On Sat, Nov 28, 2009 at 9:47 AM, Robert B <[email protected]> wrote: > I preface this with the fact that I am coming from the Asterisk world > where things are "different"... ;) > > So I am getting my head about all these various components and one thing > sort of puzzles me, and that is the media path. > > Let's say I have an sipXecs server sitting in a datacenter somewhere. > Across town I have a handful of Polycom handsets in an office who has a > business grade cable modem of somesuch. The Polycoms are configured to > register with their sipXecs PBX in my datacenter over the public Internet. > > Now, in the Asterisk world, all the RTP media would get relayed through > Asterisk and sent to the remote office. I understand this is different > in the sipXecs world (e.g. the real world) where the SIP signaling would > occur "out of band" with the RTP stream. > > Inside the office call: > > My assumption is that based on name resolution of the URI > ([email protected], [email protected]) the phones know who/what to send the > media to. (e.g. in the office, on the same LAN, it would get an internal > IP and send the call from [email protected] to [email protected]). This > is why internal DNS is critical. > > But how does this work when placing/receiving calls from an ITSP? > > Call comes in to [email protected] from the ITSP to sipXecs, the > appropriate device is notified of an incoming call and the user answers... > > Here is where my understanding just falls apart. At this stage, I have > no idea how the RTP stream "finds its way" to the device... sipxrelay? > Doesn't that sort of introduce a single point of failure? Or maybe I > just am completely wrong about all my above assumptions... ? > > Kudos to whomever can help me decipher this...
When signaling an ITSP, you have to send your call through sipxbridge ( assuming that is what you are using as your sbc ). SipXbridge will re-write various parts of the request including the following : - via header - Contact - SDP connection field. In doing that, it effectively inserts a media relay in the media path and itself in the signaling path. It is correct that sipxrelay is a "point of failure" but it is not a "single point of failure". You can have a redundant system where each server runs its own relay. If one fails the calls get routed to the other server. There is a detailed design document included with the code. Please get it from svn if interested. See sipXbridge/design/design.tar.gz Ranga. > > -- Robert > > _______________________________________________ > sipx-users mailing list [email protected] > List Archive: http://list.sipfoundry.org/archive/sipx-users > Unsubscribe: http://list.sipfoundry.org/mailman/listinfo/sipx-users > sipXecs IP PBX -- http://www.sipfoundry.org/ > -- M. Ranganathan _______________________________________________ sipx-users mailing list [email protected] List Archive: http://list.sipfoundry.org/archive/sipx-users Unsubscribe: http://list.sipfoundry.org/mailman/listinfo/sipx-users sipXecs IP PBX -- http://www.sipfoundry.org/
