Subject: RE: [SIP] Proxy Routing Logic

From: Jonathan Rosenberg <[email-masked]>
Date: Tue, 19 Dec 2000 01:45:52 -0500

> -----Original Message-----
> From: Keith Robinson [mailto:[email-masked]]
> Sent: Monday, December 18, 2000 6:01 AM
> To: Billy Biggs
> Cc: SIP List
> Subject: Re: [SIP] Proxy Routing Logic
> 
> 
> 
> 
> For the first case, couldn't this be the result of a roaming 
> UA using source
> routing to get the
> initial INVITE to its home domain proxy to do the actual 
> routing (perhaps the
> user has
> originating call features registered that they wish to use); 
> in which case I
> would expect the
> behaviour in 2 to take place.

In this case, I don't think the roaming user would construct the URI in this
fashion. Rather, it would use a Route header to accomplish this task.

That aside, there is an important issue here. When using a local outbound
proxy, you most definitely do NOT want to set the maddr parameter in the
request URI to point to that proxy. This is confusing, since you would want
the URL to have the maddr parameter outside of the context of the request
URI.

Specifically, lets say I want to have a URL in a web page that causes people
to call me through some local proxy. That URL in the web page would look
like:

sip:[email-masked];maddr=local.proxy.com

This URI would not be inserted directly into the request URI, however. That
maddr needs to be stripped.

So, I propose we add some text to the spec somewhere along these lines: "The
maddr parameter should be present in the Request URI only if the server the
request is sent to is not the one in the maddr parameter.". Probably this
can be better phrased.

-Jonathan R.

---
Jonathan D. Rosenberg                       72 Eagle Rock Ave.
Chief Scientist                             First Floor
dynamicsoft                                 East Hanover, NJ 07936
[email-masked]                     FAX:   (973) 952-5050
http://www.cs.columbia.edu/~jdrosen         PHONE: (973) 952-5000
http://www.dynamicsoft.com

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---

From: Billy Biggs <[email-masked]>
Date: Tue, 19 Dec 2000 11:58:56 -0600

Jonathan Rosenberg ([email-masked]):

> Specifically, lets say I want to have a URL in a web page that causes
> people to call me through some local proxy. That URL in the web page
> would look like:
> 

  This hits my question exactly.

  I like the idea of local.proxy.com proxying the request to
[email-masked] without preconfiguring it or performing a
visitor registration at it.  Agreed?

  If so, let's revisit the idea of copying the Request-URI into the
Route and adding an maddr.

  Consider an outbound proxy which adds a record-route.  An initial
request arrives for [email-masked].  The proxy uses an RR URI:

    sip:[email-masked];maddr=outbound.proxy.com

  So, when it sees new requests with this as the request-URI, we have
different behavior dependant on if there is a Route.  This makes me
worried.

-- 
Billy Biggs, 3Com               Email: [email-masked]
http://www.div8.net/billy/      Phone: [email-masked]