On Mon, 2009-06-15 at 16:48 -0400, M. Ranganathan wrote: > The private domain ( sipx.example.local ) is never visible across systems.
Of course, if Example Corp. is using "example.local", it can use sipx.atlanta.example.local and sipx.biloxi.example.local as the domain names of two different sipXecs systems. > This way you avoid name clashes. Just as a matter of curiosity, could > you tell me where this would break down? In my mind this would be a > bit easier to administer than ensuring the local DNS domains ( which > are supposed to be private and not visible outside the domain) don't > clash. > > Does our current mechanism allow each system to have its own private > domain which could be identical to that of another system? If so, then > the scheme I proposed adds nothing. If not, perhaps it does add > something but is not a good idea anyway for other reasons. > > I would like to know exactly why it breaks down. I do not wish to > re-invent the wheel so this is not a suggestion that we re-do > something that already works satisfactorily using existing mechanisms. It's difficult to say without a lot of searching where the problems might be. If sipXbridge is truly thorough in translating all SIP signaling, then by definition, there is no problem. But there are an endless number of situations where we assume that if one element writes an address, that another element can at least determine whether it understands the address (since the design of SIP has that as a general assumption). As you point out, From headers can be a problem. In theory, From headers are almost documentation. But some phones use them as the URI to call if the user applies "Call Back" to an entry from the "Received Calls" list. And the P-Asserted-Identity mechanism assumes that if the >From URI is that of a user on the local system, then the caller can provide credentials for the local SIP domain. If one system's user URIs look like the other system's user URIs, some careful coordination needs to be done to avoid trouble with that test. The two systems will crate GRUUs that are difficult to distinguish, and many elements will assume that their assigned GRUU is globally comprehensible. And consider that dialog events will carry URIs from phones on one system to phones on the other system -- does sipXbridge rewrite those completely? Etc... Dale _______________________________________________ sipx-dev mailing list [email protected] List Archive: http://list.sipfoundry.org/archive/sipx-dev Unsubscribe: http://list.sipfoundry.org/mailman/listinfo/sipx-dev sipXecs IP PBX -- http://www.sipfoundry.org/
