Internet DRAFT - draft-dong-idr-inter-as-te-link-distribution
draft-dong-idr-inter-as-te-link-distribution
Network Working Group J. Dong
Internet-Draft M. Chen
Intended status: Standards Track Huawei Technologies
Expires: January 1, 2015 June 30, 2014
BGP Extensions for Inter-AS Traffic Engineering (TE) Link Distribution
draft-dong-idr-inter-as-te-link-distribution-00
Abstract
Protocol extensions to Interial Gataway Protocols (IGPs) have been
specified for the flooding of Traffice Engineering (TE) information
of the Inter-Autonomous System (AS) links into the local AS (RFC 5392
and RFC 5316), in which some information of the inter-AS links needs
to be manually configured. This document proposes BGP extensions for
dynamic advertisement of TE information of Inter-AS links between
adjacent ASes. Such mechanism may also be used for the distribution
of Inter-AS TE link information to some external entities, such as
Path Computation Element (PCE).
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.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months
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time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 1, 2015.
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Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Carrying Inter-AS Link Information in BGP . . . . . . . . . . 3
3. Operational Considerations . . . . . . . . . . . . . . . . . 4
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.1. Normative References . . . . . . . . . . . . . . . . . . 5
6.2. Informaltive References . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
Protocol extensions to Interial Gataway Protocols (IGPs) have been
specified for the flooding of Traffic Engineering (TE) information of
the Inter-Autonomous System (AS) links in local AS [RFC5392]
[RFC5316]. With those IGP extension mechanisms, some of the TE
information of the inter-AS links, such as remote AS number and
remote AS Border Router (ASBR) IDs are manually configured on the
ASBRs of local AS. This requires additional human intervention and
may be error-prone. Besides, an ASBR of local AS needs to generate a
local link-state information for the inter-AS TE link, and also needs
to 'proxy' for the remote ASBR to generate an additional link-state
information, in order for the two-way check of the Inter-AS link
during the path calculation. This introduces additional processing
on the ASBR of local AS and the 'proxy' information may be not quite
accurate. As bandwidth and other TE information of the Inter-AS
links are useful for establishing TE Label Switched Paths (LSPs)
across multiple ASes, such information needs to be dynamically
exchanged between the peering ASes.
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This document specifies BGP extensions for dynamic advertisement of
Inter-AS TE link information between the adjacent ASes. This
mechanism may also be used for the distribution of Inter-AS TE link
information to some external entities, such as Path Computation
Element (PCE).
2. Carrying Inter-AS Link Information in BGP
The Inter-AS link information is advertised in BGP UPDATE messages
using the MP_REACH_NLRI and MP_UNREACH_NLRI attributes [RFC4760].
The Link-State NLRI defined in [I-D.ietf-idr-ls-distribution] is
extended to carry the Inter-AS link information.
A new Protocol-ID is defined in the Link-State NLRI:
o Protocol-ID = 7: Inter-AS, The NLRI information has been sourced
from an Inter-AS connection
And a new Sub-TLV is defined in the Node Descriptor Sub-TLVs:
Sub-TLV Code Point Description Length
TBD BGP Identifier 4
BGP Identifier is the 4-octet unsigned integer that indicates a BGP
speaker, as defined in [RFC4271] [RFC6286].
The format of the link NLRI with Protocol-ID 7 is shown in the figure
below:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+
| Protocol-ID=7 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Identifier |
| (64 bits) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Local Node Descriptors (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Remote Node Descriptors (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Link Descriptors (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1. Inter-AS Link NLRI
The "Local Node Descriptors" field MUST contain the "Autonomous
System" Sub-TLV defined in [I-D.ietf-idr-ls-distribution] to identify
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the local AS number, and the "BGP Identifer" Sub-TLV defined in this
document to identify the local ASBR.
The "Remote Node Descriptors" field MUST contain the "Autonomous
System" Sub-TLV defined in [I-D.ietf-idr-ls-distribution] to identify
the remote AS number, and the "BGP Identifer" Sub-TLV defined in this
document to identify the remote ASBR.
For IPv4 Inter-AS link, the "Link Descriptors" field MUST use "IPv4
interface address" Sub-TLV to specify the local IPv4 address, and use
"IPv4 neighbor address" Sub-TLV to specify the peering IPv4 address
on the remote ASBR. The local and peering addresses are the IPv4
addresses used for the specific EBGP session between the local and
remote ASBRs.
For IPv6 Inter-AS link, the "Link Descriptors" field MUST use "IPv6
interface address" Sub-TLV to specify the local IPv6 address, and use
"IPv6 neighbor address" Sub-TLV to specify the peering IPv6 address
on the remote ASBR. The local and peering addresses are the IPv6
addresses used for the specific EBGP session between the local and
remote ASBRs.
The TE characteristics of the Inter-AS link, such as bandwidth,
Shared Risk Link Group (SRLG), IPv4/IPv6 TE Router ID, etc., SHOULD
be carried in the Link attribute TLVs of the BGP-LS attribute as
specified in [I-D.ietf-idr-ls-distribution]. No further extension to
the BGP-LS attribute is defined in this document.
3. Operational Considerations
The advertisement of Inter-AS TE link information SHOULD be
constrained to only between the adjacent ASes connected by the Inter-
AS link. BGP speakers SHOULD NOT advertise the Inter-AS TE link
information received from the peering AS to any other ASes. The ASBR
receiving the Inter-AS TE link information SHOULD redistribute such
information into the IGP of the local AS, using mechanisms defined in
[RFC5392] and [RFC5316].
The Inter-AS TE link information may optionally be advertised to an
external entity, for example PCE. Such advertisement SHOULD be
performed under agreement and policy control of the involved
administrative domains.
4. IANA Considerations
IANA needs to assign one new Protocol-ID for "Inter-AS" from the BGP-
TE/LS registry of Protocol-IDs.
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IANA needs to assign one new Sub-TLV for "BGP Identifier" from the
"node anchor, link descriptor and link attribute TLVs" registry.
5. Security Considerations
Procedures and protocol extensions defined in this document do not
affect the BGP security model. See the Security Considerations
section of [RFC4271] for a discussion of BGP security. Also refer to
[RFC4272] and [RFC6952] for analysis of security issues for BGP.
6. References
6.1. Normative References
[I-D.ietf-idr-ls-distribution]
Gredler, H., Medved, J., Previdi, S., Farrel, A., and S.
Ray, "North-Bound Distribution of Link-State and TE
Information using BGP", draft-ietf-idr-ls-distribution-05
(work in progress), May 2014.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
Protocol 4 (BGP-4)", RFC 4271, January 2006.
[RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
"Multiprotocol Extensions for BGP-4", RFC 4760, January
2007.
[RFC6286] Chen, E. and J. Yuan, "Autonomous-System-Wide Unique BGP
Identifier for BGP-4", RFC 6286, June 2011.
6.2. Informaltive References
[RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis", RFC
4272, January 2006.
[RFC5316] Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in
Support of Inter-Autonomous System (AS) MPLS and GMPLS
Traffic Engineering", RFC 5316, December 2008.
[RFC5392] Chen, M., Zhang, R., and X. Duan, "OSPF Extensions in
Support of Inter-Autonomous System (AS) MPLS and GMPLS
Traffic Engineering", RFC 5392, January 2009.
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[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, May 2013.
Authors' Addresses
Jie Dong
Huawei Technologies
Huawei Campus, No. 156 Beiqing Rd.
Beijing 100095
China
Email: jie.dong@huawei.com
Mach(Guoyi) Chen
Huawei Technologies
Huawei Campus, No. 156 Beiqing Rd.
Beijing 100095
China
Email: mach.chen@huawei.com
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