Subject: Re: RSVP

From: "Sean Crocker" <[email-masked]>
Date: Wed, 2 Jan 2002 13:11:35 -0600

>> From an operational point of view, RSVP-TE normally requires CSPF
>> before signalling, which would in turn require IGP TE
>> configuration.  Wherever IGP TE is configured, RSVP-TE should also
>> be configured so the signalling would proceed across RSVP nodes
>> only.
>
>Not a requirement.

Emphasis on "operational point of view", as in normally network
operators will want to use CSPF before signalling and RSVP PATH
will probably never traverse non-RSVP nodes.  You've taken this
comment too literally.

>
>RSVP only requires a local forwarding table so that the next-hop address
>and interface for a given destination may be determined.
>
>How that forwarding table is generated is beyond the scope of RSVP.  It
>is usually built from an IGP of some kind, but that is not a
>requirement.
>
>> There is a non-RSVP node discovery mechanism though.  See RFC3209
>> 4.2.5.
>
>You mean RFC 2205.  Non-RSVP node discovery is part of the core RSVP,
>not part of the RSVP-TE extensions.

I meant what I said.  RFC3209 4.2.5 not only points to RFC2205 3.8,
it also makes the requirement unambiguous.

Sean

>-- David

---

From: David Charlap <[email-masked]>
Date: Wed, 02 Jan 2002 15:11:42 -0500

Sean Crocker wrote:
> 
>> You mean RFC 2205.  Non-RSVP node discovery is part of the core
>> RSVP, not part of the RSVP-TE extensions.
> 

It adds a new requirement.  Non-MPLS RSVP is designed to work with
non-RSVP routers along the path.  In RFC 2205, the detection is in order
to inform downstream nodes.

RFC 3209 makes non-RSVP nodes along the path illegal, and therefore
changes the action when one is detected (PathErr instead of setting
ADSPEC break bits).  It does not, however, change, redefine or restate
the detection algorithm.

-- David