For multiport fxs IAD devices it is a burden to configure all the ports to register individually, and this also results in obsolete SIP messaging.
Instead these extensions can be defined in asterisk as non-dynamic extensions, by specifying the IP address of the IAD device and setting the SIP password empty. By doing so registration is not needed (ofcourse security will be based only on IP address and/or local LAN switch ACL policies).
The first remaining issue with this simplified configuration is that you have to define different SIP UDP ports for each fxs extension, otherwise asterisk can’t make a distinction between them for accepting outgoing calls from the IAD. By using different SIP ports (e.g. 5061,5062,…etc) this can be resolved and outgoing calls are now possible, but it would be a lot more simple if the SIP request-URI is used to identify the extension.
The second issue is that incoming calls from asterisk to the IAD are not possible for not registered IAD extensions. The problem is that Asterisk omits to put the extension number in the request-URI and only the IP address of the IAD is present, with the result that the IAD has no destination to route the call. I did no find a work-around for this, except by registering all individual ports, but that’s what I like to avoid…
For both issues the actual SIP request-URI handling in Asterisk seems causing the problem.
Besides of VoIP integrators fighting complex configurations I would think that analog multi-port IAD vendors would also be pleased with a simplified config, because a 24 or 32 port FXS IAD configuration becomes very ugly and buggy when you have to program not only all the fxs ports, but also individual SIP GW, SIP accounts + passwords, dedicated in stead of generic call routing, etc…
suggestions are very welcome