Subject: [dispatch] draft-loreto-sipping-3892bis

From: "Nadia Bishai" <[email-masked]>
Date: Mon, 6 Jul 2009 13:17:37 -0400

Hi,

During the presentation of draft-loreto-sipping-3892bis-01.txt at IETF 74 in SF,
we got a question from Cullen related to the importance for a receiver to get all the identities expressions and what it does with multiple identity expressions.

The reason why multiple identity experssions are needed by the receiver is that some receivers can only handle one format of identity expression (e.g. TEL URI) and not other formats (e.g., SIP URI).  
Some examples: 
-in a Conference call, when an incoming session invitation carries the Referred-By header, the TEL URI is needed to find the corresponding contact information in the user's address book when the address book only stores telephone numbers.
- When a MESSAGE message is sent to a group where one recipient is an SMS user, the MESSAGE is intercepted by an interworking function that translates the MESSAGE into an SMS message. The SMS system can only handle a MSISDN identifier. The interworking function will use the TEL URI received in the Referred-By header to derive an MSISDN value to be sent in SMS signalling.

Nadia Bishai 
E       
E-Mail: [email-masked] 
Tel:  (+1) 514-345-7900   (X 42234)         8400 Decarie Boulevard 
Cell: (+1) 514-591-6739                          Montreal, Quebec, Canada
 www.ericsson.com                                H4P-2N2 
ECN 8105 2234