Use FXO ports from a remote site ... via SIP?

[dtbullock]

Site "BranchOffice" has 4 phone handsets and a QoS-capable WAN connection to HeadOffice.

Site "HeadOffice" has a dozen phone handsets, a SIP trunk, and Call Manager Express on a 2900 series router.

Solution: Make the 4 BranchOffice phones register with the CME in HeadOffice over the WAN link.

But: There are 2 PSTN lines terminating at BranchOffice and which can't (according to the telco) be made to terminiate at HeadOffice.  The customer doesn't want to disconnect the existing extensively-advertised and geographically-indicative numbers.

So how can calls on the PSTN lines at BrarnchOffice get incorporated into the CME hosted at HeadOffice?

A) put a CME at BranchOffice too?

B) put an FXO-SIP gateway at BranchOffice, and have CME treat it as a SIP trunk?

    i) with 3rd party gateway;

   ii) with Cisco gateway (what?)

C) something else

Design constraints:

* WAN bandwidth between offices is already a sunk cost.

* BranchOffice is unlikely to grow.

* BranchOffice's existing edge router (an 800-series) can be re-deployed.

* Ideally, HeadOffice will be able to monitor busy state of extensions in BranchOffice.

I hope that makes sense.

thanks,

David.

[paolo bevilacqua]

which can't (according to the telco) be made to terminiate at HeadOffice

Which country are you from? If you have Number Portability regulations, you must be able to port these numbers.

Other than that, you need an FXO gateway.

[dtbullock]

Which country are you from? If you have Number Portability regulations, you must be able to port these numbers.
Other than that, you need an FXO gateway.

Australia.  Regulations demand that we may retain local numbers when switching carriers, but don't demand that we can retain numbers when moving between telephone exchange areas.  http://www.dbcde.gov.au/mobile_services/number_portability

I'm sure the carriers could do it if they chose, but they prefer to charge you for 'redirection fees' if they can get away with it.

So how do I do an FXO gateway? 

My guess so far:

1. Get a 2901 with a VIC-2FXO and the IOS UC Feature Set at BranchOffice

2. at BranchOffice, setup a dial-peer with port 0/0/0 and a voip dial peer with ipv4:addr.of.voxrouter.at.headoffice

3. (optionally, to place outward calls to the PSTN attached to BranchOffice) at HeadOffice, setup a voip dial-peer with ipv4:addr.of.voxrouter.at.branchoffice

Is that the gist of it?

thanks,

David.