Internet DRAFT - draft-dong-idr-enhanced-end-of-rib
draft-dong-idr-enhanced-end-of-rib
Network Working Group J. Dong
Internet-Draft Huawei Technologies
Intended status: Standards Track October 19, 2015
Expires: April 21, 2016
Enhanced End-of-RIB Marker for BGP
draft-dong-idr-enhanced-end-of-rib-00
Abstract
This document specifies an enhanced BGP End-of-RIB marker which can
facilitate fine granular BGP route convergence for various BGP based
network services. A new BGP capability to negotiate the usage of the
enhanced End-of-RIB marker is also specified.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on April 21, 2016.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Enhanced End-of-RIB Marker . . . . . . . . . . . . . . . . . 3
3. BGP Enhanced End-of-RIB Capability . . . . . . . . . . . . . 3
4. Usage of Enhanced End-of-RIB Marker . . . . . . . . . . . . . 3
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . 4
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
8.1. Normative References . . . . . . . . . . . . . . . . . . 4
8.2. Informative References . . . . . . . . . . . . . . . . . 5
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
BGP [RFC4271] has been extended for the advertisement of different
kinds of information for various network services, some of which may
involve the exchange and synchronization of hundreds of thousands of
BGP routes. The time of BGP convergence can impact the availability
of some critical services, or the service of some high priority
customers.
For example, for Layer-3 Virtual Private Network (L3VPN) [RFC4364]
service, there can be more than thousands of VPN customers. Ideally
the route convergence of VPN customers should be independent of each
other. However, with existing BGP mechanism, the convergence of all
the customers' VPN routes is treated as a whole, which is not optimal
and may slow down the route convergence of particular VPN customers.
BGP Graceful Restart (GR) [RFC4724] defines an End-of-RIB marker
which can be used to indicate to BGP peers the completion of route
update for specific address family. Such End-of-RIB marker is sent
to BGP peers only when all the routes of specific address family has
been advertised. Before this End-of-RIB is received from BGP peers,
there is no way to know whether the update for a particular VPN
customer has completed, consequently this would delay the route
selection and further processing for that customer. In other word,
BGP route selection for any VPN customer has to be suspended until
the End-of-RIB marker for the corresponding address family is
received from BGP peers.
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Besides, update of the RT membership information with BGP RT-
Constrain mechanism [RFC4684] may trigger the advertisement of a set
of BGP routes which contain particular Route Targets (RT). It would
be beneficial for BGP speakers to know when the consequent routing
update is completed.
This document specifies an enhanced BGP End-of-RIB marker which can
facilitate fine granular BGP route convergence in various BGP based
network services. A new BGP capability to negotiate the usage of the
enhanced End-of-RIB marker is also specified.
2. Enhanced End-of-RIB Marker
The Enhanced End-of-RIB marker is similar to the End-of-RIB marker as
defined in [RFC4724], which is an UPDATE message with no reachable
Network Layer Reachability Information (NLRI) and empty withdrawn
NLRI. In addition, the Enhanced End-of-RIB marker also contains a
set of BGP Path Attributes which are used to identify a particular
group of BGP routes for which the advertisement has completed.
The Enhanced End-of-RIB marker can be used to indicate the completion
of routing update for specific route groups. One typical example of
the group is routes of a specific VPN customer, which is identified
by the RTs of the VPN.
3. BGP Enhanced End-of-RIB Capability
A new BGP capability called 'Enhanced End-of-RIB' Capability is
defined. The Capability code for this capability is to be assigned.
The Capability length field is zero.
By advertising this capability to a peer, a BGP speaker conveys to
the peer that the speaker support advertising and receiving the
Enhanced End-of-RIB marker and the related procedures described in
this document. After capability negotiation, if both the peer
speaker and local speaker support this capability, the Enhanced End-
of-RIB can be used to facilitate fine granular route convergence.
4. Usage of Enhanced End-of-RIB Marker
As an enhancement to the existing End-of-RIB marker [RFC4724], the
advertisement of Enhanced End-of-RIB marker can be used for fine
granular route convergence of specific route groups within a specific
address family. One typical scenario is to use the Enhanced End-of-
RIB marker as the indication of routing update completion of specific
VPN customer. In such case, the Enhanced End-of-RIB marker SHOULD
carry the Extended Communities attribute which contains the RTs of
the VPN. There are also other use cases of fine granular BGP route
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convergence, which is for further study and not included in current
version of this document.
The Enhanced End-of-RIB marker may be used only for a subset of VPN
customers which require faster route convergence, selection of such
VPN customers is based on the operator's policy. When the route
advertisement for such VPN customers is completed, the sending BGP
speaker MUST send the Enhanced End-of-RIB marker with RTs identifying
the VPN customers to the peer. The receiving BGP speaker SHOULD use
the Enhanced End-of-RIB marker as the trigger of route selection and
further processing of routes of the identified VPN customers.
The Enhanced End-of-RIB can be used for both the initial routing
update and the routing updates triggered by the update of RT
membership information [RFC4684], while the traditional End-of-RIB
marker SHOULD still be used to indicate the completion of routing
updates for the whole address family.
5. IANA Considerations
A new BGP capability - Enhanced End-of-RIB Capability is defined in
this document. The Capability code needs to be assigned by the IANA.
6. Security Considerations
Procedures and protocol extensions defined in this document do not
affect the BGP security model. See [RFC6952] for details.
7. Acknowledgements
TBD
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
<http://www.rfc-editor.org/info/rfc4271>.
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[RFC4724] Sangli, S., Chen, E., Fernando, R., Scudder, J., and Y.
Rekhter, "Graceful Restart Mechanism for BGP", RFC 4724,
DOI 10.17487/RFC4724, January 2007,
<http://www.rfc-editor.org/info/rfc4724>.
8.2. Informative References
[RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
2006, <http://www.rfc-editor.org/info/rfc4364>.
[RFC4684] Marques, P., Bonica, R., Fang, L., Martini, L., Raszuk,
R., Patel, K., and J. Guichard, "Constrained Route
Distribution for Border Gateway Protocol/MultiProtocol
Label Switching (BGP/MPLS) Internet Protocol (IP) Virtual
Private Networks (VPNs)", RFC 4684, DOI 10.17487/RFC4684,
November 2006, <http://www.rfc-editor.org/info/rfc4684>.
[RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of
BGP, LDP, PCEP, and MSDP Issues According to the Keying
and Authentication for Routing Protocols (KARP) Design
Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013,
<http://www.rfc-editor.org/info/rfc6952>.
Author's Address
Jie Dong
Huawei Technologies
Huawei Campus, No.156 Beiqing Rd.
Beijing 100095
China
Email: jie.dong@huawei.com
Dong Expires April 21, 2016 [Page 5]
