draft-ietf-grow-bgp-gshut-12.txt   draft-ietf-grow-bgp-gshut-13.txt 
Network Working Group P. Francois, Ed. Network Working Group P. Francois, Ed.
Internet-Draft Individual Contributor Internet-Draft Individual Contributor
Intended status: Informational B. Decraene, Ed. Intended status: Standards Track B. Decraene, Ed.
Expires: April 14, 2018 Orange Expires: June 17, 2018 Orange
C. Pelsser C. Pelsser
Strasbourg University Strasbourg University
K. Patel K. Patel
Arrcus, Inc. Arrcus, Inc.
C. Filsfils C. Filsfils
Cisco Systems Cisco Systems
October 11, 2017 December 14, 2017
Graceful BGP session shutdown Graceful BGP session shutdown
draft-ietf-grow-bgp-gshut-12 draft-ietf-grow-bgp-gshut-13
Abstract Abstract
This draft standardizes a new well-known BGP community This draft standardizes a new well-known BGP community
GRACEFUL_SHUTDOWN to signal the graceful shutdown of paths. This GRACEFUL_SHUTDOWN to signal the graceful shutdown of paths. This
draft also describes operational procedures which use this community draft also describes operational procedures which use this community
to reduce the amount of traffic lost when BGP peering sessions are to reduce the amount of traffic lost when BGP peering sessions are
about to be shut down deliberately, e.g. for planned maintenance. about to be shut down deliberately, e.g. for planned maintenance.
Status of This Memo Status of This Memo
skipping to change at page 1, line 41 skipping to change at page 1, line 41
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 14, 2018. This Internet-Draft will expire on June 17, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the Copyright (c) 2017 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 Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 23 skipping to change at page 2, line 23
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Packet loss upon manual EBGP session shutdown . . . . . . . . 3 3. Packet loss upon manual EBGP session shutdown . . . . . . . . 3
4. EBGP graceful shutdown procedure . . . . . . . . . . . . . . 4 4. EBGP graceful shutdown procedure . . . . . . . . . . . . . . 4
4.1. Pre-configuration . . . . . . . . . . . . . . . . . . . . 4 4.1. Pre-configuration . . . . . . . . . . . . . . . . . . . . 4
4.2. Operations at maintenance time . . . . . . . . . . . . . 4 4.2. Operations at maintenance time . . . . . . . . . . . . . 4
4.3. BGP implementation support for graceful shutdown . . . . 5 4.3. BGP implementation support for graceful shutdown . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . 5 6. Security Considerations . . . . . . . . . . . . . . . . . . . 5
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 5 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
8.1. Normative References . . . . . . . . . . . . . . . . . . 5 8.1. Normative References . . . . . . . . . . . . . . . . . . 6
8.2. Informative References . . . . . . . . . . . . . . . . . 6 8.2. Informative References . . . . . . . . . . . . . . . . . 6
Appendix A. Alternative techniques with limited applicability . 6 Appendix A. Alternative techniques with limited applicability . 7
A.1. Multi Exit Discriminator tweaking . . . . . . . . . . . . 6 A.1. Multi Exit Discriminator tweaking . . . . . . . . . . . . 7
A.2. IGP distance Poisoning . . . . . . . . . . . . . . . . . 7 A.2. IGP distance Poisoning . . . . . . . . . . . . . . . . . 7
Appendix B. Configuration Examples . . . . . . . . . . . . . . . 7 Appendix B. Configuration Examples . . . . . . . . . . . . . . . 7
B.1. Cisco IOS XR . . . . . . . . . . . . . . . . . . . . . . 7 B.1. Cisco IOS XR . . . . . . . . . . . . . . . . . . . . . . 7
B.2. BIRD . . . . . . . . . . . . . . . . . . . . . . . . . . 8 B.2. BIRD . . . . . . . . . . . . . . . . . . . . . . . . . . 8
B.3. OpenBGPD . . . . . . . . . . . . . . . . . . . . . . . . 8 B.3. OpenBGPD . . . . . . . . . . . . . . . . . . . . . . . . 8
Appendix C. Beyond EBGP graceful shutdown . . . . . . . . . . . 8 Appendix C. Beyond EBGP graceful shutdown . . . . . . . . . . . 9
C.1. IBGP graceful shutdown . . . . . . . . . . . . . . . . . 8 C.1. IBGP graceful shutdown . . . . . . . . . . . . . . . . . 9
C.2. EBGP session establishment . . . . . . . . . . . . . . . 8 C.2. EBGP session establishment . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction 1. Introduction
Routing changes in BGP can be caused by planned maintenance Routing changes in BGP can be caused by planned maintenance
operations. This document defines a well-known community [RFC1997], operations. This document defines a well-known community [RFC1997],
called GRACEFUL_SHUTDOWN, for the purpose of reducing the management called GRACEFUL_SHUTDOWN, for the purpose of reducing the management
overhead of gracefully shutting down BGP sessions. The well-known overhead of gracefully shutting down BGP sessions. The well-known
community allows implementers to provide an automated graceful community allows implementers to provide an automated graceful
shutdown mechanism that does not require any router reconfiguration shutdown mechanism that does not require any router reconfiguration
skipping to change at page 3, line 22 skipping to change at page 3, line 22
avoid packet loss for outbound and inbound traffic flows initially avoid packet loss for outbound and inbound traffic flows initially
forwarded along the peering link to be shut down. These procedures forwarded along the peering link to be shut down. These procedures
trigger, in both Autonomous Sytems (AS), rerouting to alternate paths trigger, in both Autonomous Sytems (AS), rerouting to alternate paths
if they exist within the AS, while allowing the use of the old path if they exist within the AS, while allowing the use of the old path
until alternate ones are learned. This ensures that routers always until alternate ones are learned. This ensures that routers always
have a valid route available during the convergence process. have a valid route available during the convergence process.
The goal of the document is to meet the requirements described in The goal of the document is to meet the requirements described in
[RFC6198] at best, without changing the BGP protocol. [RFC6198] at best, without changing the BGP protocol.
Other maintenance cases, such as the shutdown of an IBGP session or
the establishement of an EBGP session, are out of scope of this
document. For information, they are briefly discussed in Appendix C.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
document are to be interpreted as described in RFC 8174 [RFC8174]. "OPTIONAL" in this document are to be interpreted as described in
[BCP14] [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. Terminology 2. Terminology
graceful shutdown initiator: a router on which the session shutdown graceful shutdown initiator: a router on which the session shutdown
is performed for the maintenance. is performed for the maintenance.
graceful shutdown receiver: a router that has a BGP session, to be graceful shutdown receiver: a router that has a BGP session, to be
shutdown, with the graceful shutdown initiator. shutdown, with the graceful shutdown initiator.
3. Packet loss upon manual EBGP session shutdown 3. Packet loss upon manual EBGP session shutdown
skipping to change at page 4, line 17 skipping to change at page 4, line 23
This section describes configurations and actions to be performed for This section describes configurations and actions to be performed for
the graceful shutdown of EBGP peering links. the graceful shutdown of EBGP peering links.
The goal of this procedure is to retain the paths to be shutdown The goal of this procedure is to retain the paths to be shutdown
between the peers, but with a lower LOCAL_PREF value, allowing the between the peers, but with a lower LOCAL_PREF value, allowing the
paths to remain in use while alternate paths are selected and paths to remain in use while alternate paths are selected and
propagated, rather than simply withdrawing the paths. The LOCAL_PREF propagated, rather than simply withdrawing the paths. The LOCAL_PREF
value SHOULD be lower than any of the alternative paths. The value SHOULD be lower than any of the alternative paths. The
RECOMMENDED value is 0. RECOMMENDED value is 0.
Note that some alternative techniques with limited applicability are
discussed for information in Appendix A.
4.1. Pre-configuration 4.1. Pre-configuration
On each ASBR supporting the graceful shutdown receiver procedure, an On each ASBR supporting the graceful shutdown receiver procedure, an
inbound BGP route policy is applied on all EBGP sessions of the ASBR, inbound BGP route policy is applied on all EBGP sessions of the ASBR,
that: that:
o matches the GRACEFUL_SHUTDOWN community. o matches the GRACEFUL_SHUTDOWN community.
o sets the LOCAL_PREF attribute of the paths tagged with the o sets the LOCAL_PREF attribute of the paths tagged with the
GRACEFUL_SHUTDOWN community to a low value. GRACEFUL_SHUTDOWN community to a low value.
For information purpose, example of configurations are provided in
Appendix B.
4.2. Operations at maintenance time 4.2. Operations at maintenance time
On the graceful shutdown initiator, at maintenance time, the On the graceful shutdown initiator, at maintenance time, the
operator: operator:
o applies an outbound BGP route policy on the EBGP session to be o applies an outbound BGP route policy on the EBGP session to be
shutdown. This policy tags the paths propagated over the session shutdown. This policy tags the paths propagated over the session
with the GRACEFUL_SHUTDOWN community. This will trigger the BGP with the GRACEFUL_SHUTDOWN community. This will trigger the BGP
implementation to re-advertise all active routes previously implementation to re-advertise all active routes previously
advertised, and tag them with the GRACEFUL_SHUTDOWN community. advertised, and tag them with the GRACEFUL_SHUTDOWN community.
skipping to change at page 6, line 5 skipping to change at page 6, line 19
comments. comments.
8. References 8. References
8.1. Normative References 8.1. Normative References
[RFC1997] Chandra, R., Traina, P., and T. Li, "BGP Communities [RFC1997] Chandra, R., Traina, P., and T. Li, "BGP Communities
Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996, Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996,
<https://www.rfc-editor.org/info/rfc1997>. <https://www.rfc-editor.org/info/rfc1997>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC6198] Decraene, B., Francois, P., Pelsser, C., Ahmad, Z., [RFC6198] Decraene, B., Francois, P., Pelsser, C., Ahmad, Z.,
Elizondo Armengol, A., and T. Takeda, "Requirements for Elizondo Armengol, A., and T. Takeda, "Requirements for
the Graceful Shutdown of BGP Sessions", RFC 6198, the Graceful Shutdown of BGP Sessions", RFC 6198,
DOI 10.17487/RFC6198, April 2011, DOI 10.17487/RFC6198, April 2011,
<https://www.rfc-editor.org/info/rfc6198>. <https://www.rfc-editor.org/info/rfc6198>.
[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>.
 End of changes. 12 change blocks. 
15 lines changed or deleted 32 lines changed or added

This html diff was produced by rfcdiff 1.46. The latest version is available from http://tools.ietf.org/tools/rfcdiff/