The MPLS WG Archive

["Hong Liao" <hliao@telcordia.com>]

David,

Thanks for your quick reply.

Since rsvp is not route-to-route protocol, it is possible for some systems which
does not support raw network I/O, it will use UDP encapsulation.

Thanks in advance.

Julia





David Charlap <david.charlap@marconi.com> on 02/28/2001 02:04:17 PM

To:   Hong Liao <hliao@telcordia.com>
cc:    (bcc: Hong Liao/Telcordia)
Subject:  Re: rsvp udp connection




Hong Liao wrote:
>
> When rsvp package is sent out, was UDP connection required?

No.

> According to the spec 2205, on Appendix c., it means that there are
> two different scenarios.
> One is that the rsvp can send and receive by raw network I/O, and
> another one is that UDP is necessary to put RSVP into the UDP before
> it is sent out.  When we do the real testing, it looks like that the
> rsvp only require raw network I/O to send and receive IP datagrams
> using protocol 46.
>
> Can anyone tell me which way is the most of switches( supported rsvp
> )implemented?

RSVP, as defined in RFC 2205, is a host-to-host protocol, not router-
to-router.  The hosts may run RSVP as an application-level protocol, and
not as a part of the OS network stack.  As such, it may be unable to
generate or receive IP packets other than TCP and UDP.  UDP
encapsulation is a workaround to allow these kinds of hosts to use RSVP.

UDP encapsulation should not be required for router-to-router
communication, such as when it is used in MPLS.

-- David