Does NFAS work on Call Manager 1

[Ski123]

Does the Cisco Call Manager work with T1's set up in an NFAS configuration ? Meaning If you have a Primary D channel on one T1 and a Backup D channel on another or does each T1 circuit have to have its own independant D channel?

 

[phrk]

Ski123. Good question. I was wondering about CUCM's abilty to handle NFAS and multiple PRIs, too. I posed this question to a CCIE last year and we looked it up.

Cisco does support this feature:

http://www.cisco.com/en/US/docs/ios/11_3/feature/guide/nfas.html

However, one big caveat for Call Manager not mentioned in the link above is that the gateway where the T1s terminate must be configured as H.323 to support NFAS. An MGCP gateway did not support this feature in the past. MGCP protocol backhauls D-channel info to Call Manager which is why we were told NFAS would not work with the MGCP protocol. Not sure if this is still true. I'll post If I find more relevant info.

 

[Ski123]

I did get some info from a Cisco engineer that said NFAS is supported on 3800 series and certain other routers. I need to find out about MGCP because that is how they will be configured.

 

[phrk]

This has the answer i believe:

https://supportwiki.cisco.com/ViewW...configure_NFAS_with_MGCP_in_Cisco_CallManager

 

[whykap]

There was also a limitation of three PRI's bundled together sharing primary/secondary D-channel. This might have also changed lately but it used to be that way up until a year ago or so.

 

[HmmG3]

We had a bundle of 9 PRIs in a NFAS with a primary and a secondary D-channel The 3845 router handled it just fine. H.323 was required to get it to work.

We are now in the process of removing NFAS since we prefer MGCP for our location and wanted to distribute that group of T-1s over multiple gateways. We only used NFAS in the past because our Avaya supported it across multiple EPN locations and it saved us a few bucks. With Cisco, it's not as good.

 

[jeter]

HmmG3 is correct!!! Here's a Star for your time!!!


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