The MPLS WG Archive

[David Charlap <david.charlap@marconi.com>]

Feng, Mark wrote:
 >
 > I think it is part of the requirement for RSVP.
 >
 > Following is the description for the particular parameter:
 > "              -    Source_Address
 >
 >                    This is the address of the interface from which the
 >                    data will be sent.  If it is omitted, a default
 >                    interface will be used.  This parameter is needed
 >                    only on a multihomed sender host."

This is describing a parameter for an application-to-stack API call.  It
defines the interface that the Path message willcome from.  It doesn't
say a thing about whether that interface's address must appear in the
SENDER_TEMPLATE object.

 > Following is the excerpt from section 3.11.5
 >
 > "         o    Outgoing Link Specification
 >
 >               RSVP must be able to force a (multicast) datagram to be
 >               sent on a specific outgoing real or virtual link,
 >               bypassing the normal routing mechanism.  A virtual link
 >               might be a multicast tunnel, for example.  Outgoing link
 >               specification is necessary to send different versions of
 >               an outgoing Path message on different interfaces, and to
 >               avoid routing loops in some cases.

This is not an RSVP protocol requirement.  This is a requirement that an
IP stack must meet in order to be possible to implement RSVP over it.

 >          o    Source Address and TTL Specification
 >
 >               RSVP must be able to specify the IP source address and
 >               IP TTL to be used when sending Path messages."

Again, this isn't a requirement for RSVP, but is a requirement for an IP
stack, in order to be possible to implement RSVP over it.

-- David