CallManager with NFAS PRI on Gateway is limited to 23 Voice Calls

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Jun 5th, 2007
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I posted this on this board since I think our Voice Gateway's configuration for T1 PRI NFAS signalling is correct. We have 2 T1s configured as NFAS and we can use the PSTN. When I issue the command "sh voice call stat", I can see the number of active calls in the ISDN. When I issue the command "sh isdn service", I can see that calls are distributed to both T1s and corresponds the actual number of active calls. When I issue the command "sh isdn nfas group 1", it correctly shows me the number of available B channels, which is 46 minus number of active calls.

However, the problem I am having is in Call Manager, whenever we reach 23 active calls in the Voice Gateway, the Route List in Call Manager fails over to the other Route Group defined in the Rouote List. Which essentially means that eventhough we have 2 T1s and we should be able to have 46 calls (both D channels are used, 1 Primary and 1 Backup), we're limited to 23 calls (B channels). Any idea? Thanks.

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espereir Sun, 06/10/2007 - 13:11
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I believe that you have MGCP, as a matter of fact, NFAS is not supported with CCM and MGCP gateways, you will need to migrate this to H323 in order to use the NFAS functionality or have a D-channel per PRI in order to avoid this problem.

Check these links:

Hope this helps!

junp14 Sun, 06/10/2007 - 13:45
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Nope, we're using H323. As I stated in my first post, the NFAS is working it's just we're limited to 23 calls. Thanks.


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