-----Original Message-----
From: Catherine Marselli [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, June 12, 2001 10:44 AM
To: [EMAIL PROTECTED]
Subject: [Sip-implementors] UA and TRIP
>Dear all,
>
>Should a terminal, which is intended to transmit calls to the PSTN, support
>something from TRIP (Telephony Routing Over IP) or is it only the problem
of
>the gateway ?
TRIP is not needed in end user phones or PC clients. It is used between
servers facing each other in a peering relationship between service
providers. Usage scenarios for TRIP are described fully in:
http://www.ietf.org/rfc/rfc2871.txt
A client or PC phone which wishes to make a call to the PSTN can do one of
several things. Starting with the most commonly implemented one:
1. If the phone is in domain foo.com, it constructs a SIP URL of the form
sip:<dialed-number>@foo.com, puts that in the request URI, and sends the
request. The server for its domain figures out what to do, using things like
ENUM, TRIP, or statically configured routing tables.
2. The phone inserts a tel URL into the request URI, of the form
tel:<dialed-number>, and sends it to its proxy. From there, things proceed
as above in step 1.
3. The phone uses ENUM itself, and possibly gets back a SIP URL for that
number, which it can use directly. If the ENUM query fails to yield a SIP
URL (which will be a frequent occurence), proceed to step 1 or 2.
-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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