El Jueves, 29 de Enero de 2009, Klaus Darilion escribió: > The enterprise has many assigned phone numbers (DIDs) which will be > forwarded by the service provider to the contact registered by the PBX. > > Problem: How to signal the called phone number? Usually the called phone > number is in the RURI, but the service provider retargets the RURI with > the REGISTER contact, thus this information is lost. > > We found this workarounds: > > * To: header: the called number is placed in the to header: Ugly, PBX > have to route based on To header, .....
Never, the TO header could be the original destination of the call. If a diversion occured then the TO still would point to the original target. Also the TO can arrive in very exotic ways: To: sip:001234...@xxxxx To: sip:+1234...@xxxxx To: sip:1234...@xxxxx To: sip:01234...@xxxxx ... > * RURI: The service provider uses only the host part of the REGISTER > contact and puts the phone number into userpart of the RURI when > retargeting. Not standard conform, ..... (I think this is was SIPConnect > suggests) It would break registration from normal phones which expect the same RURI username as the user they used in the registration. > * RFC 3455: P-Called-Party-ID No idea. > * routing instead of retargeting: called number in RURI, REGISTER > contact in Route header I don't like. > Any other workarounds left? Yes: a) The PBX could register as many times as DID has assigned, using the appropiate DID for each registration. b) The provider could add a custom header containing the AoR for which the user location was performed. I wrote sometime ago about it: https://lists.cs.columbia.edu/pipermail/sip-implementors/2008-August/020215.html I deployed a small SIP provider with OpenSer using this custom mechanism to allow multiple DID per PBX (so the PBX needs to extract the custom header value when receiving an INVITE from the SIP provider). > So what is the preferred mechanism? What do vendors and service > providers implement? What should we implement in Asterisk? IMHO the most correct mechanims would be a) but it wouldn't be escalable if lots of DID are assigend to the PBX. Regards. -- Iñaki Baz Castillo _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
