CUCM and Cisco 2821 H.323 gateway config doubt

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Nov 26th, 2009
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I have one server CUCM 5.0.4 and one Cisco 2821 configured as H.323 gateway in CUCM for connecting to PSTN using one E1. Also this Cisco 2821 have WAN connection.

I want to do some tests with  IP link to PSTN using an  H.323 IP Provider (NOT SIP)

Can i configure in CUCM the same Cisco 2821 two times as H.323 gateways if i configure another LAN ip address in Cisco 2821. 

I think i need to do that configuration  because IP link connection as configurations that i think will bring problems to my E1 PSTN connection. Configs like inbound/outbond faststart etc...

Is this possible? Or its better to configure  in CUCM Cisco 2821 as MGCP gateway for E1 to PSTN Connection and then configura Cisco 2821 as H323 gateway for IP Link connection for IP Provider?

Any other sugestions?


Best Regards,. 


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asandborgh Tue, 12/01/2009 - 12:18
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I'm a bit confused.  I understand that the voice traffic will go through the WAN link on the 2821 to the carrier, but the 2821 does NOT need to act as a voice gateway for this scenarion, just a WAN router.  You can very likely set up the  carrier as another IP Gateway in CCM and send the IP calls direct to them -  unless you want the 2821 to act as a CUBE to isolate your enterprise from the carrier.  In either case you don't need to mess with your existing gateway (and there is no real justification to do so either).



asandborgh Tue, 12/01/2009 - 13:40
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As a follow on to the previous post - for testing you may want to try the direct route, but for production you would be much better off using you 2821 as a CUBE to isolate your environment from the carrier.

The link is from a SIP trunk discussion but most of the points apply here as well.

The 2821 can act as both an H323 PSTN GW and CUBE simultaneously.



etmarcof Tue, 12/01/2009 - 14:02
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Hi Art,

My goal is to put 2821 as CUBE, and if tests with  H.323 Link provider goes well i will remove E1 connection to PSTN from cisco 2821.

For testing purpose i will try directly routing, because in CCM config i think i can only config one H.323GW with same IP address. Even if i configure another ip address in Cisco 2821 the  h323 bind ip address can only be configured one time, am i correct?

So in last resource for testing purposes i configure in CUCM for 2821 an mgcp gateway for E1 connection and an H.323 GW (cube) for IP link. I hope these works.

Best Regards


asandborgh Tue, 12/01/2009 - 15:09
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Yes, you can have h323 only bound to one address.  As an option, you could still use your exiting h323 gateway also as an IP2IP gateway (CUBE).  Input the allow h to h and other commands and set up the voip dial-peers to point to the carrier for certain numbers, while maintaining your present POTS dial plan for your production numbers.  I've done it in the lab without issues (not sure if it is supported, but for tetsing purposes it would be easily removed).  Your fallback plan should also work, but MGCP has it's quircks too.  Be careful with the bind commands when you first bring it up - you may have to remove the signalling bind and then re-input it once the GW is registered.  Additionally using "config server" can be sketchy too, especially if you have fractional PRI (does not support because it always builds a full E1 or T1) or if you have a power outage during a reset.  Everytime there is a reset the CCM sends down an XML file that deletes your controller.  If it hits at the same time you have an outage you have to go in and manually rebuild it - not a big thing unless it happens in the middle of the night.....

Good Luck!



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