draft-ietf-grow-bgp-gshut-09.txt   draft-ietf-grow-bgp-gshut-10.txt 
Network Working Group P. Francois Network Working Group P. Francois, Ed.
Internet-Draft Individual Contributor Internet-Draft Individual Contributor
Intended status: Informational B. Decraene Intended status: Informational B. Decraene, Ed.
Expires: January 4, 2018 Orange Expires: January 28, 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
July 3, 2017 July 27, 2017
Graceful BGP session shutdown Graceful BGP session shutdown
draft-ietf-grow-bgp-gshut-09 draft-ietf-grow-bgp-gshut-10
Abstract Abstract
This draft describes operational procedures aimed at reducing the This draft describes operational procedures aimed at reducing the
amount of traffic lost during planned maintenances of routers or amount of traffic lost during planned maintenances of routers or
links, involving the shutdown of BGP peering sessions. It defines a links, involving the shutdown of BGP peering sessions. It defines a
well-known BGP community, called GRACEFUL_SHUTDOWN, to signal the well-known BGP community, called GRACEFUL_SHUTDOWN, to signal the
graceful shutdown of paths. graceful shutdown of paths.
Status of This Memo Status of This Memo
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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 http://datatracker.ietf.org/drafts/current/. Drafts is at http://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 January 4, 2018. This Internet-Draft will expire on January 28, 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
(http://trustee.ietf.org/license-info) in effect on the date of (http://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
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2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Packet loss upon manual EBGP session shutdown . . . . . . . . 4 3. Packet loss upon manual EBGP session shutdown . . . . . . . . 4
4. Practices to avoid packet losses . . . . . . . . . . . . . . 4 4. Practices to avoid packet losses . . . . . . . . . . . . . . 4
4.1. Improving availability of alternate paths . . . . . . . . 4 4.1. Improving availability of alternate paths . . . . . . . . 4
4.2. Make before break convergence: graceful shutdown . . . . 5 4.2. Make before break convergence: graceful shutdown . . . . 5
4.3. Forwarding modes and transient forwarding loops during 4.3. Forwarding modes and transient forwarding loops during
convergence . . . . . . . . . . . . . . . . . . . . . . . 5 convergence . . . . . . . . . . . . . . . . . . . . . . . 5
5. EBGP graceful shutdown procedure . . . . . . . . . . . . . . 5 5. EBGP graceful shutdown procedure . . . . . . . . . . . . . . 5
5.1. Pre-configuration . . . . . . . . . . . . . . . . . . . . 5 5.1. Pre-configuration . . . . . . . . . . . . . . . . . . . . 5
5.2. Operations at maintenance time . . . . . . . . . . . . . 6 5.2. Operations at maintenance time . . . . . . . . . . . . . 6
5.3. BGP implementation support for g-Shut . . . . . . . . . . 6 5.3. BGP implementation support for graceful shutdown . . . . 6
6. Beyond EBGP graceful shutdown . . . . . . . . . . . . . . . . 7 6. Beyond EBGP graceful shutdown . . . . . . . . . . . . . . . . 7
6.1. IBGP graceful shutdown . . . . . . . . . . . . . . . . . 7 6.1. IBGP graceful shutdown . . . . . . . . . . . . . . . . . 7
6.2. Link Up cases . . . . . . . . . . . . . . . . . . . . . . 7 6.2. EBGP session establishment . . . . . . . . . . . . . . . 7
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
8. Security Considerations . . . . . . . . . . . . . . . . . . . 9 8. Security Considerations . . . . . . . . . . . . . . . . . . . 9
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
10.1. Normative References . . . . . . . . . . . . . . . . . . 9 10.1. Normative References . . . . . . . . . . . . . . . . . . 9
10.2. Informative References . . . . . . . . . . . . . . . . . 9 10.2. Informative References . . . . . . . . . . . . . . . . . 9
Appendix A. Alternative techniques with limited applicability . 10 Appendix A. Alternative techniques with limited applicability . 10
A.1. Multi Exit Discriminator tweaking . . . . . . . . . . . . 10 A.1. Multi Exit Discriminator tweaking . . . . . . . . . . . . 10
A.2. IGP distance Poisoning . . . . . . . . . . . . . . . . . 10 A.2. IGP distance Poisoning . . . . . . . . . . . . . . . . . 10
Appendix B. Configuration Examples . . . . . . . . . . . . . . . 10 Appendix B. Configuration Examples . . . . . . . . . . . . . . . 10
B.1. Cisco IOS XR . . . . . . . . . . . . . . . . . . . . . . 11 B.1. Cisco IOS XR . . . . . . . . . . . . . . . . . . . . . . 11
B.2. BIRD . . . . . . . . . . . . . . . . . . . . . . . . . . 11 B.2. BIRD . . . . . . . . . . . . . . . . . . . . . . . . . . 11
B.3. OpenBGPD . . . . . . . . . . . . . . . . . . . . . . . . 12 B.3. OpenBGPD . . . . . . . . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
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 discusses operational procedures to be operations. This document discusses operational procedures to be
applied in order to reduce or eliminate losses of packets during the applied in order to reduce or eliminate loss of packets during the
maintenance. These losses come from the transient lack of maintenance. These losses come from the transient lack of
reachability during the BGP convergence following the shutdown of an reachability during the BGP convergence following the shutdown of an
EBGP peering session between two Autonomous System Border Routers EBGP peering session between two Autonomous System Border Routers
(ASBR). (ASBR).
This document presents procedures for the cases where the forwarding This document presents procedures for the cases where the forwarding
plane is impacted by the maintenance, hence when the use of Graceful plane is impacted by the maintenance, hence when the use of Graceful
Restart does not apply. Restart does not apply.
The procedures described in this document can be applied to reduce or The procedures described in this document can be applied to reduce or
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 involved ASes, rerouting to the alternate path, trigger, in both ASes, rerouting to the alternate path if one exists
while allowing routers to keep using old paths until alternate ones within the AS, while allowing the use of the old path until alternate
are learned, installed in the RIB and in the FIB. This ensures that ones are learned. This ensures that routers always have a valid
routers always have a valid route available during the convergence route available during the convergence process.
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.
This document defines a well-known community [RFC1997], called This document defines a well-known community [RFC1997], called
GRACEFUL_SHUTDOWN, for the purpose of reducing the management 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
at maintenance time. at maintenance time.
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Loss of Connectivity (LoC: the state when a router has no path toward Loss of Connectivity (LoC: the state when a router has no path toward
an affected prefix. an affected prefix.
3. Packet loss upon manual EBGP session shutdown 3. Packet loss upon manual EBGP session shutdown
Packets can be lost during a manual shutdown of an EBGP session for Packets can be lost during a manual shutdown of an EBGP session for
two reasons. two reasons.
First, routers involved in the convergence process can transiently First, routers involved in the convergence process can transiently
lack of paths toward an affected prefix, and drop traffic destined to lack paths toward an affected prefix, and drop traffic destined to
this prefix. This is because alternate paths can be hidden by nodes this prefix. This is because alternate paths can be hidden by nodes
of an AS. This happens when the paths are not selected as best by of an AS. This happens when the paths are not selected as best by
the ASBR that receive them on an EBGP session, or by Route Reflectors the ASBR that receive them on an EBGP session, or by Route Reflectors
that do not propagate them further in the IBGP topology because they that do not propagate them further in the IBGP topology because they
do not select them as best. do not select them as best.
Second, within the AS, the FIB of routers can be transiently Second, within the AS, the FIB of routers can be transiently
inconsistent during the BGP convergence and packets toward affected inconsistent during the BGP convergence and packets toward affected
prefixes can loop and be dropped. Note that these loops only happen prefixes can loop and be dropped. Note that these loops only happen
when ASBR-to-ASBR encapsulation is not used within the AS. when ASBR-to-ASBR encapsulation is not used within the AS.
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This document only addresses the first reason. This document only addresses the first reason.
4. Practices to avoid packet losses 4. Practices to avoid packet losses
This section describes means for an ISP to reduce the transient loss This section describes means for an ISP to reduce the transient loss
of packets upon a manual shutdown of a BGP session. of packets upon a manual shutdown of a BGP session.
4.1. Improving availability of alternate paths 4.1. Improving availability of alternate paths
All solutions that increase the availability of alternate BGP paths All solutions that increase the availability of alternate BGP paths
at routers performing packet lookups in BGP tables such as at routers performing forwarding lookups from BGP routes such as
[I-D.ietf-idr-best-external] and [RFC7911] help in reducing the LoC [I-D.ietf-idr-best-external] and [RFC7911] help in reducing the LoC
bound with manual shutdown of EBGP sessions. bound with the shutdown of EBGP sessions.
One of such solutions increasing diversity in such a way that, at any Any such solution where, at any single step of the convergence
single step of the convergence process following the EBGP session process following the EBGP session shutdown, a BGP router does not
shutdown, a BGP router does not receive a message withdrawing the receive a message withdrawing the only path it currently knows for a
only path it currently knows for a given NLRI, allows for a given NLRI, allows for a simplified graceful shutdown procedure.
simplified graceful shutdown procedure.
Note that the LoC for the inbound traffic of the maintained router, Note that the LoC for the inbound traffic of graceful shutdown
induced by a lack of alternate path propagation within the IBGP initiator, due to the lack of an alternate path on the graceful
topology of a receiver AS is not under the control of the operator shutdown receiver is not under the control of the Initiator AS. The
performing the maintenance. The part of the procedure aimed at part of the procedure aimed at avoiding LoC for incoming traffic
avoiding LoC for incoming paths can thus be applied even if no LoC should thus be applied even if no LoC are expected for the outgoing
are expected for the outgoing paths. traffic.
4.2. Make before break convergence: graceful shutdown 4.2. Make before break convergence: graceful shutdown
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. propagated, rather than simply withdrawing the paths. The LOCAL_PREF
value must be lower than the one of the alternate path. 0 being the
lowest value, it can be used in all cases, except if it already has a
special meaning within the AS.
Section 5 describes configurations and actions to be performed for Section 5 describes configurations and actions to be performed for
the graceful shutdown of BGP sessions. the graceful shutdown of BGP sessions.
4.3. Forwarding modes and transient forwarding loops during convergence 4.3. Forwarding modes and transient forwarding loops during convergence
The graceful shutdown procedure or the solutions improving the The graceful shutdown procedure or the solutions improving the
availability of alternate paths, do not change the fact that BGP availability of alternate paths, do not change the fact that BGP
convergence and the subsequent FIB updates are run independently on convergence and the subsequent FIB updates are run independently on
each router of the ASes. If the AS applying the solution does not each router of the ASes. If the AS applying the solution does not
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On the graceful shutdown initiator, upon maintenance time, it is On the graceful shutdown initiator, upon maintenance time, it is
required to: required to:
o apply an outbound BGP route policy on the EBGP session to be o apply 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.
o apply an inbound BGP route policy on the maintained EBGP session o apply an inbound BGP route policy on the EBGP session to be
to tag the paths received over the session with the shutdown. This policy tags the paths received over the session
GRACEFUL_SHUTDOWN community. with the GRACEFUL_SHUTDOWN community and sets LOCAL_PREF to a low
value.
o wait for convergence to happen. o wait for convergence to happen.
o shutdown the EBGP session, optionally using o shutdown the EBGP session, optionally using
[I-D.ietf-idr-shutdown] to communicate the reason of the shutdown. [I-D.ietf-idr-shutdown] to communicate the reason of the shutdown.
In the case of a shutdown of the whole router, in addition to the In the case of a shutdown of the whole router, in addition to the
graceful shutdown of all EBGP sessions, there is a need to graceful graceful shutdown of all EBGP sessions, there is a need to graceful
shutdown the routes originated by this router (e.g, BGP aggregates shutdown the routes originated by this router (e.g, BGP aggregates
redistributed from other protocols, including static routes). This redistributed from other protocols, including static routes). This
can be performed by tagging such routes with the GRACEFUL_SHUTDOWN can be performed by tagging such routes with the GRACEFUL_SHUTDOWN
community. community and setting LOCAL_PREF to a low value.
5.3. BGP implementation support for g-Shut 5.3. BGP implementation support for graceful shutdown
A BGP router implementation MAY provide features aimed at automating A BGP router implementation MAY provide features aimed at automating
the application of the graceful shutdown procedures described above. the application of the graceful shutdown procedures described above.
Upon a session shutdown specified as graceful by the operator, a BGP Upon a session shutdown specified as graceful by the operator, a BGP
implementation supporting a graceful shutdown feature SHOULD: implementation supporting a graceful shutdown feature SHOULD:
1. Update all the paths propagated over the corresponding EBGP 1. Update all the paths propagated over the corresponding EBGP
session, tagging the GRACEFUL_SHUTDOWN community to them. Any session, tagging the GRACEFUL_SHUTDOWN community to them. Any
subsequent update sent over the session being gracefully shut subsequent update sent over the session being gracefully shut
down would be tagged with the GRACEFUL_SHUTDOWN community. down SHOULD be tagged with the GRACEFUL_SHUTDOWN community.
2. Lower the LOCAL_PREF value of the paths received over the EBGP 2. Lower the LOCAL_PREF value of the paths received over the EBGP
session being shut down. session being shut down and set the GRACEFUL_SHUTDOWN community.
3. Optionally shut down the session after a configured time. 3. Optionally shut down the session after a configured time.
4. Prevent the GRACEFUL_SHUTDOWN community from being inherited by a 4. Prevent the GRACEFUL_SHUTDOWN community from being inherited by a
path that would aggregate some paths tagged with the GSHUT path that would aggregate some paths tagged with the GSHUT
community. This behavior avoids the GSHUT procedure to be community. This behavior avoids the GSHUT procedure to be
applied to the aggregate upon the graceful shutdown of one of its applied to the aggregate upon the graceful shutdown of one of its
covered prefixes. covered prefixes.
A BGP implementation supporting a graceful shutdown feature SHOULD A BGP implementation supporting a graceful shutdown feature SHOULD
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6.1. IBGP graceful shutdown 6.1. IBGP graceful shutdown
For the shutdown of an IBGP session, provided the IBGP topology is For the shutdown of an IBGP session, provided the IBGP topology is
viable after the maintenance of the session, i.e, if all BGP speakers viable after the maintenance of the session, i.e, if all BGP speakers
of the AS have an IBGP signaling path for all prefixes advertised on of the AS have an IBGP signaling path for all prefixes advertised on
this graceful shutdown IBGP session, then the shutdown of an IBGP this graceful shutdown IBGP session, then the shutdown of an IBGP
session does not lead to transient unreachability. As a consequence, session does not lead to transient unreachability. As a consequence,
no specific graceful shutdown action is required. no specific graceful shutdown action is required.
6.2. Link Up cases 6.2. EBGP session establishment
We identify two potential causes for transient packet losses upon an We identify two potential causes for transient packet losses upon the
EBGP link up event. The first one is local to the graceful no-shut establishment of an EBGP session. The first one is local to the
initiator, the second one is due to the BGP convergence following the startup initiator, the second one is due to the BGP convergence
injection of new best paths within the IBGP topology. following the injection of new best paths within the IBGP topology.
6.2.1. Unreachability local to the ASBR 6.2.1. Unreachability local to the ASBR
An ASBR that selects as best a path received over a newly brought up An ASBR that selects as best a path received over a newly established
EBGP session may transiently drop traffic. This can typically happen EBGP session may transiently drop traffic. This can typically happen
when the NEXT_HOP attribute differs from the IP address of the EBGP when the NEXT_HOP attribute differs from the IP address of the EBGP
peer, and the receiving ASBR has not yet resolved the MAC address peer, and the receiving ASBR has not yet resolved the MAC address
associated with the IP address of that "third party" NEXT_HOP. associated with the IP address of that "third party" NEXT_HOP.
A BGP speaker implementation could avoid such losses by ensuring that A BGP speaker implementation may avoid such losses by ensuring that
"third party" NEXT_HOPs are resolved before installing paths using "third party" NEXT_HOPs are resolved before installing paths using
these in the RIB. these in the RIB.
If the link up event corresponds to an EBGP session that is being Alternatively, the operator (script) may ping third party NEXT_HOPs
manually brought up, over an already up multi-access link, then the that are expected to be used before establishing the session. By
operator can ping third party NEXT_HOP that are expected to be used proceeding like this, the MAC addresses associated with these third
before actually bringing the session up, or ping directed broadcast party NEXT_HOPs are resolved by the startup initiator.
the subnet IP address of the link. By proceeding like this, the MAC
addresses associated with these third party NEXT_HOP will be resolved
by the graceful no-shut initiator.
6.2.2. IBGP convergence 6.2.2. IBGP convergence
Corner cases leading to LoC can occur during an EBGP link up event. Corner cases leading to LoC can occur during the establishment of an
EBGP session.
A typical example for such transient unreachability for a given A typical example for such transient unreachability for a given
prefix is the following: prefix is the following:
Let's consider 3 route reflectors RR1, RR2, RR3. There is a full Let's consider 3 route reflectors RR1, RR2, RR3. There is a full
mesh of IBGP session between them. mesh of IBGP sessions between them.
1. RR1 is initially advertising the current best path to the 1. RR1 is initially advertising the current best path to the
members of its IBGP RR full-mesh. It propagated that path within members of its IBGP RR full-mesh. It propagated that path within
its RR full-mesh. RR2 knows only that path toward the prefix. its RR full-mesh. RR2 knows only that path toward the prefix.
2. RR3 receives a new best path originated by the "graceful no- 2. RR3 receives a new best path originated by the startup
shut" initiator, being one of its RR clients. RR3 selects it as initiator, being one of its RR clients. RR3 selects it as best,
best, and propagates an UPDATE within its RR full-mesh, i.e., to and propagates an UPDATE within its RR full-mesh, i.e., to RR1 and
RR1 and RR2. RR2.
3. RR1 receives that path, reruns its decision process, and picks 3. RR1 receives that path, reruns its decision process, and picks
this new path as best. As a result, RR1 withdraws its previously this new path as best. As a result, RR1 withdraws its previously
announced best-path on the IBGP sessions of its RR full-mesh. announced best-path on the IBGP sessions of its RR full-mesh.
4. If, for any reason, RR3 processes the withdraw generated in 4. If, for any reason, RR3 processes the withdraw generated in
step 3, before processing the update generated in step 2, RR3 step 3, before processing the update generated in step 2, RR3
transiently suffers from unreachability for the affected prefix. transiently suffers from unreachability for the affected prefix.
The use of [I-D.ietf-idr-best-external] among the RR of the IBGP The use of [I-D.ietf-idr-best-external] among the RR of the IBGP
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By providing the graceful shutdown service to a neighboring AS, an By providing the graceful shutdown service to a neighboring AS, an
ISP provides means to this neighbor and possibly its downstream ASes ISP provides means to this neighbor and possibly its downstream ASes
to lower the LOCAL_PREF value assigned to the paths received from to lower the LOCAL_PREF value assigned to the paths received from
this neighbor. this neighbor.
The neighbor could abuse the technique and do inbound traffic The neighbor could abuse the technique and do inbound traffic
engineering by declaring some prefixes as undergoing a maintenance so engineering by declaring some prefixes as undergoing a maintenance so
as to switch traffic to another peering link. as to switch traffic to another peering link.
If this behavior is not tolerated by the ISP, it SHOULD monitor the If this behavior is not tolerated by the ISP, it SHOULD monitor the
use of the graceful shutdown community by this neighbor. use of the graceful shutdown community.
9. Acknowledgments 9. Acknowledgments
The authors wish to thank Olivier Bonaventure, Pradosh Mohapatra and The authors wish to thank Olivier Bonaventure, Pradosh Mohapatra, Job
Job Snijders for their useful comments on this work. Snijders and John Heasley for their useful comments.
10. References 10. References
10.1. Normative References 10.1. 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,
<http://www.rfc-editor.org/info/rfc1997>. <http://www.rfc-editor.org/info/rfc1997>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
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route-policy AS64497-ebgp-inbound route-policy AS64497-ebgp-inbound
! normally this policy would contain much more ! normally this policy would contain much more
if community matches-any comm-graceful-shutdown then if community matches-any comm-graceful-shutdown then
set local-preference 0 set local-preference 0
endif endif
end-policy end-policy
! !
router bgp 64496 router bgp 64496
neighbor 2001:db8:1:2::1 neighbor 2001:db8:1:2::1
remote-as 64497 remote-as 64497
description a fantastic EBGP neighbor
address-family ipv6 unicast address-family ipv6 unicast
send-community-ebgp send-community-ebgp
route-policy AS64497-ebgp-inbound in route-policy AS64497-ebgp-inbound in
route-policy AS65040v6-bgp-out out
! !
! !
! !
B.2. BIRD B.2. BIRD
function honor_graceful_shutdown() { function honor_graceful_shutdown() {
if (65535, 0) ~ bgp_community then { if (65535, 0) ~ bgp_community then {
bgp_local_pref = 0; bgp_local_pref = 0;
} }
} }
filter AS64497_ebgp_inbound filter AS64497_ebgp_inbound
{ {
# normally this policy would contain much more # normally this policy would contain much more
honor_graceful_shutdown(); honor_graceful_shutdown();
} }
protocol bgp peer_64497_1 { protocol bgp peer_64497_1 {
description "a fantastic EBGP neighbor";
neighbor 2001:db8:1:2::1 as 64497; neighbor 2001:db8:1:2::1 as 64497;
local as 64496; local as 64496;
import keep filtered; import keep filtered;
import filter AS64497_ebgp_inbound; import filter AS64497_ebgp_inbound;
export filter AS64497_ebgp_outbound;
} }
B.3. OpenBGPD B.3. OpenBGPD
AS 64496 AS 64496
router-id 192.0.2.1 router-id 192.0.2.1
neighbor 2001:db8:1:2::1 { neighbor 2001:db8:1:2::1 {
descr "a fantastic EBGP neighbor"
remote-as 64497 remote-as 64497
} }
# normally this policy would contain much more # normally this policy would contain much more
match from any community GRACEFUL_SHUTDOWN set { localpref 0 } match from any community GRACEFUL_SHUTDOWN set { localpref 0 }
Authors' Addresses Authors' Addresses
Pierre Francois Pierre Francois (editor)
Individual Contributor Individual Contributor
Email: pfrpfr@gmail.com Email: pfrpfr@gmail.com
Bruno Decraene Bruno Decraene (editor)
Orange Orange
Email: bruno.decraene@orange.com Email: bruno.decraene@orange.com
Cristel Pelsser Cristel Pelsser
Strasbourg University Strasbourg University
Email: pelsser@unistra.fr Email: pelsser@unistra.fr
Keyur Patel Keyur Patel
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