CUCM, H323 Voice Gateway config

[wilson_1234_2]

We have two main sites, HQ and DR with ten different branches in addition to the main sites.

HQ and DR have CUBE routers that carry our voice traffic to\from PSTN.

HQ, DR and all branches are using the CUBE routers as their voice gateways. Each branch has it's own voice gateway, but the route patterns are pointing the the CUBE routers for their RG.

Currently our system is the result of several different migrations that have resulted in a lack of consistency. Originally each branch had it's own PRI for local and LD calls and the local Branch gateway was configured in CUCM. SRST was originally configured at each branch.

Currently we have some branch gateways configured as MGCP, others are h323.

We will soon be upgrading our voice system to a new version and this would be a good time to clean up some of the inconsistency.   

If all of the branches are configured to use the hub site CUBE routers (HQ and DR), and there is no longer SRST configured at the branch and the branches do not have a PRI, do the branch routers need to be configured in CUCM?

The only thing that would need to be configured locally is each branch has a local POTS line in the event we loose communication the Hub sites, they will have 911 capability.

[Ayodeji Okanlawon]

Wilson,

The only to bear in mind is this: Media resoruces. Do the site have local Media resources for xcoding, conferencing and MTP etc. Please access and evaluate the design properly to determine if you will need media recources, especially MTP. If you do then it is better to have them local to the branch so you dont have this transversing the WAN. I would alos suggest that if you have this gateways at the local site, you can configure SRST on them.

We have a similar scenario with over 300 branches using centralized CUBE but we use the existing gateways from previous deployment for SRST and media resources

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[wilson_1234_2]

Thank you for the reply.

Do you have your branch routers configured as h323, or MGCP?

Also, can you show me a sample config on the local branch router as you have configured?

[Ayodeji Okanlawon]

No, We dont and you dont either. Your branch IP phones will send traffic via the CUBE to the PSTN. They have no need for thier local gateways. Hence you do not need any h323 or MGCP running on your local gateway. What you will only need is to create an SRST reference in CUCM pointing to this gateway and that doesnnt require h323 gateway or mgcp configuration. If you want to use the SRST gateways for outbound calls during a WAN outage then you will need to configure dial-peers.

Bear in mind that during SRST your inbound calls will not work, because all your DDI would have been ported to the SIP trunk

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[wilson_1234_2]

Thanks for the great information.

I was thinking there would be no need to have anything configured on the branch router if the branches are using the hub site gateways to route calls.

What about using the local routers for media resources?

Would this require CUCM config or is this configured on the local gateway?

UPDATE:

I just realized that the branches each have a FAX machine that is connected on the local gateway FXS port.

The FAX number is routed through the hub sites SIP, then to the local gateway.

[Ayodeji Okanlawon]

You need to configure this on CUCM and on the gateway using sccp.  So yes you will need to configure CUCM for this

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"'Nature is too thin a screen, the glory of the omnipresent God bursts through it everywhere"-Ralph Waldo Emerson

[wilson_1234_2]

Thanks for all of the great information, I am mainly trying to understand why these things were done a certain way.

I just realized the branches do each have a FAX line that is configured on the local gateway on an FXS port.

The number is routed from the PSTN, via SIP, through CUCM, then to the local gateway. I guess this would be why the gateways are configured in CUCM?

Or does it not have to be?

[Ayodeji Okanlawon]

Most likely. The gateways will house the FXS ports to which the faxes are connected. The fxs ports will be configured either using mgcp,sccp or h323. mgcp and sccp will need to be confugred in cucm. If you look at the config on the gateway you can see what is used to control the fxs port...

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"'Nature is too thin a screen, the glory of the omnipresent God bursts through it everywhere"-Ralph Waldo Emerson