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Configuring 924e with Transparent Proxy and FXO for local calls

Here is my situation.

We are a Rural Telco that has launched Hosted PBX.  Hosted is on a MetaSwitch platform.

We have a bank with several local branches in our service area and one branch outside our service area.  We do not plan to apply to be a CLEC for that area.

We have a leased circuit between the Branch and our Metaswitch.

I want to use a 924e (16 FXS/8FXO) in this application.  924e would act as a proxy (transparent?) at the remote site.  Local calls at that branch would route out the FXO ports.  Also, incoming calls coming into the FXO ports would need to route to local ip phones. 4 digit dialing would go out the SIP Trunk.  Long Distance? Well, that can probably go out either the SIP Trunk or local FXO.

I am using the following document as a template -

Hosted SIP Phones with Full FXO Survivability and Full-time FXO Usage Sample Configuration

This is what is confusing in this document -

The SIP server will need to be provisioned to terminate a SIP trunk from the AOS device.  When not in survivability, all calls destined to the FXO or originating from the FXO will need to be routed through the SIP server. 

It is not permissible for calls to bypass the SIP server under non-failover conditions.

Does this mean I will have to route all the calls coming in or out  the local FXO through the lease line and back?  Is there a better option?

Any config examples would be greatly appreciated..


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Honored Contributor
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Re: Configuring 924e with Transparent Proxy and FXO for local calls

We have done something similar but the softswitch is Broadworks. We take incoming calls from the FXO and send them out SIP to the softswitch. This way the switch can handle transfers, auto-attendant, and the like. The one-off location is part of the customer dialplan and things will work better that way.

If you want to keep outbound local calls from that branch on the FXO rather than backhauling to your softswitch, there's a trick to do that. operationally there are advantages and disadvantages. Keeping them local reduces traffic on your point-to-point line if it's congested. Pushing everything back through the softswitch is operationally cleaner to troubleshoot. Another advantage to sending all outbound back through your softswitch is that the local telco charges for message units on outbound local analog POTS lines is often substantially more than hauling them over SIP anywhere in the country.

The trick to routing local outbound calls over the FXO is to put the local calling patterns in the TA924e dialplan under the category "Always permitted". This is interpreted by the TA924e the same as 9-1-1 and those calls will be routed out the local FXO at all times. It isn't well documented but it works. Personally I'd send all outbound including local through your softswitch unless the point-to-point circuit is going to be congested. This way the local FXOs are available for incoming calls.