Subbarayalu Subbiah wrote:
> Why both UAS and proxy process the header fields (Request-Disposition
> header field Accept-Contact and Reject-Contact header fields) in a
> request?
>
> As per RFC 3841, both UAS and Proxy process the Request-Disposition
> and Preference and Capability Matching. Section 6 UAS behavior & Proxy
> Behavior mentioning this. Why proxy is processing the request? If I am
> correct, only the UAS should process the request headers & route the
> call to the matching URI.
>
> Iam bit confused of it .can any one help me to come to a conclusion.
Callerprefs, including Accept-Contact and Reject-Contact, are
*primarily* intended to be processed by a proxy when it is selecting
which contacts to consider when translating an AOR based on
registrations. (That is why the headers have the names they do.)
The processing by a UAS is to some extent a backup mechanism. If the
proxy processed the callerprefs then the UAS will simply confirm that it
was correctly selected and will proceed. OTOH, if the proxy did not
attempt to do the selection, or was unable to for some reason, then the
processing by the UAS can prevent an unintended UAS from accdeping the
request.
It is also possible for the UAS to use callerprefs as an internal
routing mechanism, for selecting among alternative software components
within the UAS itself. However that kind of use is not the concern of
the ietf.
Paul
_______________________________________________
Sip-implementors mailing list
[email protected]
https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
