unicast
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...
If the client sent the request via unicast UDP, the response is sent
to the address contained in the next Via header field ...
... media
types and formats that are allowed to be distributed to that session.
For a unicast session, the session description enumerates the media
types and formats that the caller ...
... description if it is unable to receive the media indicated in the
caller's description or wants to receive data via unicast.
...
... capabilities of new arrivals to a conference, add or delete media or
change from a unicast to a multicast conference.)
...
... multicast.
331 Unicast not available: The site where the user is located does
not support unicast communication (usually due to the presence
...
... 331 Unicast not available: The site where the user is located does
not support unicast communication (usually due to the presence
of a firewall).
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... Unicast UDP ...
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Proxies in this category issue at most a single unicast request for
each incoming SIP request, that is, they do not "fork" requests.
...
... state
can be freed) when all requests have been answered by final status
responses (for unicast) or 60 seconds have elapsed (for multicast). A
proxy ...
... The interpretation of send-only and receive-only for multicast media
sessions differs from that for unicast sessions. For multicast,
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