[Sip-implementors] How to interpret To tag in 100 Trying?

[M. Ranganathan]

Dear SIP enthusiasts:

I am puzzled by the usage of the to tag parameter in a trying. The scenario is as follows:

I route an invite through a proxy.
The proxy sends a trying with a to tag assigned to the trying.
The invite gets routed to the peer.
The peer responds with ringing but the tag it uses in the To header is different than the one the proxy inserted.

The questions I have are:

1. Why would the proxy insert a To tag in the trying? What is its purpose?

2. How is the uac that sent the invite supposed to interpret the to tag. Can it safely igore the to tag in the trying?

Thanks for your replies in advance.

Regards
Ranga.

--
M. Ranganathan
N.I.S.T. Advanced Networking Technologies Division 100 Bureau Drive, Stop 8920, Gaithersburg, MD 20899

tel:301-975-3664 fax:301-590-0932
http://w3.antd.nist.gov/index.html mailto:[EMAIL PROTECTED]
Advanced Networking Technologies for the people!


_______________________________________________
Sip-implementors mailing list
[EMAIL PROTECTED]
http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors