> -----Original Message-----
> From: Ghai, Rajat (Rajat) [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, July 26, 2001 2:07 PM
> To: [EMAIL PROTECTED]
> Subject: RE: [Sip-implementors] How can I locate the proxy server ?
>
>
> > >-----Original Message-----
> > >From: M Taqi Asfar [mailto:[EMAIL PROTECTED]]
> > >Sent: Thursday, July 26, 2001 6:20 AM
> > >To: [EMAIL PROTECTED]
> > >Subject: [Sip-implementors] How can I locate the proxy server ?
> > >
> > >
> > >
> > >Hi,
> > >
> > >I have developed a SIP-based soft-phone. And now I am
> > >developing a proxy
> > >server. For that I am a bit confused about role of the
> > >requestline-uri
> > >present in the INVITE message.
> > >
> > >I am having the following configuration -
> > >
> > >I have a UAC running at IP address
> > >-157.227.2.59
> > >
> > >I have a UAS running at IP address -
> > >157.227.2.61
> > >And my SIP proxy server is running at IP address - 157.227.2.100
> > >
> > >Now I want to call the UAS through the proxy.
> > >What would be my request-uri in this case ?
>
>
> Your request-uri would like sip:[EMAIL PROTECTED]
> please note that user is optional.
There are two different configurations which are being confused in this
thread. In the more common configuration, the caller A wishes to call some
user B. User B is in domain foo.com (sip:[EMAIL PROTECTED]). There is a proxy for
foo.com, and user B registers at that proxy. B is the UAS for the call in
question. Its registration will look like:
REGISTER sip:foo.com
From: sip:[EMAIL PROTECTED]
To: sip:[EMAIL PROTECTED]
Contact: sip:[EMAIL PROTECTED]
Now, if A calls B, A sends the request to foo.com (157.227.2.100) which is a
SIP proxy for that domain. The INVITE request line would look like:
INVITE sip:[EMAIL PROTECTED] SIP/2.0
which goes to the proxy. The proxy looks up sip:[EMAIL PROTECTED] and finds a
matching registration, and so forwards it to sip:[EMAIL PROTECTED] Now, that
whole thing could be done using IP addresses instead of domain names, so
that foo.com is replaced by 157.227.2.100 everywhere above.
The second configuration is where A knows the IP address of B's UA, but is
using a local outbound proxy. In that case, the INVITE will look like:
INVITE sip:[EMAIL PROTECTED] SIP/2.0
and this is sent to the proxy 157.227.2.100, which is the *callers* proxy,
not the called parties. So, the proxy forwards the request directly to the
user in the request URI, which is B's machine.
This second case is not common, since A will not usually know the IP address
of B. In the first case, domain names will usually be used, not IP
addresses.
-Jonathan R.
---
Jonathan D. Rosenberg, Ph.D. 72 Eagle Rock Ave.
Chief Scientist First Floor
dynamicsoft East Hanover, NJ 07936
[EMAIL PROTECTED] FAX: (973) 952-5050
http://www.jdrosen.net PHONE: (973) 952-5000
http://www.dynamicsoft.com
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