draft-ietf-idr-bgp-optimal-route-reflection-25.txt   draft-ietf-idr-bgp-optimal-route-reflection-26.txt 
IDR Working Group R. Raszuk, Ed. IDR Working Group R. Raszuk, Ed.
Internet-Draft NTT Network Innovations Internet-Draft NTT Network Innovations
Intended status: Standards Track B. Decraene, Ed. Updates: 4456 (if approved) B. Decraene, Ed.
Expires: December 16, 2021 Orange Intended status: Standards Track Orange
C. Cassar Expires: December 18, 2021 C. Cassar
E. Aman E. Aman
K. Wang K. Wang
Juniper Networks Juniper Networks
June 14, 2021 June 16, 2021
BGP Optimal Route Reflection (BGP-ORR) BGP Optimal Route Reflection (BGP ORR)
draft-ietf-idr-bgp-optimal-route-reflection-25 draft-ietf-idr-bgp-optimal-route-reflection-26
Abstract Abstract
This document defines an extension to BGP route reflectors. On route This document defines an extension to BGP route reflectors. On route
reflectors, BGP route selection is modified in order to choose the reflectors, BGP route selection is modified in order to choose the
best route from the standpoint of their clients, rather than from the best route from the standpoint of their clients, rather than from the
standpoint of the route reflectors. Depending on the scaling and standpoint of the route reflectors. Depending on the scaling and
precision requirements, route selection can be specific for one precision requirements, route selection can be specific for one
client, common for a set of clients or common for all clients of a client, common for a set of clients or common for all clients of a
route reflector. This solution is particularly applicable in route reflector. This solution is particularly applicable in
deployments using centralized route reflectors, where choosing the deployments using centralized route reflectors, where choosing the
best route based on the route reflector's IGP location is suboptimal. best route based on the route reflector's Interior Gateway Protocol
This facilitates, for example, best exit point policy (hot potato (IGP) location is suboptimal. This facilitates, for example, best
routing). exit point policy (hot potato routing).
The solution relies upon all route reflectors learning all paths The solution relies upon all route reflectors learning all paths
which are eligible for consideration. BGP Route Selection is which are eligible for consideration. BGP Route Selection is
performed in the route reflectors based on the IGP cost from performed in the route reflectors based on the IGP cost from
configured locations in the link state IGP. configured locations in the link state IGP.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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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 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 December 16, 2021. This Internet-Draft will expire on December 18, 2021.
Copyright Notice Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the Copyright (c) 2021 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 36 skipping to change at page 2, line 36
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Modifications to BGP Route Selection . . . . . . . . . . . . 4 3. Modifications to BGP Route Selection . . . . . . . . . . . . 4
3.1. Route Selection from a different IGP location . . . . . . 5 3.1. Route Selection from a different IGP location . . . . . . 5
3.1.1. Restriction when BGP next hop is a BGP prefix . . . . 6 3.1.1. Restriction when BGP next hop is a BGP prefix . . . . 6
3.2. Multiple Route Selections . . . . . . . . . . . . . . . . 6 3.2. Multiple Route Selections . . . . . . . . . . . . . . . . 6
4. Deployment Considerations . . . . . . . . . . . . . . . . . . 6 4. Deployment Considerations . . . . . . . . . . . . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . 8 5. Security Considerations . . . . . . . . . . . . . . . . . . . 8
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 8 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 8
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 8 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 9
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
9.1. Normative References . . . . . . . . . . . . . . . . . . 9 9.1. Normative References . . . . . . . . . . . . . . . . . . 9
9.2. Informative References . . . . . . . . . . . . . . . . . 9 9.2. Informative References . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction 1. Introduction
There are three types of BGP deployments within Autonomous Systems There are three types of BGP (Border Gateway Protocol) deployments
today: full mesh, confederations and route reflection. BGP route within Autonomous Systems today: full mesh, confederations and route
reflection [RFC4456] is the most popular way to distribute BGP routes reflection. BGP route reflection [RFC4456] is the most popular way
between BGP speakers belonging to the same Autonomous System. to distribute BGP routes between BGP speakers belonging to the same
However, in some situations, this method suffers from non-optimal Autonomous System. However, in some situations, this method suffers
path selection. from non-optimal path selection.
[RFC4456] asserts that, because the IGP cost to a given point in the [RFC4456] asserts that, because the IGP cost to a given point in the
network will vary across routers, "the route reflection approach may network will vary across routers, "the route reflection approach may
not yield the same route selection result as that of the full IBGP not yield the same route selection result as that of the full
mesh approach." One practical implication of this assertion is that Internal BGP (IBGP) mesh approach." One practical implication of
the deployment of route reflection may thwart the ability to achieve this fact is that the deployment of route reflection may thwart the
hot potato routing. Hot potato routing attempts to direct traffic to ability to achieve hot potato routing. Hot potato routing attempts
the closest AS exit point in cases where no higher priority policy to direct traffic to the closest Autonomous System (AS) exit point in
dictates otherwise. As a consequence of the route reflection method, cases where no higher priority policy dictates otherwise. As a
the choice of exit point for a route reflector and its clients will consequence of the route reflection method, the choice of exit point
be the exit point that is optimal for the route reflector - not for a route reflector and its clients will be the exit point that is
necessarily the one that is optimal for its clients. optimal for the route reflector - not necessarily the one that is
optimal for its clients.
Section 11 of [RFC4456] describes a deployment approach and a set of Section 11 of [RFC4456] describes a deployment approach and a set of
constraints which, if satisfied, would result in the deployment of constraints which, if satisfied, would result in the deployment of
route reflection yielding the same results as the IBGP full mesh route reflection yielding the same results as the IBGP full mesh
approach. This deployment approach makes route reflection compatible approach. This deployment approach makes route reflection compatible
with the application of hot potato routing policy. In accordance with the application of hot potato routing policy. In accordance
with these design rules, route reflectors have often been deployed in with these design rules, route reflectors have often been deployed in
the forwarding path and carefully placed on the POP to core the forwarding path and carefully placed on the Point of Presence
boundaries. (POP) to core boundaries.
The evolving model of intra-domain network design has enabled The evolving model of intra-domain network design has enabled
deployments of route reflectors outside the forwarding path. deployments of route reflectors outside the forwarding path.
Initially this model was only employed for new services, e.g., IP Initially this model was only employed for new services, e.g., IP
VPNs [RFC4364], however it has been gradually extended to other BGP VPNs [RFC4364], however it has been gradually extended to other BGP
services, including the IPv4 and IPv6 Internet. In such services, including the IPv4 and IPv6 Internet. In such
environments, hot potato routing policy remains desirable. environments, hot potato routing policy remains desirable.
Route reflectors outside the forwarding path can be placed on the POP Route reflectors outside the forwarding path can be placed on the POP
to core boundaries, but they are often placed in arbitrary locations to core boundaries, but they are often placed in arbitrary locations
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14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
3. Modifications to BGP Route Selection 3. Modifications to BGP Route Selection
The core of this solution is the ability for an operator to specify The core of this solution is the ability for an operator to specify
the IGP location for which the route reflector calculates interior the IGP location for which the route reflector calculates interior
cost for the NEXT_HOP. The IGP location is defined as a node in the cost for the NEXT_HOP. The IGP location is defined as a node in the
IGP topology, it is identified by an IP address of this node (e.g., a IGP topology, it is identified by an IP address of this node (e.g., a
loopback address), and may be configured on a per route reflector loopback address), and may be configured on a per route reflector
basis, per set of clients, or per client basis. This ability enables basis, per set of clients, or per client basis. Such configuration
the route reflector to send to a given set of clients routes with will allow the route reflector to select and distribute to a given
shortest distance to the next hops from the position of the selected set of clients routes with shortest distance to the next hops from
IGP location. This provides for freedom of route reflector physical the position of the selected IGP location. This provides for freedom
location, and allows transient or permanent migration of this network of route reflector physical location, and allows transient or
control plane function to an arbitrary location. permanent migration of this network control plane function to an
arbitrary location with no impact to IP transit.
The choice of specific granularity (route reflector, set of clients, The choice of specific granularity (route reflector, set of clients,
or client) is configured by the network operator. An implementation or client) is configured by the network operator. An implementation
is considered compliant with this document if it supports at least is considered compliant with this document if it supports at least
one listed grouping of IGP location. one such grouping category.
For purposes of route selection, the perspective of a client can For purposes of route selection, the perspective of a client can
differ from that of a route reflector or another client in two differ from that of a route reflector or another client in two
distinct ways: distinct ways:
o it has a different position in the IGP topology, o it has a different position in the IGP topology,
o it can have a different routing policy. o it can have a different routing policy.
These factors correspond to the issues described earlier. These factors correspond to the issues described earlier.
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interior cost. The interior cost of a route is determined by interior cost. The interior cost of a route is determined by
calculating the metric from the selected IGP location to the calculating the metric from the selected IGP location to the
NEXT_HOP for the route using the shortest IGP path tree rooted at NEXT_HOP for the route using the shortest IGP path tree rooted at
the selected IGP location. the selected IGP location.
In order to be able to compute the shortest path tree rooted at the In order to be able to compute the shortest path tree rooted at the
selected IGP locations, knowledge of the IGP topology for the area/ selected IGP locations, knowledge of the IGP topology for the area/
level that includes each of those locations is needed. This level that includes each of those locations is needed. This
knowledge can be gained with the use of the link state IGP such as knowledge can be gained with the use of the link state IGP such as
IS-IS [ISO10589] or OSPF [RFC2328] [RFC5340] or via BGP-LS [RFC7752]. IS-IS [ISO10589] or OSPF [RFC2328] [RFC5340] or via BGP-LS [RFC7752].
One or more backup IGP locations SHOULD be allowed to be specified When specifing logical location of a route reflector for a group of
for redundancy. clients one or more backup IGP locations SHOULD be allowed to be
specified for redundancy. Further deployment considerations are
discussed in Section 4.
3.1.1. Restriction when BGP next hop is a BGP prefix 3.1.1. Restriction when BGP next hop is a BGP prefix
In situations where the BGP next hop is a BGP prefix itself, the IGP In situations where the BGP next hop is a BGP route itself, the IGP
metric of a route used for its resolution SHOULD be the final IGP metric of a route used for its resolution SHOULD be the final IGP
cost to reach such next hop. Implementations which cannot inform BGP cost to reach such next hop. Implementations which cannot inform BGP
of the final IGP metric to a recursive next hop MUST treat such paths of the final IGP metric to a recursive next hop MUST treat such paths
as least preferred during next hop metric comparison. However, such as least preferred during next hop metric comparison. However, such
paths MUST still be considered valid for BGP Phase 2 Route Selection. paths MUST still be considered valid for BGP Phase 2 Route Selection.
3.2. Multiple Route Selections 3.2. Multiple Route Selections
BGP Route Reflector as per [RFC4456] runs a single BGP Decision BGP Route Reflector as per [RFC4456] runs a single BGP Decision
Process. Optimal route reflection may require multiple BGP Decision Process. Optimal route reflection may require multiple BGP Decision
Processes or subsets of the Decision Process in order to consider Processes or subsets of the Decision Process in order to consider
different IGP locations or BGP policies for different sets of different IGP locations or BGP policies for different sets of
clients. clients. This is very similar to what is defined in [RFC7947]
section 2.3.2.1.
If the required routing optimization is limited to the IGP cost to If the required routing optimization is limited to the IGP cost to
the BGP Next-Hop, only step e) and below as defined [RFC4271] section the BGP Next-Hop, only step e) and subsequent steps as defined in
9.1.2.2, needs to be run multiple times. [RFC4271] section 9.1.2.2, needs to be run multiple times.
If the routing optimization requires the use of different BGP If the routing optimization requires the use of different BGP
policies for different sets of clients, a larger part of the decision policies for different sets of clients, a larger part of the decision
process needs to be run multiple times, up to the whole decision process needs to be run multiple times, up to the whole decision
process as defined in section 9.1 of [RFC4271]. This is for example process as defined in section 9.1 of [RFC4271]. This is for example
the case when there is a need to use different policies to compute the case when there is a need to use different policies to compute
different degree of preference during Phase 1. This is needed for different degree of preference during Phase 1. This is needed for
use cases involving traffic engineering or dedicating certain exit use cases involving traffic engineering or dedicating certain exit
points for certain clients. In the latter case, the user may specify points for certain clients. In the latter case, the user may specify
and apply a general policy on the route reflector for a set of and apply a general policy on the route reflector for a set of
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A route reflector can implement either or both of the modifications A route reflector can implement either or both of the modifications
in order to allow it to choose the best path for its clients that the in order to allow it to choose the best path for its clients that the
clients themselves would have chosen given the same set of candidate clients themselves would have chosen given the same set of candidate
paths. paths.
4. Deployment Considerations 4. Deployment Considerations
BGP Optimal Route Reflection provides a model for integrating the BGP Optimal Route Reflection provides a model for integrating the
client perspective into the BGP Route Selection decision function for client perspective into the BGP Route Selection decision function for
route reflectors. More specifically, the choice of BGP path factors route reflectors. More specifically, the choice of BGP path takes
in either the IGP cost between the client and the NEXT_HOP (rather into account either the IGP cost between the client and the NEXT_HOP
than the IGP cost from the route reflector to the NEXT_HOP) or other (rather than the IGP cost from the route reflector to the NEXT_HOP)
user configured policies. or other user configured policies.
The achievement of optimal routing between clients of different The achievement of optimal routing between clients of different
clusters relies upon all route reflectors learning all paths that are clusters relies upon all route reflectors learning all paths that are
eligible for consideration. In order to satisfy this requirement, eligible for consideration. In order to satisfy this requirement,
BGP add-path [RFC7911] needs to be deployed between route reflectors. BGP add-path [RFC7911] needs to be deployed between route reflectors.
This solution can be deployed in traditional hop-by-hop forwarding This solution can be deployed in traditional hop-by-hop forwarding
networks as well as in end-to-end tunneled environments. In networks networks as well as in end-to-end tunneled environments. In networks
where there are multiple route reflectors and hop-by-hop forwarding where there are multiple route reflectors and hop-by-hop forwarding
without encapsulation, such optimizations SHOULD be consistently without encapsulation, such optimizations MUST be consistently
enabled on all route reflectors. Otherwise, clients may receive an enabled on all route reflectors. Otherwise, clients may receive an
inconsistent view of the network, in turn leading to intra-domain inconsistent view of the network, in turn leading to intra-domain
forwarding loops. forwarding loops.
As discussed in section 11 of [RFC4456], the IGP locations of BGP As discussed in section 11 of [RFC4456], the IGP locations of BGP
route reflectors is important and has routing implications. This route reflectors is important and has routing implications. This
equally applies to the choice of the IGP locations configured on equally applies to the choice of the IGP locations configured on
optimal route reflectors. If a backup location is provided, it is optimal route reflectors. If a backup location is provided, it is
used when the primary IGP location disappears from the IGP (i.e. used when the primary IGP location disappears from the IGP (i.e.
fails). Just like the failure of a RR [RFC4456], it may result in fails). Just like the failure of a RR [RFC4456], it may result in
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multiple route reflectors handle route selection for all of them. multiple route reflectors handle route selection for all of them.
The operator may alternatively deploy one or multiple route reflector The operator may alternatively deploy one or multiple route reflector
for each IGP location or create any design in between. This choice for each IGP location or create any design in between. This choice
may depend on operational model (centralized vs per region), may depend on operational model (centralized vs per region),
acceptable blast radius in case of failure, acceptable number of IBGP acceptable blast radius in case of failure, acceptable number of IBGP
sessions for the mesh between the route reflectors, performance and sessions for the mesh between the route reflectors, performance and
configuration granularity of the equipment. configuration granularity of the equipment.
With this approach, an ISP can effect a hot potato routing policy With this approach, an ISP can effect a hot potato routing policy
even if route reflection has been moved out of the forwarding plane, even if route reflection has been moved out of the forwarding plane,
and hop-by-hop switching has been replaced by end-to-end MPLS or IP and hop-by-hop forwarding has been replaced by end-to-end MPLS or IP
encapsulation. Compared with a deployment of ADD-PATH on all encapsulation. Compared with a deployment of ADD-PATH on all
routers, BGP ORR reduces the amount of state which needs to be pushed routers, BGP Optimal Route Reflection (ORR) reduces the amount of
to the edge of the network in order to perform hot potato routing. state which needs to be pushed to the edge of the network in order to
perform hot potato routing.
Modifying the IGP location of BGP ORR does not interfere with Modifying the IGP location of BGP ORR does not interfere with
policies enforced before IGP tie-breaking (step e) in the BGP policies enforced before IGP tie-breaking (step e) of [RFC4271]
Decision Process Route. section 9.1.2.2 in the BGP Decision Process.
Calculating routes for different IGP locations requires multiple SPF Calculating routes for different IGP locations requires multiple
calculations and multiple (subsets of) BGP Decision Processes, which Shortest Path First (SPF) calculations and multiple (subsets of) BGP
requires more computing resources. This document allows for Decision Processes, which requires more computing resources. This
different granularity such as one Decision Process per route document allows for different granularity such as one Decision
reflector, per set of clients or per client. A more fine-grained Process per route reflector, per set of clients or per client. A
granularity may translate into more optimal hot potato routing at the more fine-grained granularity may translate into more optimal hot
cost of more computing power. Selecting to configure an IGP location potato routing at the cost of more computing power. Selecting to
per client has the highest precision as each client can be associated configure an IGP location per client has the highest precision as
with their ideal (own) IGP location. However, doing so may have an each client can be associated with their ideal (own) IGP location.
impact on the performance (as explained above). Using an IGP However, doing so may have an impact on the performance (as explained
location per set of clients implies a loss of precision, but reduces above). Using an IGP location per set of clients implies a loss of
the impact on the performance of the route reflector. Similarly, if precision, but reduces the impact on the performance of the route
an IGP location is selected for the whole routing instance, the reflector. Similarly, if an IGP location is selected for the whole
lowest precision is achieved, but the performance impact is minimal routing instance, the lowest precision is achieved, but the
(both should be equal to the [RFC4456] ones). The ability to run performance impact is minimal. In the last mode of operation both
fine-grained computations depends on the platform/hardware deployed, precision as well as perfomance metrics are equal to same metrics
the number of clients, the number of BGP routes and the size of the when using route reflection as described in [RFC4456] without ORR
IGP topology. In essence, sizing considerations are similar to the extension. The ability to run fine-grained computations depends on
deployments of BGP Route Reflector. the platform/hardware deployed, the number of clients, the number of
BGP routes and the size of the IGP topology. In essence, sizing
considerations are similar to the deployments of BGP Route Reflector.
5. Security Considerations 5. Security Considerations
This extension provides a new metric value using additional This extension provides a new metric value using additional
information for computing routes for BGP router reflectors. While information for computing routes for BGP route reflectors. While any
any improperly used metric value could impact the resiliency of the improperly used metric value could impact the resiliency of the
network, this extension does not change the underlying security network, this extension does not change the underlying security
issues inherent in the existing IBGP per [RFC4456]. issues inherent in the existing IBGP per [RFC4456].
This document does not introduce requirements for any new protection This document does not introduce requirements for any new protection
measures. measures.
6. IANA Considerations 6. IANA Considerations
This document does not request any IANA allocations. This document does not request any IANA allocations.
7. Acknowledgments 7. Acknowledgments
Authors would like to thank Keyur Patel, Eric Rosen, Clarence Authors would like to thank Keyur Patel, Eric Rosen, Clarence
Filsfils, Uli Bornhauser, Russ White, Jakob Heitz, Mike Shand, Jon Filsfils, Uli Bornhauser, Russ White, Jakob Heitz, Mike Shand, Jon
Mitchell, John Scudder, Jeff Haas, Martin Djernaes, Daniele Mitchell, John Scudder, Jeff Haas, Martin Djernaes, Daniele
Ceccarelli, Kieran Milne, Job Snijders, Randy Bush, Alvaro Retana and Ceccarelli, Kieran Milne, Job Snijders, Randy Bush, Alvaro Retana,
Lars Eggert for their valuable input. Francesca Palombini, Benjamin Kaduk, Zaheduzzaman Sarker and Lars
Eggert for their valuable input.
8. Contributors 8. Contributors
Following persons substantially contributed to the current format of Following persons substantially contributed to the current format of
the document: the document:
Stephane Litkowski Stephane Litkowski
Cisco System Cisco System
slitkows.ietf@gmail.com slitkows.ietf@gmail.com
skipping to change at page 9, line 38 skipping to change at page 9, line 43
[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>.
[RFC4456] Bates, T., Chen, E., and R. Chandra, "BGP Route [RFC4456] Bates, T., Chen, E., and R. Chandra, "BGP Route
Reflection: An Alternative to Full Mesh Internal BGP Reflection: An Alternative to Full Mesh Internal BGP
(IBGP)", RFC 4456, DOI 10.17487/RFC4456, April 2006, (IBGP)", RFC 4456, DOI 10.17487/RFC4456, April 2006,
<https://www.rfc-editor.org/info/rfc4456>. <https://www.rfc-editor.org/info/rfc4456>.
[RFC7911] Walton, D., Retana, A., Chen, E., and J. Scudder,
"Advertisement of Multiple Paths in BGP", RFC 7911,
DOI 10.17487/RFC7911, July 2016,
<https://www.rfc-editor.org/info/rfc7911>.
[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>.
9.2. Informative References 9.2. Informative References
[ISO10589] [ISO10589]
International Organization for Standardization, International Organization for Standardization,
"Intermediate system to Intermediate system intra-domain "Intermediate system to Intermediate system intra-domain
routeing information exchange protocol for use in routeing information exchange protocol for use in
skipping to change at page 10, line 23 skipping to change at page 10, line 33
[RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF [RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008, for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008,
<https://www.rfc-editor.org/info/rfc5340>. <https://www.rfc-editor.org/info/rfc5340>.
[RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
S. Ray, "North-Bound Distribution of Link-State and S. Ray, "North-Bound Distribution of Link-State and
Traffic Engineering (TE) Information Using BGP", RFC 7752, Traffic Engineering (TE) Information Using BGP", RFC 7752,
DOI 10.17487/RFC7752, March 2016, DOI 10.17487/RFC7752, March 2016,
<https://www.rfc-editor.org/info/rfc7752>. <https://www.rfc-editor.org/info/rfc7752>.
[RFC7911] Walton, D., Retana, A., Chen, E., and J. Scudder, [RFC7947] Jasinska, E., Hilliard, N., Raszuk, R., and N. Bakker,
"Advertisement of Multiple Paths in BGP", RFC 7911, "Internet Exchange BGP Route Server", RFC 7947,
DOI 10.17487/RFC7911, July 2016, DOI 10.17487/RFC7947, September 2016,
<https://www.rfc-editor.org/info/rfc7911>. <https://www.rfc-editor.org/info/rfc7947>.
Authors' Addresses Authors' Addresses
Robert Raszuk (editor) Robert Raszuk (editor)
NTT Network Innovations NTT Network Innovations
Email: robert@raszuk.net Email: robert@raszuk.net
Bruno Decraene (editor) Bruno Decraene (editor)
Orange Orange
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