device pool location and gateway

[shouyisun]

Centralized CCM cluster. Each site has its own location and device pool. I'll assign the same device pool and location on the gateway in the CCM as those phones in the same site. But Just for my curiosity, why we need assign device pool and location to Gateway? For example, gateway doesn't care region, right? doesn't need to care location, right? region and location are only for calls between ip phones across the wan, nothing to do with PSTN.

Thanks

[jasyoung]

Regions and locations apply to anything that will terminate a voice over IP packet stream, and gateways are definitely in this category.

Imagine a situation where you have offices and gateways in Chicago and New York. If a phone in New York calls a Chicago-local phone number, you can divert the call over your IP network to the Chicago gateway and avoid telco toll charges. This requires that you know about regions, to pick a codec, and locations, to properly maintain call admission control across the WAN.

It's also possible and even common to "tandem" a call in one gateway and out another. Imagine the same network above. Call a Chicago phone number that goes to a centralized auto-attendant. The user dials a New York subscriber whose phone is set CFwdAll to a PSTN destination in New York, perhaps their cell phone. This call will be gateway to gateway, and you continue to need to pick a codec and maintain call admission control.

[shouyisun]

Make sense.

I got a problem here: Calls from remote site PSTN to reach the opening greeting doesn't respond. I even change the remote gateway to the same location/device pool as unity, but still no luck.But remote ip phone to greeting or mailbox no problem , I see the trancoder works on the 6608 in the central.

Any thought? Btw, gw uses MGCP

Thanks