So I was recently tasked to connect to CUCM clusters to enable internal extension dialing between clusters, lets call them Site A and Site B.
By and large this was pretty straight forward, i built a SIP trunk between Cluster A and Cluster B, route patterns with site codes routing to the trunk. this part was successful, and i am able to call extensions on either side and have the call setup complete. The problem i am hitting is the audio routing piece.
Site A and Site B have conflicting internal IP space where the phones and soft phones reside, so Cluster A doesn't know how to get to Site B's phones, and Cluster B doesn't know how to get to Site A's phones, because i cannot introduce routes because of the conflict. My firewall logging is showing me that Site A's phones are trying to use Cluster B as their gateway for Site B extensions (which makes sense).
Grasping at straws is there maybe a way to do this with each site using its local cluster as the "gateway" for calls routing over the trunk?
I also explored the idea of using an H323 gateway on either side, and having the gateway route calls to the other cluster
<site a phone> dials Site B ext. <cluster a routes to h323 gateway> <site a gateway dial peer match, targets cluster b>
But in practice this did not pan out, DNA and "show dialplan number" show the call flow as correct, CCAPI debugging shows the call gets to the gateway, but it never leaves the gateway after it arrives.
I have a case open with TAC to get their assistance, but as there is time pressure, has anyone had to stand up a similar configuration? If not, any idea how i can make this work without the sites phones having to be able to reach the opposing site's call manager?
Thanks for any help you can provide.
