This approach is much simpler than BFCP but I have a couple of comments. You want to make sure that people are not using 484 Address Incomplete for purposes like overlap dialing (handling features like billing codes and such). I am not sure if this proposal "semantically" alters 484 response and if the SIPPING folks will have objections to this proposal as well.....
Thanks Venkatesh 1. 484 Address incomplete has specific semantics with respect On Fri, May 30, 2008 at 12:52 PM, Alan Johnston <[EMAIL PROTECTED]> wrote: > All, > > Here is an alternative approach that utilizes sending an INVITE to > select/reserve/seize an appearance number. > > A UA that does not need to select a particular appearance number (or > doesn't care) would just send an INVITE as normal. The Appearance > Agent would tell the proxy which appearance number was being used by > inserting this information in a header field (such as a parameter in the > Alert-Info header field) in the first non-100 Trying response sent back > to the calling UA. The UA would then PUBLISH this appearance number to > the Dialog Event State Compositor for the AOR which would distribute > details of the dialog and the appearance number to the other UAs in the > group. > > If an INVITE is sent and no appearance number is available, the proxy > would reject the INVITE with a suitable response code and perhaps a > header field indication. > > A UA that does need to select a particular appearance number would use > an approach similar to overlap dialing (multi-stage dialing). An INVITE > would be sent when the appearance number is requested (i.e. when the > button is pressed, before dialing begins). The appearance number > selected would be carried in the INVITE, in a header field, for > example. The proxy would reject the INVITE with a 484 Address > Incomplete response (see RFC 3578) if the appearance number is > available. The UA could then resend the INVITE after the URI has been > dialed and then PUBLISH this appearance number to the ESC. If the > appearance number is not available, another response code such as 403 > would be sent. The user could then select a different appearance number > and resend the INVITE. > > Note that this approach does not actually require a B2BUA, but it does > require a proxy that can act as a UAS and communicate with an Appearance > Agent which keeps track of appearance number allocations. > > Comments and suggestions are most welcome! > > Thanks, > Alan > > _______________________________________________ > BLISS mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/bliss >
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