Hi Openpbx-users, I want to start a discussion on a - in my opinion - existing problem with "roaming" SIP users. Let's describe the problem: Guess we have two locations at our company. Each location has it's own SIP proxy (siteA.mydomain.tld and siteB.mydomain.tld) and users homed at one of theses two proxys. Thus users can register at their home registration server (their home proxy). So each user can be reached via sip:<user>@<proxy-at-site>. If the user is at this desk there is no problem. In case of an arriving call the UA at the registered IP of the user is invited via SIP. So the call get's established.
Let's guess userA from siteA (sip:[EMAIL PROTECTED]) moves temporary to siteB, because he has a job to do at this site. Then he has a few possibilitys: (a) set a call redirection at his phone (so the phone sends a "temporarily moved" message to the proxy, the proxy can redirect the invite to his new location e.g. [EMAIL PROTECTED]) (b) ask his administrator for setting a static redirect at the location server (proxy) at siteA so that it redirects the invite to his new location e.g. [EMAIL PROTECTED] (c) use a protocol like DUNDI to find the user in the list of peered location server (proxys) to redirect the call to these address. (TRIP also can't solve the problem) (d) use ENUM and alter the NAPTR record to e.g. [EMAIL PROTECTED] (would only work if a call arrives at his e.164 number, not for "direct" calls to [EMAIL PROTECTED]) In my opinion all these posibilities are less satisfactory. The most interesting thing is a "static" redirect from the proxy server of the users home location (proxy siteA.mydomain.tld), but the users administrator would beat us to death. If we use the redirect from the phone (384 moved temporary) the phone needs to stay connected to the network (if we use a softphone or want to use the hardphone for other purposes then the invite could not be handled by the phone and the proxy doesn't get informed about the moved user). DUNDI would not make it possible to support a user moving out of the dundi administrative domain (e.g the user went out to work at home and has his sip client at home registerd with a sip provider, e.g. [EMAIL PROTECTED]) and ENUM would not cover directed calls to [EMAIL PROTECTED] I think it would be great if we would have a sip command that the authenticated user could send to his home registration server (proxy or location server at siteA) and tell this server where the user has temporary moved to. This is more efficient than setting this at the phone, because of the phone can be turned of or temporary used by another user from siteA. The same procedure is well known from conventional PBX distributors. They store the redirect information provided from the user to the phone in the PBX. So if you disconnect the phone the call redirection is still active. I have searched the web for a similar possibility in the SIP RFCs, but found no coresponding function. Does someone knows if this is still covered by any RFC? How do you think about this idea for a SIP command that can provide this functionality? Thanks for your comments and thoughts on this topic... Best regards, Werner -- Mit freundlichen Grüßen Werner Rades -------------------------- BCA-Services Ltd. IT-Department Dachauer Str. 20 80335 München Tel. +49 (89) 54 54 96 19 Fax. +49 (89) 54 54 96 20 Mobil +49 (175) 20 86 158 eMail [EMAIL PROTECTED] Web: http://www.bca-itservices.com _______________________________________________ Openpbx-users mailing list [email protected] http://lists.openpbx.org/mailman/listinfo/openpbx-users
