Subject: [SIP] question about branch field

From: "Roland" <[email-masked]>
Date: Thu, 8 Mar 2001 11:39:18 -0800

the branch field in the via header has two parts. 
according to the rfc2543, the first part is for loop check:
            The "branch" parameter MUST depend on the incoming request-URI to distinguish looped requests from re-quests

            whose request-URI is changed and which then reach a server visited earlier.

since request-URI is only information to check loop by branch, so the first branch part only encode request-URI ?

the second part seems for seeking the corresponding request. so Which information should be encoded inside?

a branch in some document such as 7a83e5750418bce23d5106b4c06cc632.1. Which part is for loop-check?

which part is for matching a previous request? why the second part usually only has small information?

thanks,

roland