Subject: RE: Making SIP HTTP/1.1 Compliant

From: Yaron Goland <[email-masked]>
Date: Tue, 28 Apr 1998 09:13:53 -0700

I think it is plausible that a user who wants to send an invitation with SIP
may be behind a firewall that doesn't support SIP but may support some type
of v/IP.

Imagine your network already supports vocal tech's or Intel's or someone
else's product but doesn't support SIP yet. No problem, you can still send
the invite via SIP (since it is just HTTP, assuming your admin allows users
to send out arbitrary methods) and then specify the vocal tech product as
the communication medium.

There are also other scenarios where your administrator may support both SIP
and v/IP but their SIP proxy sucks. After all, SIP never specified how to
actually build up its networks of proxies and hook everything together. It
is like NNTP, people have to set things up by hand. If your administrator is
lousy he may have done a bad job of it. In that case if you know a better
SIP proxy you may want to be able to skip your administrator's proxy all
together and go to another one. By using an HTTP URL the message will be
delivered to your desired proxy instead of your administrator's proxy.

Choice is a good thing.

		Yaron

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Tuesday, April 28, 1998 8:32 AM
To: Yaron Goland
Cc: [email-masked]
Subject: Re: Making SIP HTTP/1.1 Compliant

>The really cool thing about adopting HTTP URLs for the request-URI is that
>Mike could send the following message:
>
>INVITE http://sipproxy.com/proxy HTTP/1.1
>From: sip://[email-masked]
>To: sip://[email-masked]
>
>Bam! The request goes through his HTTP/1.1 proxy to his SIP proxy at
>http://sipproxy.com/proxy and gets properly handled. Joe gets his invite
and
>everyone wins.
>
>Now, you can't tell me that isn't cool. =)

This is very interesting, but probably not practically useful (at least,
not in the context you have presented it). If a user is behind a firewall
with an HTTP proxy, but his system admins haven't made provisions for a 
SIP proxy, it is unlikely that the admins have provided *any* support for
V/IP communications. I may be able to invite [email-masked] through
my HTTP proxy, but frustration ensues when we are completely unable to
set up a voice channel (unless you want us to use a persistant connection
through the proxy for streaming audio -- probably a bad idea).

I do, however, agree with you that it seems unnecessary to reinvent the
wheel. If the work required to add SIP proxy functionality to an HTTP
proxy is minimal, we'll have them deployed faster. We also avoid taking
yet another port from the increasingly crowded <1024 range.

Just my 2 cents worth...

--
Adam Roach                 |  Ph: +1 972 583 7594 | 1010 E. Arapaho, MS L-04
Ericsson Inc.              | Fax: +1 972 669 0154 | Richardson, TX 75081
[email-masked]    |                  <*> | USA