BGP Traffic Engineering Attribute
draft-ietf-softwire-bgp-te-attribute-04
The information below is for an old version of the document that is already published as an RFC.
| Document | Type | RFC Internet-Draft (softwire WG) | |
|---|---|---|---|
| Authors | Yakov Rekhter , Hamid H. Ould-Brahim , Don Fedyk | ||
| Last updated | 2018-12-20 (Latest revision 2008-12-22) | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Formats | plain text htmlized pdfized bibtex | ||
| Reviews | |||
| Stream | WG state | (None) | |
| Document shepherd | (None) | ||
| IESG | IESG state | RFC 5543 (Proposed Standard) | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | Mark Townsley | ||
| Send notices to | (None) |
draft-ietf-softwire-bgp-te-attribute-04
Network Working Group Hamid Ould-Brahim (Nortel Networks)
Internet Draft Don Fedyk (Nortel Networks)
Expiration Date: June 2009 Yakov Rekhter (Juniper Networks)
Intended Status: Proposed Standard
BGP Traffic Engineering Attribute
draft-ietf-softwire-bgp-te-attribute-04.txt
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Abstract
This document defines a new BGP attribute, Traffic Engineering
attribute, that enables BGP to carry Traffic Engineering information.
The scope and applicability of this attribute currently excludes its
use for non-VPN reachability information.
1. Specification of Requirements
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].
2. Introduction
In certain cases (e.g., L1VPN [RFC5195]) it may be useful to augment
VPN reachability information carried in BGP with the Traffic
Engineering information.
This document defines a new BGP attribute, Traffic Engineering
attribute, that enables BGP [RFC4271] to carry Traffic Engineering
information.
Section 4 of [RFC5195] describes one possible usage of this
attribute.
The scope and applicability of this attribute currently excludes its
use for non-VPN reachability information.
Procedures for modifying the Traffic Engineering attribute, when re-
advertising a route that carries such attribute are outside the scope
of this document.
3. Traffic Engineering Attribute
Traffic Engineering attribute is an optional non-transitive BGP
attribute.
The information carried in this attribute is identical to what is
carried in the Interface Switching Capability Descriptor, as
specified in [RFC4203], [RFC5307].
The attribute contains one or more of the following:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Switching Cap | Encoding | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max LSP Bandwidth at priority 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max LSP Bandwidth at priority 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max LSP Bandwidth at priority 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max LSP Bandwidth at priority 3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max LSP Bandwidth at priority 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max LSP Bandwidth at priority 5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max LSP Bandwidth at priority 6 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max LSP Bandwidth at priority 7 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Switching Capability-specific information |
| (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Switching Capability (Switching Cap) field contains one of the
values specified in Section 3.1.1 of [RFC3471].
The Encoding field contains one of the values specified in Section
3.1.1 of [RFC3471].
The Reserved field SHOULD be set to 0 on transmit and MUST be ignored
on receive.
Maximum LSP Bandwidth is encoded as a list of eight 4 octet fields in
the IEEE floating point format [IEEE], with priority 0 first and
priority 7 last. The units are bytes (not bits!) per second.
The content of the Switching Capability specific information field
depends on the value of the Switching Capability field.
When the Switching Capability field is PSC-1, PSC-2, PSC-3, or PSC-4,
the Switching Capability specific information field includes Minimum
LSP Bandwidth and Interface MTU.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Minimum LSP Bandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface MTU |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Minimum LSP Bandwidth is encoded in a 4 octet field in the IEEE
floating point format. The units are bytes (not bits!) per second.
The Interface MTU is encoded as a 2 octet integer.
When the Switching Capability field is L2SC, there is no Switching
Capability specific information field present.
When the Switching Capability field is TDM, the Switching Capability
specific information field includes Minimum LSP Bandwidth and an
indication of whether the interface supports Standard or Arbitrary
SONET/SDH.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Minimum LSP Bandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Indication |
+-+-+-+-+-+-+-+-+
The Minimum LSP Bandwidth is encoded in a 4 octet field in the IEEE
floating point format. The units are bytes (not bits!) per second.
The indication of whether the interface supports Standard or
Arbitrary SONET/SDH is encoded as 1 octet. The value of this octet
is 0 if the interface supports Standard SONET/SDH, and 1 if the
interface supports Arbitrary SONET/SDH.
When the Switching Capability field is LSC, there is no Switching
Capability specific information field present.
4. Implication on aggregation
Routes that carry the Traffic Engineering Attribute have additional
semantics that could affect traffic forwarding behavior. Therefore,
such routes SHALL NOT be aggregated unless they share identical
Traffic Engineering Attributes.
Constructing the Traffic Engineering Attribute when aggregating
routes with identical Traffic Engineering attributes follows the
procedure of [RFC4201].
5. Implication on scalability
The use of the Traffic Engineering Attribute does not increase the
number of routes, but may increase the number of BGP Update messages
required to distribute the routes depending on whether these routes
share the same BGP Traffic Engineering attribute or not (see below).
When the routes differ in other than the Traffic Engineering
Attribute (e.g., differ in the set of Route Targets, and/or
NEXT_HOP), use of Traffic Engineering Attribute has no impact on the
number of BGP Update messages required to carry the routes. There is
also no impact when routes share all other attribute information and
have an aggregated or identical Traffic Engineering Attribute. When
routes share all other attribute information and have different
Traffic Engineering Attributes, routes must be distributed in per-
route BGP Update messages rather than a single message.
6. IANA Considerations
This document defines a new BGP attribute. This attribute is optional
and non-transitive.
7. Security Considerations
This extension to BGP does not change the underlying security issues
currently inherent in BGP. BGP security considerations are discussed
in RFC 4271
8. Acknowledgements
The authors would like to thank John Scudder and Jeffrey Haas for
their review and comments.
9. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4201] Kompella, K., Rekhter, Y., Berger, L., "Link Bundling in
MPLS Traffic Engineering (TE)", RFC 4201, October 2005<P>
[RFC4271] Rekhter, Y., T. Li, Hares, S., "A Border Gateway Protocol 4
(BGP-4)", RFC4271, January 2006.
[RFC3471] Berger, L., "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Functional Description", RFC 3471, January 2003.
[IEEE] IEEE, "IEEE Standard for Binary Floating-Point Arithmetic",
Standard 754-1985, 1985 (ISBN 1-5593-7653-8).
10. Non-Normative References
[RFC4203] Kompella, K., Rekhter, Y., "OSPF Extensions in Support of
Generalized Multi-Protocol Label Switching (GMPLS)", RFC4203, October
2005
[RFC5307] Kompella, K., Rekhter, Y., "Intermediate System to
Intermediate System (IS-IS) Extensions in Support of Generalized
Multi-Protocol Label Switching (GMPLS)", RFC5307, October 2005
[RFC5195] Ould-Brahim, H., Fedyk, D., Rekhter, Y., "BGP-Based Auto-
Discovery for Layer-1 VPNs", RFC5195, June 2008
11. Author Information
Hamid Ould-Brahim
Nortel Networks
Email: hbrahim@nortel.com
Don Fedyk
Nortel Networks
Email: dwfedyk@nortel.com
Yakov Rekhter
Juniper Networks, Inc.
email: yakov@juniper.com