Resource ReSerVation Protocol (RSVP) -- Version 1 Message Processing Rules (RFC2209)
Original Publication Date: 1997-Sep-01
Included in the Prior Art Database: 2000-Sep-13
Internet Society Requests For Comment (RFCs)
R. Braden: AUTHOR [+2]
This memo contains an algorithmic description of the rules used by an RSVP implementation for processing messages. It is intended to clarify the version 1 RSVP protocol specification.
Network Working Group R. Braden
Request For Comments: 2209 ISI
Category: Informational L. Zhang
Resource ReSerVation Protocol (RSVP) --
Version 1 Message Processing Rules
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.
This memo contains an algorithmic description of the rules used by an
RSVP implementation for processing messages. It is intended to
clarify the version 1 RSVP protocol specification.
This memo provides a generic description of the rules for the
operation of Version 1 of RSVP [RFC 2205]. It is intended to outline
a set of algorithms that will accomplish the needed function,
omitting many details.
1. GENERIC DATA STRUCTURES
This memo assumes the generic interface calls defined in [RFC 2005]
and the following data structures. An actual implementation may use
additional or different data structures and interfaces. The data
structure fields that are shown are required unless they are
explicitly labelled as optional.
o PSB -- Path State Block
Each PSB holds path state for a particular (session, sender)
pair, defined by SESSION and SENDER_TEMPLATE objects,
respectively, received in a PATH message.
PSB contents include the following values from a PATH message:
- The previous hop IP address and the Logical Interface
Handle (LIH) from a PHOP object
- The remaining IP TTL
- POLICY_DATA and/or ADSPEC objects (optional)
- Non_RSVP flag
- E_Police flag
- Local_Only flag
In addition, the PSB contains the following information provided
by routing: OutInterface_list, which is the list of outgoing
interfaces for this (sender, destination), and IncInterface,
which is the expected incoming interface. For a unicast
destination, OutInterface_list contains one entry and
IncInterface is undefined.
Note that there may be more than one PSB for the same (session,
sender) pair but different incoming interfaces. At most one of
these, which will have the Local_Only flag off, will be the PSB
used for forwarding PATH messages downstream; we will refer to
it as the "forwarding PSB" in the following. The other PSB's
will have the Local_Only flag on and an empty
OutInterface_list.h The Local_Only flag is needed to correctly
match PSB's against RSB's, by the rules of [RFC 2205].
o RSB -- Reservation State Block
Each RSB hold...