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 (C) The IETF Trust (2007).
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.
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
[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
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
Farrel Informational [Page 1]RFC 4859 Registry for RSVP-TE Session Flags April 2007
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 Usage2.1. 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-
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."
Farrel Informational [Page 2]RFC 4859 Registry for RSVP-TE Session Flags April 2007
Flags from this registry may only be assigned by IETF consensus
The registry references the flags already defined as described in
Section 2 of this document.
Thanks to JP Vasseur, Bill Fenner, and Thomas Narten for reviewing
6. References6.1. 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,
[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