2010/6/20 Philip Prindeville <[email protected]>: > (2) When the call rings out to the cell phone, is there a header that gets > translated into SS7 that tells cell carrier being rung to not do a > forward-on-no-answer to voicemail? In the above scenario, we want the > voicemail on the PBX to answer, not the voicemail on the cell's carrier to > pick up if there's no answer. > > > There is no such specification. Voicemail serves are not a "standard", > they are just servers that automatically answer the call to bill it :) > > > Right, but forwarding from the handset to the voicemail IP (intelligence > peripheral) counts as an additional forwarding step.
No, in SIP it would be a 302 which is a SIP response rather than a new step. If the called phone would *route* the INVITE back to the proxy (by changing the RURI) then it would be a new step, but this is not what happens as phones are UA's rather than proxies. > If one sent a header saying Max-Forwards N, with a current Hop-Count as N, > then that would be sufficient to stop the additional transfer, yes? No. First of all I don't know if there is such a "Max-Forwards" header out of SIP world (as you are speaking about SS7). Anyhow, considering it exists: - Phone1 calls Phone2 through Proxy (max-forwards=1). - Proxy decrements max-forwards to 0 and routes the call to Phone2. - Phone2 doesn't answer in N seconds,or it switched off, or rejects the call by sending a 302 to redirect the call to its voicemail. - Proxy then decides to create a new branch (***so Max-Forwards remains the same***) to the voicemail server. There is no way at all to instruct the PSTN provider not to forward a call to the voicemail as such decision just depends on the called number's configuration and provider's configuration. -- Iñaki Baz Castillo <[email protected]> _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
