From: "V.S.R Kumar Kadimcherla" <[EMAIL PROTECTED]>

   When a stateful proxy has received 302 responses from all the down
   stream client transactions and received some contacts in those
   responses then proxy is sending 300 response to the upstream by
   appending the all contacts received in 302 responses in to the
   contact header field. Proxy is not looking for any duplication of
   contacts before forwarding the 300 response. Is it a valid
   behavior?

   Elimination of duplicate entries is duty of the proxy or end point
   has to take care of this?

I don't think that RFC 3261 even allows a proxy to aggregate 3xx
responses it receives into one 3xx response to send upstream, but it
does seem to be the correct thing to do if the proxy does not want to
implement 3xx on its own.  (But it's not clear why it wouldn't since
the proxy already implements forking.)

IIRC, a SIP element that does forking is required to not sent multiple
requests to the same target URI regardless of how the target set is
constructed, so it should be ignoring duplicate Contact values in any
3xx it receives.  So it seems that it is safe for the aggregating
proxy to not check for duplicate Contacts.  But a forking proxy
already must implement the URI-comparison operation, so it shouldn't
be hard for it to delete duplicates as it is aggregating 3xx
responses.

Dale
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