "Border Gateway Protocol		Error (Notification) Codes" registry within the "Border Gateway
	(BGP) Parameters" registry group.		Protocol (BGP) Parameters" registry group.
	9. Acknowledgements		10. Acknowledgements
	The authors would like to thank William McCall, Theo de Raadt, John		The authors would like to thank William McCall, Theo de Raadt, John
	Heasley, Nick Hilliard, Jeffrey Haas, Tom Petch, Susan Hares, Keyur		Heasley, Nick Hilliard, Jeffrey Haas, Tom Petch, Susan Hares, Keyur
	Patel, Ben Maddison, Claudio Jeker, and John Scudder for their		Patel, Ben Maddison, Claudio Jeker, and John Scudder for their
	helpful review of this document.		helpful review of this document.
	10. References		11. References
	10.1. Normative References
	[I-D.ietf-idr-bgp-sendholdtimer]		11.1. Normative References
	Snijders, J., Cartwright-Cox, B., and Y. Qu, "Border
	Gateway Protocol 4 (BGP-4) Send Hold Timer", Work in
	Progress, Internet-Draft, draft-ietf-idr-bgp-
	sendholdtimer, <https://datatracker.ietf.org/doc/html/
	draft-ietf-idr-bgp-sendholdtimer>.
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119,		Requirement Levels", BCP 14, RFC 2119,
	DOI 10.17487/RFC2119, March 1997,		DOI 10.17487/RFC2119, March 1997,
	<https://www.rfc-editor.org/info/rfc2119>.		<https://www.rfc-editor.org/info/rfc2119>.
	[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A		[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
	Border Gateway Protocol 4 (BGP-4)", RFC 4271,		Border Gateway Protocol 4 (BGP-4)", RFC 4271,
	DOI 10.17487/RFC4271, January 2006,		DOI 10.17487/RFC4271, January 2006,
	<https://www.rfc-editor.org/info/rfc4271>.		<https://www.rfc-editor.org/info/rfc4271>.
	[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC		[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
	2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,		2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
	May 2017, <https://www.rfc-editor.org/info/rfc8174>.		May 2017, <https://www.rfc-editor.org/info/rfc8174>.
	[RFC9293] Eddy, W., Ed., "Transmission Control Protocol (TCP)",		[RFC9293] Eddy, W., Ed., "Transmission Control Protocol (TCP)",
	RFC 9293, DOI 10.17487/RFC9293, August 2022,		STD 7, RFC 9293, DOI 10.17487/RFC9293, August 2022,
	<https://www.rfc-editor.org/info/rfc9293>.		<https://www.rfc-editor.org/info/rfc9293>.
	10.2. Informative References		11.2. Informative References
	[bgpzombies]		[bgpzombies]
	Fontugne, R., "BGP Zombies", April 2019,		Fontugne, R., "BGP Zombies", April 2019,
	<https://labs.ripe.net/author/romain_fontugne/bgp-		<https://labs.ripe.net/author/romain_fontugne/bgp-
	zombies/>.		zombies/>.
	[BIRD] Kubecova, K., "BIRD Internet Routing Daemon", October
	2023, <https://gitlab.nic.cz/labs/bird/-/commit/
	bcf2327425d4dd96f381b87501cccf943bed606e>.
	[frr] Lamparter, D., "bgpd: implement SendHoldTimer", May 2022,
	<https://github.com/FRRouting/frr/pull/11225>.
	[neo-bgp] Cartwright-Cox, B., "What does bgp.tools support", August
	2022, <https://bgp.tools/kb/bgp-support>.
	[openbgpd] Jeker, C., "bgpd send side hold timer", December 2020,
	<https://marc.info/?l=openbsd-tech&m=160820754925261&w=2>.
	[RFC4273] Haas, J., Ed. and S. Hares, Ed., "Definitions of Managed		[RFC4273] Haas, J., Ed. and S. Hares, Ed., "Definitions of Managed
	Objects for BGP-4", RFC 4273, DOI 10.17487/RFC4273,		Objects for BGP-4", RFC 4273, DOI 10.17487/RFC4273,
	January 2006, <https://www.rfc-editor.org/info/rfc4273>.		January 2006, <https://www.rfc-editor.org/info/rfc4273>.
	Appendix A. Implementation status - RFC EDITOR: REMOVE BEFORE
	PUBLICATION
	This section records the status of known implementations of the
	protocol defined by this specification at the time of posting of this
	Internet-Draft, and is based on a proposal described in RFC 7942.
	The description of implementations in this section is intended to
	assist the IETF in its decision processes in progressing drafts to
	RFCs. Please note that the listing of any individual implementation
	here does not imply endorsement by the IETF. Furthermore, no effort
	has been spent to verify the information presented here that was
	supplied by IETF contributors. This is not intended as, and must not
	be construed to be, a catalog of available implementations or their
	features. Readers are advised to note that other implementations may
	exist.
	According to RFC 7942, "this will allow reviewers and working groups
	to assign due consideration to documents that have the benefit of
	running code, which may serve as evidence of valuable experimentation
	and feedback that have made the implemented protocols more mature.
	It is up to the individual working groups to use this information as
	they see fit".
	* OpenBGPD [openbgpd]
	* FRRouting [frr]
	* neo-bgp (bgp.tools) [neo-bgp]
	* BIRD [BIRD]
	Patches to recognize error code 8 were merged into OpenBSD's and the-
	tcpdump-group's tcpdump implementations.
	Authors' Addresses		Authors' Addresses
	Job Snijders		Job Snijders
	Fastly		Fastly
	Amsterdam		Amsterdam
	Netherlands		Netherlands
	Email: job@fastly.com		Email: job@fastly.com
	Ben Cartwright-Cox		Ben Cartwright-Cox
	Port 179 Ltd		Port 179 Ltd
	skipping to change at page 10, line 4 ¶		skipping to change at line 373 ¶
	Fastly		Fastly
	Amsterdam		Amsterdam
	Netherlands		Netherlands
	Email: job@fastly.com		Email: job@fastly.com
	Ben Cartwright-Cox		Ben Cartwright-Cox
	Port 179 Ltd		Port 179 Ltd
	London		London
	United Kingdom		United Kingdom
	Email: ben@benjojo.co.uk		Email: ben@benjojo.co.uk
	Yingzhen Qu		Yingzhen Qu
	Futurewei Technologies		Futurewei Technologies
	Santa Clara,		San Jose, CA 95131
	United States		United States of America
	Email: yingzhen.ietf@gmail.com		Email: yingzhen.ietf@gmail.com
End of changes. 64 change blocks.
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