Subject: [SIP] Usage of DNS SRV query

From: Shail Bhatnagar <[email-masked]>
Date: Mon, 17 Jul 2000 13:00:51 -0400

A proxy can route a request using different mechanisms like :

(a) Route header in incoming request

(b) Contact headers obtained from REGISTER messages

(c) Contact headers obtained from 3xx response

(d) Outgoing Request-URI is same as incoming Request-URI ( it got a 
call for a foreign domain or host portion of incoming Request-URI
is not the proxy)

and there may be/are others. Should a proxy use the DNS SRV query
for all the above cases. 
I guess, SRV query should not be used if proxy has some static 
routes or information that it uses for call routing.

Comments ??

-- 
Best regards,
Shail

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From: Jonathan Rosenberg <[email-masked]>
Date: Tue, 18 Jul 2000 01:53:44 -0400

> call for a foreign domain or host portion of incoming Request-URI

Any location other location service can be used as well - LDAP database,
for example.

> and there may be/are others. Should a proxy use the DNS SRV query

Yes.

> routes or information that it uses for call routing.

Not neccesarily. I might have a static route that maps calls to +1 973
to gateways.com:

INVITE tel:19735551212 SIP/2.0 ---> INVITE sip:[email-masked]

where the actual ip address of gateways.com is obatined from DNS.

-Jonathan R.

-- 
Jonathan D. Rosenberg                       72 Eagle Rock Ave.
Chief Scientist                             First Floor
dynamicsoft                                 East Hanover, NJ 07936
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