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draft-ietf-softwire-bgp-te-attribute-04.txt --> rfc5543.txt

Network Working Group Hamid H. Ould-Brahim (Nortel Networks)
Internet Draft Don
Request for Comments: 5543 Nortel Networks
Category: Standards Track D. Fedyk (Nortel Networks)
Expiration Date: June 2009 Yakov
Alcatel-Lucent
Y. Rekhter (Juniper Networks)
Intended Status: Proposed Standard
Juniper Networks
May 2009

BGP Traffic Engineering Attribute

draft-ietf-softwire-bgp-te-attribute-04.txt

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Abstract

This document defines a new BGP attribute, the 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

Ould-Brahim, et al. Standards Track [Page 1]

RFC 2119 [RFC2119].

2. 5543 BGP TE Attribute May 2009

1. Introduction

In certain cases (e.g., L1VPN [RFC5195]) Layer-1 VPNs (L1VPNs) [RFC5195]), it may be
useful to augment the VPN reachability information carried in BGP
with the Traffic Engineering information.

This document defines a new BGP attribute, the 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
re-advertising a route that carries such attribute an attribute, are outside
the scope of this document.

2. 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].

3. Traffic Engineering Attribute

The Traffic Engineering attribute is an optional 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], [RFC4203] and [RFC5307].

The attribute contains one or more of the following:

Ould-Brahim, et al. Standards Track [Page 2]

RFC 5543 BGP TE Attribute May 2009

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 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 (Label Switched Path) Bandwidth is encoded as a list of
eight 4 octet 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.

Ould-Brahim, et al. Standards Track [Page 3]

RFC 5543 BGP TE Attribute May 2009

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 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 2-octet integer.

When the Switching Capability field is L2SC, Layer-2 Switch Capable (L2SC),
there is no Switching Capability specific information field present.

When the Switching Capability field is TDM, Time-Division-Multiplex (TDM)
capable, the Switching Capability specific information field includes
Minimum LSP Bandwidth and an indication of whether the interface
supports Standard or Arbitrary
SONET/SDH. SONET/SDH (Synchronous Optical
Network / Synchronous Digital Hierarchy).

The

Minimum LSP Bandwidth is encoded in a 4 octet 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, Lambda Switch Capable (LSC),
there is no Switching Capability specific information field present.

4. Implication on aggregation Aggregation

Routes that carry the Traffic Engineering Attribute attribute have additional
semantics that could affect traffic forwarding traffic-forwarding behavior. Therefore,
such routes SHALL NOT be aggregated unless they share identical
Traffic Engineering Attributes. attributes.

Ould-Brahim, et al. Standards Track [Page 4]

RFC 5543 BGP TE Attribute May 2009

Constructing the Traffic Engineering Attribute attribute when aggregating
routes with identical Traffic Engineering attributes follows the
procedure of [RFC4201].

5. Implication on scalability Scalability

The use of the Traffic Engineering Attribute attribute does not increase the
number of routes, but may increase the number of BGP Update messages
required to distribute the routes routes, depending on whether or not these
routes share the same BGP Traffic Engineering attribute or not (see below).

When the routes differ in other than in the Traffic Engineering
Attribute
attribute (e.g., differ in the set of Route Targets, Targets and/or NEXT_HOP),
use of the Traffic Engineering Attribute 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. attribute. When
routes share all other attribute information and have different
Traffic Engineering Attributes, attributes, routes must be distributed in per-
route
per-route BGP Update messages messages, rather than in a single message.

6. IANA Considerations

This document defines a new BGP attribute. attribute, Traffic Engineering. 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 4271.

8. Acknowledgements

The authors would like to thank John Scudder and Jeffrey Haas for
their review and comments.

9. References

9.1. Normative References

[IEEE] IEEE, "IEEE Standard for Binary Floating-Point Arithmetic",
Standard 754-1985, 1985 (ISBN 1-5593-7653-8).

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.

Ould-Brahim, et al. Standards Track [Page 5]

RFC 5543 BGP TE Attribute May 2009

[RFC3471] Berger, L., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Functional Description", RFC
3471, January 2003.

[RFC4201] Kompella, K., Rekhter, Y., and L. Berger, L., "Link Bundling in
MPLS Traffic Engineering (TE)", RFC 4201, October 2005<P> 2005.

[RFC4271] Rekhter, Y., T. Ed., Li, T., Ed., and S. Hares, S., Ed., "A Border
Gateway Protocol 4 (BGP-4)", RFC4271, January 2006.

[RFC3471] Berger, L., "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Functional Description", RFC 3471, 4271, January 2003.

[IEEE] IEEE, "IEEE Standard for Binary Floating-Point Arithmetic",
Standard 754-1985, 1985 (ISBN 1-5593-7653-8).

10. Non-Normative 2006.

9.2. Informative References

[RFC4203] Kompella, K., Ed., and Y. Rekhter, Y., Ed., "OSPF Extensions in
Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC4203, RFC 4203, October
2005 2005.

[RFC5195] Ould-Brahim, H., Fedyk, D., and Y. Rekhter, "BGP-Based
Auto-Discovery for Layer-1 VPNs", RFC 5195, June 2008.

[RFC5307] Kompella, K., Ed., and Y. Rekhter, Y., "Intermediate System to
Intermediate System (IS-IS) Ed., "IS-IS Extensions
in Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC5307, RFC 5307, October 2005

[RFC5195] Ould-Brahim, H., Fedyk, D., Rekhter, Y., "BGP-Based Auto-
Discovery for Layer-1 VPNs", RFC5195, June 2008

11. Author Information 2008.

Authors' Addresses

Hamid Ould-Brahim
Nortel Networks
Email:
EMail: hbrahim@nortel.com

Don Fedyk
Nortel Networks
Email: dwfedyk@nortel.com
Alcatel-Lucent
EMail: donald.fedyk@alcatel-lucent.com
Phone: 978-467-5645

Yakov Rekhter
Juniper Networks, Inc.
email: yakov@juniper.com
EMail: yakov@juniper.net

Ould-Brahim, et al. Standards Track [Page 6]

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