[asterisk-users] server farm workarounds? (was Re: Restrict SIP registration to one ip address only?)

[JD]

Apparently I mis-interpreted was the original poster was wanting. Good 
thing. I'm glad he has a solid answer.

But, this does bring up the my issue of yore, and I'd be curious how 
people have handled this. Key items:

* It's a distributed server farm. There are N asterisk servers serving 
hundreds of customers, each with dozens of extensions. For the sake of 
this example, I'll just pretend there are 3 asterisk boxes.

* It's distributed. It's not a primary/failover. It should not matter 
which asterisk box takes an incoming call from the PSTN. Each server is 
independent and does not require that the other servers be operating.

* Each asterisk box should be able to send a call to each SIP CPE 
(Polycom 550, etc.) directly.

* Nearly every SIP CPE I have encountered requires that it register 
before making calls. Most support multiple registration profiles for 
redundancy, however, none of them will actually register with more than 
one server at the same time.

* Nearly every SIP CPE I have encountered has a "permissive" mode of 
some kind that allows it to take calls from multiple IP addresses.

* Network problems and CPE problems (such as people unplugging their 
phone) do happen, so it's important that the asterisk box know if a 
phone is up or not. (Timing out is problematic and takes a while.)

And, the problem:

* Asterisk does not seem to have a way to monitor an extension (peer) 
that might also be used to register. In other words, a registrable peer 
ignores the 'qualify=yes' setting.

* Using two peer entries in sip.conf for the same CPE (one registrable 
and one static/qualified) creates some bad scenarios on transfers, 
conference calls, and other applications.

Ideas? How have others gotten around this restriction?

Ironically, all the problems would go away if a registrable peers could 
use qualify=yes. It's almost a bug.

Thanks,

John