Subject: Re: SIP: Max-Forwards

From: "Scott Petrack"<[email-masked]>
Date: Mon, 2 Mar 1998 11:36:45 +0200

I wasn't going to pick at the name, but since Dave did, it seemed to me
that what the field was setting something like the maximum number of
entries allowed to appear in the "Via:" field.
So I would have called it Max_Vias:

(Hmm love those text protocols ;-)).

Scott

[email-masked] on 02/28/98 06:33:37 AM

To:   [email-masked], [email-masked]
cc:    (bcc: Scott Petrack)
Subject:  Re: SIP: Max-Forwards

I like the idea, but I think the name is misleading, since it has nothing
to do with call forwarding (in fact I could envision a separate feature
which limited the depth of a user-specified call forwarding path).
Perhaps something like "Request-Remaining-Hops", or "Max-Request-Forwards"
would be more illustrative.
Dave.
At 11:34 AM 2/27/98 -0500, Henning Schulzrinne wrote:
>The revision of HTTP/1.1 has a field Max-Forwards, basically like a TTL
>field (decremented at each hop, server with Max-Forwards: 0 must act on
>the request rather than proxy it.) If we want such a feature, it would
>have to be in the final protocol (*), as it would have to be implemented
>by everyone to be useful. Use in SIP context would be to avoid proxying
>altogether (I currently have a "do-not-forward" Call-Disposition header
>in the Call Control spec for this.) This can also be useful to avoid the
>merging of proxy search branches: A proxy that sends out a parallel SIP
>search would set the Max-Forwards to 0, avoiding that several requests
>reach the same destination after being merged at a downstream proxy.
>
>It's also an additional safety mechanism that prevents looping, beyond
>Via.
>
>I don't feel strongly about this either way.
>
>Comments are appreciated.
>
>(*) Not quite: it could be part of an extension signaled via Require:.
>--
>Henning Schulzrinne         email: [email-masked]
>Dept. of Computer Science   phone: +1 732 949 8344 (at Bell Labs)
>Columbia University         fax:   +1 212 666-0140
>New York, NY 10027          URL:   http://www.cs.columbia.edu/~hgs
>
>