MGCP Failback/SRST

[JOEL ANDERSEN]

Do I need to have answer-address or dial-peers setup to handle inbound calls to the correct FXS port when in MGCP Failback or when it goes into SRST do those fxs ports know what extension they are.

[Erick Bergquist]

Yes, you will need dialpeers. But MGCP should have built some dialpeers for you already. You can add destination pattern to those existing dialpeers, just as long as they have application mgcpapp (service mgcpapp on newer IOS/platforms). You can create more dialpeers also for other destination numbers (like a H323 gateway).

The IP phones when in SRST will register to the router with the extension/DN on the phone, so you may need some translation rules also if inbound numbers do not match that on IP phones. You may also need connection plar to route calls on analog lines to phones.

[adignan]

Yes, I am clear on that for the IP Phones, but the FXS ports on the router don't actually "register" with router when in SRST, do they?

I am just concerned about the FXS ports when in SRST and how they retain their extension.

[Erick Bergquist]

They don't, you need dial peers with a destination-pattern and the port to route that call to.

[michael_davis]

No, they don't register per se. But when the router is in SRST mode, it is in H.323 mode. That's the purpose of the command:

call application alternate Default

'Default' means H.323, the router's native mode - when mgcpapp fails, use Default.

So you will need to configure pots dial-peers with destination patterns that equal the port's extensions for any outbound port. And you'll need outbound trunk pots dial-peers for external calls.

Finally, you'll need inbound dial-peers for voip and pots inbound legs - unless default behavior for fax, codec, etc, are ok with you.

Let me know if this helps.