draft-ietf-idr-rfc2796bis-02.txt   rfc4456.txt 
Network Working Group T. Bates (Cisco Systems) Network Working Group T. Bates
Internet Draft R. Chandra (Sonoa Systems) Request for Comments: 4456 E. Chen
Expiration Date: April 2006 E. Chen (Cisco Systems) Obsoletes: 2796, 1966 Cisco Systems
Category: Standards Track R. Chandra
BGP Route Reflection - Sonoa Systems
An Alternative to Full Mesh IBGP April 2006
draft-ietf-idr-rfc2796bis-02.txt
Status of this Memo
By submitting this Internet-Draft, each author represents that any BGP Route Reflection:
applicable patent or other IPR claims of which he or she is aware An Alternative to Full Mesh Internal BGP (IBGP)
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Status of This Memo
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Drafts.
Internet-Drafts are draft documents valid for a maximum of six months This document specifies an Internet standards track protocol for the
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time. It is inappropriate to use Internet-Drafts as reference improvements. Please refer to the current edition of the "Internet
material or to cite them other than as "work in progress." Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
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Abstract Abstract
The Border Gateway Protocol (BGP) is an inter-autonomous system The Border Gateway Protocol (BGP) is an inter-autonomous system
routing protocol designed for TCP/IP internets. Typically all BGP routing protocol designed for TCP/IP internets. Typically, all BGP
speakers within a single AS must be fully meshed so that any external speakers within a single AS must be fully meshed so that any external
routing information must be re-distributed to all other routers routing information must be re-distributed to all other routers
within that AS. This represents a serious scaling problem that has within that Autonomous System (AS). This represents a serious
been well documented with several alternatives proposed. scaling problem that has been well documented with several
alternatives proposed.
This document describes the use and design of a method known as This document describes the use and design of a method known as
"Route Reflection" to alleviate the the need for "full mesh" IBGP. "route reflection" to alleviate the need for "full mesh" Internal BGP
(IBGP).
This documents obsoletes RFC 2796 and RFC 1966. This document obsoletes RFC 2796 and RFC 1966.
Table of Contents
1. Introduction ....................................................2
2. Specification of Requirements ...................................2
3. Design Criteria .................................................3
4. Route Reflection ................................................3
5. Terminology and Concepts ........................................4
6. Operation .......................................................5
7. Redundant RRs ...................................................6
8. Avoiding Routing Information Loops ..............................6
9. Impact on Route Selection .......................................7
10. Implementation Considerations ..................................7
11. Configuration and Deployment Considerations ....................7
12. Security Considerations ........................................8
13. Acknowledgements ...............................................9
14. References .....................................................9
14.1. Normative References ......................................9
14.2. Informative References ....................................9
Appendix A: Comparison with RFC 2796 ..............................10
Appendix B: Comparison with RFC 1966 ..............................10
1. Introduction 1. Introduction
Typically all BGP speakers within a single AS must be fully meshed Typically, all BGP speakers within a single AS must be fully meshed
and any external routing information must be re-distributed to all and any external routing information must be re-distributed to all
other routers within that AS. For n BGP speakers within an AS that other routers within that AS. For n BGP speakers within an AS that
requires to maintain n*(n-1)/2 unique IBGP sessions. This "full requires to maintain n*(n-1)/2 unique Internal BGP (IBGP) sessions.
mesh" requirement clearly does not scale when there are a large This "full mesh" requirement clearly does not scale when there are a
number of IBGP speakers each exchanging a large volume of routing large number of IBGP speakers each exchanging a large volume of
information, as is common in many of today's networks. routing information, as is common in many of today's networks.
This scaling problem has been well documented and a number of This scaling problem has been well documented, and a number of
proposals have been made to alleviate this [2,3]. This document proposals have been made to alleviate this [2,3]. This document
represents another alternative in alleviating the need for a "full represents another alternative in alleviating the need for a "full
mesh" and is known as "Route Reflection". This approach allows a BGP mesh" and is known as "route reflection". This approach allows a BGP
speaker (known as "Route Reflector") to advertise IBGP learned routes speaker (known as a "route reflector") to advertise IBGP learned
to certain IBGP peers. It represents a change in the commonly routes to certain IBGP peers. It represents a change in the commonly
understood concept of IBGP, and the addition of two new optional non- understood concept of IBGP, and the addition of two new optional
transitive BGP attributes to prevent loops in routing updates. non-transitive BGP attributes to prevent loops in routing updates.
This documents obsoletes RFC 2796 [6] and RFC 1966 [4]. This document obsoletes RFC 2796 [6] and RFC 1966 [4].
2. Specification of Requirements 2. Specification of Requirements
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", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [7]. document are to be interpreted as described in RFC 2119 [7].
3. Design Criteria 3. Design Criteria
Route Reflection was designed to satisfy the following criteria. Route reflection was designed to satisfy the following criteria.
o Simplicity o Simplicity
Any alternative must be both simple to configure as well as Any alternative must be simple to configure and easy to
understand. understand.
o Easy Transition o Easy Transition
It must be possible to transition from a full mesh It must be possible to transition from a full-mesh
configuration without the need to change either topology or AS. configuration without the need to change either topology or AS.
This is an unfortunate management overhead of the technique This is an unfortunate management overhead of the technique
proposed in [3]. proposed in [3].
o Compatibility o Compatibility
It must be possible for non compliant IBGP peers to continue be It must be possible for noncompliant IBGP peers to continue to
part of the original AS or domain without any loss of BGP be part of the original AS or domain without any loss of BGP
routing information. routing information.
These criteria were motivated by operational experiences of a very These criteria were motivated by operational experiences of a very
large and topology rich network with many external connections. large and topology-rich network with many external connections.
4. Route Reflection 4. Route Reflection
The basic idea of Route Reflection is very simple. Let us consider The basic idea of route reflection is very simple. Let us consider
the simple example depicted in Figure 1 below. the simple example depicted in Figure 1 below.
+-------+ +-------+ +-------+ +-------+
| | IBGP | | | | IBGP | |
| RTR-A |--------| RTR-B | | RTR-A |--------| RTR-B |
| | | | | | | |
+-------+ +-------+ +-------+ +-------+
\ / \ /
IBGP \ ASX / IBGP IBGP \ ASX / IBGP
\ / \ /
+-------+ +-------+
| | | |
| RTR-C | | RTR-C |
| | | |
+-------+ +-------+
Figure 1: Full Mesh IBGP Figure 1: Full-Mesh IBGP
In ASX there are three IBGP speakers (routers RTR-A, RTR-B and RTR- In ASX, there are three IBGP speakers (routers RTR-A, RTR-B, and
C). With the existing BGP model, if RTR-A receives an external route RTR-C). With the existing BGP model, if RTR-A receives an external
and it is selected as the best path it must advertise the external route and it is selected as the best path it must advertise the
route to both RTR-B and RTR-C. RTR-B and RTR-C (as IBGP speakers) external route to both RTR-B and RTR-C. RTR-B and RTR-C (as IBGP
will not re-advertise these IBGP learned routes to other IBGP speakers) will not re-advertise these IBGP learned routes to other
speakers. IBGP speakers.
If this rule is relaxed and RTR-C is allowed to advertise IBGP If this rule is relaxed and RTR-C is allowed to advertise IBGP
learned routes to IBGP peers, then it could re-advertise (or reflect) learned routes to IBGP peers, then it could re-advertise (or reflect)
the IBGP routes learned from RTR-A to RTR-B and vice versa. This the IBGP routes learned from RTR-A to RTR-B and vice versa. This
would eliminate the need for the IBGP session between RTR-A and RTR-B would eliminate the need for the IBGP session between RTR-A and RTR-B
as shown in Figure 2 below. as shown in Figure 2 below.
+-------+ +-------+ +-------+ +-------+
| | | | | | | |
| RTR-A | | RTR-B | | RTR-A | | RTR-B |
skipping to change at page 4, line 21 skipping to change at page 4, line 31
IBGP \ ASX / IBGP IBGP \ ASX / IBGP
\ / \ /
+-------+ +-------+
| | | |
| RTR-C | | RTR-C |
| | | |
+-------+ +-------+
Figure 2: Route Reflection IBGP Figure 2: Route Reflection IBGP
The Route Reflection scheme is based upon this basic principle. The route reflection scheme is based upon this basic principle.
5. Terminology and Concepts 5. Terminology and Concepts
We use the term "Route Reflection" to describe the operation of a BGP We use the term "route reflection" to describe the operation of a BGP
speaker advertising an IBGP learned route to another IBGP peer. Such speaker advertising an IBGP learned route to another IBGP peer. Such
a BGP speaker is said to be a "Route Reflector" (RR), and such a a BGP speaker is said to be a "route reflector" (RR), and such a
route is said to be a reflected route. route is said to be a reflected route.
The internal peers of a RR are divided into two groups: The internal peers of an RR are divided into two groups:
1) Client Peers 1) Client peers
2) Non-Client Peers 2) Non-Client peers
A RR reflects routes between these groups, and may reflect routes An RR reflects routes between these groups, and may reflect routes
among client peers. A RR along with its client peers form a Cluster. among client peers. An RR along with its client peers form a
The Non-Client peer must be fully meshed but the Client peers need cluster. The Non-Client peer must be fully meshed but the Client
not be fully meshed. Figure 3 depicts a simple example outlining the peers need not be fully meshed. Figure 3 depicts a simple example
basic RR components using the terminology noted above. outlining the basic RR components using the terminology noted above.
/ - - - - - - - - - - - - - - / - - - - - - - - - - - - - -
| Cluster | | Cluster |
+-------+ +-------+ +-------+ +-------+
| | | | | | | | | | | |
| RTR-A | | RTR-B | | RTR-A | | RTR-B |
| |Client | |Client | | | |Client | |Client | |
+-------+ +-------+ +-------+ +-------+
| \ / | | \ / |
IBGP \ / IBGP IBGP \ / IBGP
skipping to change at page 5, line 33 skipping to change at page 5, line 33
+-------+ +-------+ +-------+ +-------+
| RTR-D | IBGP | RTR-E | | RTR-D | IBGP | RTR-E |
| Non- |---------| Non- | | Non- |---------| Non- |
|Client | |Client | |Client | |Client |
+-------+ +-------+ +-------+ +-------+
Figure 3: RR Components Figure 3: RR Components
6. Operation 6. Operation
When a RR receives a route from an IBGP peer, it selects the best When an RR receives a route from an IBGP peer, it selects the best
path based on its path selection rule. After the best path is path based on its path selection rule. After the best path is
selected, it must do the following depending on the type of the peer selected, it must do the following depending on the type of peer it
it is receiving the best path from: is receiving the best path from
1) A Route from a Non-Client IBGP peer 1) A route from a Non-Client IBGP peer:
Reflect to all the Clients. Reflect to all the Clients.
2) A Route from a Client peer 2) A route from a Client peer:
Reflect to all the Non-Client peers and also to the Client Reflect to all the Non-Client peers and also to the Client
peers. (Hence the Client peers are not required to be fully peers. (Hence the Client peers are not required to be fully
meshed.) meshed.)
An Autonomous System could have many RRs. A RR treats other RRs just An Autonomous System could have many RRs. An RR treats other RRs
like any other internal BGP speakers. A RR could be configured to just like any other internal BGP speakers. An RR could be configured
have other RRs in a Client group or Non-client group. to have other RRs in a Client group or Non-client group.
In a simple configuration the backbone could be divided into many In a simple configuration, the backbone could be divided into many
clusters. Each RR would be configured with other RRs as Non-Client clusters. Each RR would be configured with other RRs as Non-Client
peers (thus all the RRs will be fully meshed.). The Clients will be peers (thus all the RRs will be fully meshed). The Clients will be
configured to maintain IBGP session only with the RR in their configured to maintain IBGP session only with the RR in their
cluster. Due to route reflection, all the IBGP speakers will receive cluster. Due to route reflection, all the IBGP speakers will receive
reflected routing information. reflected routing information.
It is possible in a Autonomous System to have BGP speakers that do It is possible in an Autonomous System to have BGP speakers that do
not understand the concept of Route-Reflectors (let us call them not understand the concept of route reflectors (let us call them
conventional BGP speakers). The Route-Reflector Scheme allows such conventional BGP speakers). The route reflector scheme allows such
conventional BGP speakers to co-exist. Conventional BGP speakers conventional BGP speakers to coexist. Conventional BGP speakers
could be either members of a Non-Client group or a Client group. This could be members of either a Non-Client group or a Client group.
allows for an easy and gradual migration from the current IBGP model This allows for an easy and gradual migration from the current IBGP
to the Route Reflection model. One could start creating clusters by model to the route reflection model. One could start creating
configuring a single router as the designated RR and configuring clusters by configuring a single router as the designated RR and
other RRs and their clients as normal IBGP peers. Additional clusters configuring other RRs and their clients as normal IBGP peers.
can be created gradually. Additional clusters can be created gradually.
7. Redundant RRs 7. Redundant RRs
Usually a cluster of clients will have a single RR. In that case, the Usually, a cluster of clients will have a single RR. In that case,
cluster will be identified by the BGP Identifier of the RR. However, the cluster will be identified by the BGP Identifier of the RR.
this represents a single point of failure so to make it possible to However, this represents a single point of failure so to make it
have multiple RRs in the same cluster, all RRs in the same cluster possible to have multiple RRs in the same cluster, all RRs in the
can be configured with a 4-byte CLUSTER_ID so that an RR can discard same cluster can be configured with a 4-byte CLUSTER_ID so that an RR
routes from other RRs in the same cluster. can discard routes from other RRs in the same cluster.
8. Avoiding Routing Information Loops 8. Avoiding Routing Information Loops
When a route is reflected, it is possible through mis-configuration When a route is reflected, it is possible through misconfiguration to
to form route re-distribution loops. The Route Reflection method form route re-distribution loops. The route reflection method
defines the following attributes to detect and avoid routing defines the following attributes to detect and avoid routing
information loops: information loops:
ORIGINATOR_ID ORIGINATOR_ID
ORIGINATOR_ID is a new optional, non-transitive BGP attribute of Type ORIGINATOR_ID is a new optional, non-transitive BGP attribute of Type
code 9. This attribute is 4 bytes long and it will be created by a RR code 9. This attribute is 4 bytes long and it will be created by an
in reflecting a route. This attribute will carry the BGP Identifier RR in reflecting a route. This attribute will carry the BGP
of the originator of the route in the local AS. A BGP speaker SHOULD Identifier of the originator of the route in the local AS. A BGP
NOT create an ORIGINATOR_ID attribute if one already exists. A speaker SHOULD NOT create an ORIGINATOR_ID attribute if one already
router which recognizes the ORIGINATOR_ID attribute SHOULD ignore a exists. A router that recognizes the ORIGINATOR_ID attribute SHOULD
route received with its BGP Identifier as the ORIGINATOR_ID. ignore a route received with its BGP Identifier as the ORIGINATOR_ID.
CLUSTER_LIST CLUSTER_LIST
CLUSTER_LIST is a new optional, non-transitive BGP attribute of Type
CLUSTER_LIST is a new, optional, non-transitive BGP attribute of Type
code 10. It is a sequence of CLUSTER_ID values representing the code 10. It is a sequence of CLUSTER_ID values representing the
reflection path that the route has passed. reflection path that the route has passed.
When a RR reflects a route, it MUST prepend the local CLUSTER_ID to When an RR reflects a route, it MUST prepend the local CLUSTER_ID to
the CLUSTER_LIST. If the CLUSTER_LIST is empty, it MUST create a new the CLUSTER_LIST. If the CLUSTER_LIST is empty, it MUST create a new
one. Using this attribute an RR can identify if the routing one. Using this attribute an RR can identify if the routing
information has looped back to the same cluster due to mis- information has looped back to the same cluster due to
configuration. If the local CLUSTER_ID is found in the CLUSTER_LIST, misconfiguration. If the local CLUSTER_ID is found in the
the advertisement received SHOULD be ignored. CLUSTER_LIST, the advertisement received SHOULD be ignored.
9. Impact on Route Selection 9. Impact on Route Selection
The BGP Decision Process Tie Breaking rules (Sect. 9.1.2.2, [1]) are The BGP Decision Process Tie Breaking rules (Sect. 9.1.2.2, [1]) are
modified as follows: modified as follows:
If a route carries the ORIGINATOR_ID attribute, then in Step f) If a route carries the ORIGINATOR_ID attribute, then in Step f)
the ORIGINATOR_ID SHOULD be treated as the BGP Identifier of the ORIGINATOR_ID SHOULD be treated as the BGP Identifier of the
the BGP speaker that has advertised the route. BGP speaker that has advertised the route.
In addition, the following rule SHOULD be inserted between Steps In addition, the following rule SHOULD be inserted between Steps
f) and g): a BGP Speaker SHOULD prefer a route with the shorter f) and g): a BGP Speaker SHOULD prefer a route with the shorter
CLUSTER_LIST length. The CLUSTER_LIST length is zero if a route CLUSTER_LIST length. The CLUSTER_LIST length is zero if a route
does not carry the CLUSTER_LIST attribute. does not carry the CLUSTER_LIST attribute.
10. Implementation Considerations 10. Implementation Considerations
Care should be taken to make sure that none of the BGP path Care should be taken to make sure that none of the BGP path
attributes defined above can be modified through configuration when attributes defined above can be modified through configuration when
exchanging internal routing information between RRs and Clients and exchanging internal routing information between RRs and Clients and
Non-Clients. Their modification could potentially result in routing Non-Clients. Their modification could potentially result in routing
loops. loops.
In addition, when a RR reflects a route, it SHOULD NOT modify the In addition, when a RR reflects a route, it SHOULD NOT modify the
following path attributes: NEXT_HOP, AS_PATH, LOCAL_PREF, and MED. following path attributes: NEXT_HOP, AS_PATH, LOCAL_PREF, and MED.
Their modification could potential result in routing loops. Their modification could potentially result in routing loops.
11. Configuration and Deployment Considerations 11. Configuration and Deployment Considerations
The BGP protocol provides no way for a Client to identify itself The BGP protocol provides no way for a Client to identify itself
dynamically as a Client of an RR. The simplest way to achieve this dynamically as a Client of an RR. The simplest way to achieve this
is by manual configuration. is by manual configuration.
One of the key component of the route reflection approach in One of the key component of the route reflection approach in
addressing the scaling issue is that the RR summarizes routing addressing the scaling issue is that the RR summarizes routing
information and only reflects its best path. information and only reflects its best path.
Both MEDs and IGP metrics may impact the BGP route selection. Both Multi-Exit Discriminators (MEDs) and Interior Gateway Protocol
Because MEDs are not always comparable and the IGP metric may differ (IGP) metrics may impact the BGP route selection. Because MEDs are
for each router, with certain route reflection topologies the route not always comparable and the IGP metric may differ for each router,
reflection approach may not yield the same route selection result as with certain route reflection topologies the route reflection
that of the full IBGP mesh approach. A way to make route selection approach may not yield the same route selection result as that of the
the same as it would be with the full IBGP mesh approach is to make full IBGP mesh approach. A way to make route selection the same as
sure that route reflectors are never forced to perform the BGP route it would be with the full IBGP mesh approach is to make sure that
selection based on IGP metrics which are significantly different from route reflectors are never forced to perform the BGP route selection
the IGP metrics of their clients, or based on incomparable MEDs. The based on IGP metrics that are significantly different from the IGP
former can be achieved by configuring the intra-cluster IGP metrics metrics of their clients, or based on incomparable MEDs. The former
to be better than the inter-cluster IGP metrics, and maintaining full can be achieved by configuring the intra-cluster IGP metrics to be
mesh within the cluster. The latter can be achieved by: better than the inter-cluster IGP metrics, and maintaining full mesh
within the cluster. The latter can be achieved by
o setting the local preference of a route at the border router to o setting the local preference of a route at the border router to
reflect the MED values. reflect the MED values, or
o or by making sure the AS-path lengths from different ASs are o making sure the AS-path lengths from different ASes are
different when the AS-path length is used as a route selection different when the AS-path length is used as a route selection
criteria. criteria, or
o or by configuring community based policies using which the o configuring community-based policies to influence the route
reflector can decide on the best route. selection.
One could argue though that the latter requirement is overly One could argue though that the latter requirement is overly
restrictive, and perhaps impractical in some cases. One could restrictive, and perhaps impractical in some cases. One could
further argue that as long as there are no routing loops, there are further argue that as long as there are no routing loops, there are
no compelling reasons to force route selection with route reflectors no compelling reasons to force route selection with route reflectors
to be the same as it would be with the full IBGP mesh approach. to be the same as it would be with the full IBGP mesh approach.
To prevent routing loops and maintain consistent routing view, it is To prevent routing loops and maintain consistent routing view, it is
essential that the network topology be carefully considered in essential that the network topology be carefully considered in
designing a route reflection topology. In general, the route designing a route reflection topology. In general, the route
reflection topology should congruent with the network topology when reflection topology should be congruent with the network topology
there exist multiple paths for a prefix. One commonly used approach when there exist multiple paths for a prefix. One commonly used
is the POP-based reflection, in which each POP maintains its own approach is the reflection based on Point of Presence (POP), in which
route reflectors serving clients in the POP, and all route reflectors each POP maintains its own route reflectors serving clients in the
are fully meshed. In addition, clients of the reflectors in each POP POP, and all route reflectors are fully meshed. In addition, clients
are often fully meshed for the purpose of optimal intra-POP routing, of the reflectors in each POP are often fully meshed for the purpose
and the intra-POP IGP metrics are configured to be better than the of optimal intra-POP routing, and the intra-POP IGP metrics are
inter-POP IGP metrics. configured to be better than the inter-POP IGP metrics.
12. Security Considerations 12. Security Considerations
This extension to BGP does not change the underlying security issues This extension to BGP does not change the underlying security issues
inherent in the existing IBGP [1, 5]. inherent in the existing IBGP [1, 5].
13. Acknowledgments 13. Acknowledgements
The authors would like to thank Dennis Ferguson, John Scudder, Paul The authors would like to thank Dennis Ferguson, John Scudder, Paul
Traina and Tony Li for the many discussions resulting in this work. Traina, and Tony Li for the many discussions resulting in this work.
This idea was developed from an earlier discussion between Tony Li This idea was developed from an earlier discussion between Tony Li
and Dimitri Haskin. and Dimitri Haskin.
In addition, the authors would like to acknowledge valuable review In addition, the authors would like to acknowledge valuable review
and suggestions from Yakov Rekhter on this document, and helpful and suggestions from Yakov Rekhter on this document, and helpful
comments from Tony Li, Rohit Dube, John Scudder and Bruce Cole. comments from Tony Li, Rohit Dube, John Scudder, and Bruce Cole.
14. References 14. References
14.1. Normative References 14.1. Normative References
[1] Rekhter, Y., T. Li and S. Hares, "A Border Gateway Protocol 4 [1] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway Protocol 4
(BGP-4)", draft-ietf-idr-bgp4-26.txt, October 2004. (BGP-4)", RFC 4271, January 2006.
14.2. Informative References 14.2. Informative References
[2] Haskin, D., "A BGP/IDRP Route Server alternative to a full mesh [2] Savola, P., "Reclassification of RFC 1863 to Historic", RFC
routing", RFC 1863, October 1995. 4223, October 2005.
[3] Traina, P., "Limited Autonomous System Confederations for BGP", [3] Traina, P., McPherson, D., and J. Scudder, "Autonomous System
RFC 1965, June 1996. Confederations for BGP", RFC 3065, February 2001.
[4] Bates, T. and R. Chandra, "BGP Route Reflection An alternative [4] Bates, T. and R. Chandra, "BGP Route Reflection An alternative
to full mesh IBGP", RFC 1966, June 1996. to full mesh IBGP", RFC 1966, June 1996.
[5] Heffernan, A., "Protection of BGP Sessions via the TCP MD5 [5] Heffernan, A., "Protection of BGP Sessions via the TCP MD5
Signature Option", RFC 2385, August 1998. Signature Option", RFC 2385, August 1998.
[6] Bates, T., R. Chandra and E. Chen "BGP Route Reflection - An [6] Bates, T., Chandra, R., and E. Chen, "BGP Route Reflection - An
Alternative to Full Mesh IBGP", RFC 2796, Arpil 2000. Alternative to Full Mesh IBGP", RFC 2796, April 2000.
[7] Bradner, S., "Key words for use in RFCs to Indicate Requirement [7] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997. Levels", BCP 14, RFC 2119, March 1997.
15. Authors' Addresses Appendix A: Comparison with RFC 2796
The impact on route selection is added.
The pictorial description of the encoding of the CLUSTER_LIST
attribute is removed as the description is redundant to the BGP
specification, and the attribute length field is inadvertently
described as one octet.
Appendix B: Comparison with RFC 1966
All the changes listed in Appendix A, plus the following.
Several terminologies related to route reflection are clarified, and
the reference to EBGP routes/peers are removed.
The handling of a routing information loop (due to route reflection)
by a receiver is clarified and made more consistent.
The addition of a CLUSTER_ID to the CLUSTER_LIST has been changed
from "append" to "prepend" to reflect the deployed code.
The section on "Configuration and Deployment Considerations" has been
expanded to address several operational issues.
Authors' Addresses
Tony Bates Tony Bates
Cisco Systems, Inc. Cisco Systems, Inc.
170 West Tasman Drive 170 West Tasman Drive
San Jose, CA 95134 San Jose, CA 95134
EMail: tbates@cisco.com EMail: tbates@cisco.com
Ravi Chandra Ravi Chandra
Sonoa Systems, Inc. Sonoa Systems, Inc.
3255-7 Scott Blvd. 3255-7 Scott Blvd.
Santa Clara, CA 95054 Santa Clara, CA 95054
Email: rchandra@sonoasystems.com EMail: rchandra@sonoasystems.com
Enke Chen Enke Chen
Cisco Systems, Inc. Cisco Systems, Inc.
170 West Tasman Drive 170 West Tasman Drive
San Jose, CA 95134 San Jose, CA 95134
EMail: enkechen@cisco.com EMail: enkechen@cisco.com
16. Appendix A Comparison with RFC 2796 Full Copyright Statement
The impact on route selection is added.
The pictorial description of the encoding of the CLUSTER_LIST
attribute is removed as the description is redundant to the BGP
specification, and the attribute length field is inadvertently
described as one octet.
17. Appendix B Comparison with RFC 1966
All the changes listed in Appendix A, plus the following.
Several terminologies related to route reflection are clarified, and
the reference to EBGP routes/peers are removed.
The handling of a routing information loop (due to route reflection) Copyright (C) The Internet Society (2006).
by a receiver is clarified and made more consistent.
The addition of a CLUSTER_ID to the CLUSTER_LIST has been changed This document is subject to the rights, licenses and restrictions
from "append" to "prepend" to reflect the deployed code. contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
The section on "Configuration and Deployment Considerations" has been This document and the information contained herein are provided on an
expanded to address several operational issues. "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
18. Intellectual Property Considerations Intellectual Property
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
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found in BCP 78 and BCP 79. found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any Copies of IPR disclosures made to the IETF Secretariat and any
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The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
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19. Full Copyright Notice
Copyright (C) The Internet Society (2005).
This document is subject to the rights, licenses and restrictions Acknowledgement
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an Funding for the RFC Editor function is provided by the IETF
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS Administrative Support Activity (IASA).
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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