Codepoint Registry for the Flags Field in the Resource Reservation Protocol-Traffic Engineering (RSVP-TE) Session Attribute Object
Creates a registry for flags in the RSVP-TE Session Attribute object.
Farrel, A., "Codepoint Registry for the Flags Field in the Resource Reservation Protocol-Traffic Engineering (RSVP-TE) Session Attribute Object", RFC 4859, DOI 10.17487/RFC4859, April 2007, <https://www.rfc-editor.org/info/rfc4859>.
@misc{rfc4859,
series = {Request for Comments},
number = 4859,
howpublished = {RFC 4859},
publisher = {RFC Editor},
doi = {10.17487/RFC4859},
url = {https://www.rfc-editor.org/info/rfc4859},
author = {A. Farrel},
title = {{Codepoint Registry for the Flags Field in the Resource Reservation Protocol-Traffic Engineering (RSVP-TE) Session Attribute Object}},
pagetotal = 5,
year = 2007,
month = apr,
} RFC text
Contents
Network Working Group A. Farrel
Request for Comments: 4859 Old Dog Consulting
Category: Informational April 2007
Codepoint Registry for the Flags Field in
the Resource Reservation Protocol-Traffic Engineering (RSVP-TE)
Session Attribute Object
Status of This Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright Notice
Copyright (C) The IETF Trust (2007).
Abstract
This document provides instructions to IANA for the creation of a new
codepoint registry for the flags field in the Session Attribute
object of the Resource Reservation Protocol Traffic Engineering
(RSVP-TE) signaling messages used in Multiprotocol Label Switching
(MPLS) and Generalized MPLS (GMPLS) signaling.
1. Introduction
The Resource Reservation Protocol (RSVP) [RFC2205] has been extended
as RSVP for Traffic Engineering (RSVP-TE) for use in Multiprotocol
Label Switching (MPLS) signaling [RFC3209] and Generalized MPLS
(GMPLS) [RFC3473].
[RFC3209] introduced a new signaling object, the Session Attribute
object, that is carried on the RSVP Path message. The Session
Attribute object contains an eight-bit field of flags.
The original specification of RSVP-TE assigned uses to three of these
bit flags. Subsequent MPLS and GMPLS RFCs have assigned further
flags.
There is a need for a codepoint registry to track the use of the bit
flags in this field, to ensure that bits are not assigned more than
once, and to define the procedures by which such bits may be
assigned.
This document lists the current bit usage and provides information
for IANA to create a new registry. This document does not define the
uses of specific bits -- definitive procedures for the use of the
bits can be found in the referenced RFCs.
2. Existing Usage
2.1. RFC 3209
[RFC3209] defines the use of three bits as follows:
0x01 Local protection desired
0x02 Label recording desired
0x04 SE Style desired
2.2. RFC 4090
[RFC4090] defines the use of two bits as follows:
0x08 Bandwidth protection desired
0x10 Node protection desired
2.3. RFC 4736
[RFC4736] defines the use of one bit as follows:
0x20 Path re-evaluation request
3. Security Considerations
This informational document exists purely to create an IANA registry.
Such registries help to protect the IETF process against denial-of-
service attacks.
Otherwise there are no security considerations for this document.
4. IANA Considerations
IANA has created a new codepoint registry as follows.
The new registry has been placed under the "RSVP-TE Parameters"
branch of the tree.
The new registry has been termed "Session Attribute Object Flags."
Flags from this registry may only be assigned by IETF consensus
[RFC2434].
The registry references the flags already defined as described in
Section 2 of this document.
5. Acknowledgements
Thanks to JP Vasseur, Bill Fenner, and Thomas Narten for reviewing
this document.
6. References
6.1. Normative References
[RFC2205] Braden, R., Ed., Zhang, L., Berson, S., Herzog, S. and S.
Jamin, "Resource ReSerVation Protocol (RSVP) -- Version
1, Functional Specification", RFC 2205, September 1997.
[RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 2434,
October 1998.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, December 2001.
[RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling - Resource ReserVation
Protocol-Traffic Engineering (RSVP-TE) Extensions", RFC
3473, January 2003.
6.2. Informative References
[RFC4090] Pan, P., Ed., Swallow, G., Ed., and A. Atlas, Ed., "Fast
Reroute Extensions to RSVP-TE for LSP Tunnels", RFC 4090,
May 2005.
[RFC4736] Vasseur, JP., Ed., Ikejiri, Y., and R. Zhang,
"Reoptimization of Multiprotocol Label Switching (MPLS)
Traffic Engineering (TE) Loosely Routed Label Switched
Path (LSP)", RFC 4736, November 2006.
Author's Address
Adrian Farrel
Old Dog Consulting
EMail: adrian@olddog.co.uk
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ISO Plain Language
On this page
§1The Session Attribute Flags
The RSVP-TE Session Attribute object, carried in an RSVP Path message, contains an eight-bit flags field. RFC 3209 assigned uses to three bits, and later MPLS and GMPLS RFCs assigned additional bits. RFC 4859 lists existing uses and creates a registry to avoid assigning a bit more than once.
The Session Attribute object has eight flag bits, with uses assigned in several documents. The registry records those assignments so a bit is not reused accidentally.
§4Existing Uses and New Assignments
The RFC records six existing flag values: 0x01 for local protection, 0x02 for label recording, 0x04 for SE Style, 0x08 for bandwidth protection, 0x10 for node protection, and 0x20 for a path re-evaluation request. These uses are defined by RFCs 3209, 4090, and 4736. New flags may only be assigned by IETF consensus.
The initial registry lists six flags and the RFC that defined each use. IETF consensus is required to assign another flag.
§3Security Considerations
RFC 4859 says the registry helps protect the IETF process against denial-of-service attacks. Apart from that point, it states that there are no security considerations for the document.
The RFC says the registry helps protect the IETF process. It identifies no other security considerations.