Technical Summary
This document replaces and obsoletes RFC 4420. The only change is
in the encoding of the Type-Length-Variable (TLV) data structures.
This allows consistency with the use of TLV data structures in other
related documents, and therefore essentially corrects a bug in 4420.
Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) may
be established using the Resource Reservation Protocol Traffic
Engineering (RSVP-TE) extensions. This protocol includes an object
(the SESSION_ATTRIBUTE object) that carries a Flags field used to
indicate options and attributes of the LSP. That Flags field has
eight bits allowing for eight options to be set. Recent proposals in
many documents that extend RSVP-TE have suggested uses for each of
the previously unused bits.
This document defines a new object for RSVP-TE messages that allows
the signaling of further attribute bits and also the carriage of
arbitrary attribute parameters to make RSVP-TE easily extensible to
support new requirements. Additionally, this document defines a way
to record the attributes applied to the LSP on a hop-by-hop basis.
The object mechanisms defined in this document are equally applicable
to Generalized MPLS (GMPLS) Packet Switch Capable (PSC) LSPs and to
GMPLS non-PSC LSPs.
Working Group Summary
This document corrects a bug in RFC4220 which was found during
interoperability testing. Once this bug was found, there was no
controversy regarding how to fix this.
Document Quality
Current implementations are compatible with this document
(and therefore no longer compatible with one detail in RFC4220).
Personnel
Deborah Brungard is the document shepherd. Ross Callon is the
responsible AD.
RFC Editor Note
Please update section 3 as follows:
OLD
Length
Indicates the total length of the TLV, i.e., 4 + the length of
the value field in octets. A value field whose length is not a
multiple of four MUST be zero-padded so that the TLV is four-
octet aligned.
Value
The data for the TLV padded as described above.
NEW
Length
Indicates the total length of the TLV in octets. That is the
combined length of the Type, Length, and Value fields, i.e.,
four plus the length of the Value field in octets.
The entire TLV MUST be padded with between zero and three
trailing zeros to make it four-octet aligned. The Length field
does not count any padding.
Value
The data carried in the TLV.