Andreas,
ACK for a 200 OK is different from an ACK for a non-200 OK. ACK for a 200 OK
is considered a separate transaction and is part of the INVITE-200 OK-ACK handshake.
It should therefore be traversed end to end, whether that is directly between clients
or through proxies (RR). An ACK for a non-200 OK is part of the same transaction, and
is dealt with on a hop-by-hop basis.
Regards,
Chris.
>-----Original Message-----
>From: Andreas Bystr�m [mailto:[EMAIL PROTECTED]
>Sent: 20 March 2003 08:53
>To: Sip Implemators
>Subject: [Sip-implementors] Question regarding ACK hop-by-hop
>
>Hi!
>
>When is ACK hop-by-hop or forwarded? In draft
>"draft-ietf-sipping-basic-call-flows-01", example 3.2 (an successful call)
>the ACK on the 200 OK is forwarded by the proxies. In example 3.8 and 3.9
>(unsuccessful call, no answer and busy) the ACK is forwarded hop-by-hop. Is
>there some simple rule for how to forward ACK?
>
>If the ACK request is hop-by-hop, how do a statless proxy know when to
>forward it or not? Looking at the previous mentioned examples, I can see
>nothing in the ACK sent from A to Proxy 1 that says to the proxy "don't
>forward this". How is this solved?
>
>Regards,
>
>Andreas
>
>
>____________________________________
>Andreas Bystr�m
>Computer Engineer
>
>e-horizon Streaming Technologies
>Stadshusplatsen 2, 4th floor
>Box 172
>SE 14922 Nyn�shamn
>
>mail : [EMAIL PROTECTED]
>web : www.e-horizon.se
>phone : +46 8 524 201 80
>mobile: +46 708 85 23 35
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>
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