Unanswered Question
Oct 20th, 2008

I have 8fxo lines on router 2811 and iwant to run mgcp by cm6.1 what commands for fxo should i use one router for example cptone is neccesary or it inherits from cm6.1????

I have this problem too.
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allan.thomas Mon, 10/20/2008 - 04:08

Is there specific requirement for using MGCP instead of H.323? The primary reason that I ask is that Caller-id is not supported for FXO ports when configured with MGCP.

If you require Caller-id then you should configure your gateway for H.323.



mehr.cco1 Tue, 08/04/2009 - 00:22

There is 3 reason for using MGCP instead of H.323 for FXO ports. first one is very important.

1-supervisory disconnect does not work in H.323, when call disconnected, FXO port released after 45 Second or when call disconnected from PSTN, IP phone continue ringing for 45 Second.

2-Central configuration of lines in Call Manager.

3-Monitoring each line in Real Time Monitoring Tools.

Nicholas Matthews Tue, 08/04/2009 - 04:39

Supervisory disconnect should work fine with H323. You've likely not set the wait-release and call-disconnect timers lower than their defaults.

MGCP controlled FXO ports are very easy to configure. You will configure some global ccm and mgcp commands, and then the router should download the rest of the configuration from CUCM.

CUCM only tells the router what to do - some things like the CPtone as you have mentioned will still be generated by the router so you will want to set this.

Here's a guide on configuring MGCP:




jaschulz Tue, 08/04/2009 - 04:45

Hey Nick, not sure if that is the right guide. It is for config of SRST. A very good one though :)

Nicholas Matthews Tue, 08/04/2009 - 05:07

It's not an exact match no, but this is the information needed from the SRST router which will also cause the FXO to register:

ccm-manager fallback-mgcp !--- For redundancy (see SRST document)

ccm-manager mgcp

ccm-manager music-on-hold

ccm-manager config server

ccm-manager config


Wilson Samuel Tue, 08/04/2009 - 06:46

Hi Nick,

Until recently I was really puzzeled how to configure the FXS Port (for Fax) and I guess this guide has really helped me a lot


Moreover, just wanted to confirm once the FXS port has been configured in the VG, is there any special comman that needs to be set mannually on the router?

Any advice would be helpful


Wilson Samuel

Nicholas Matthews Tue, 08/04/2009 - 09:11

Hi Wilson,

This is how the MGCP registration works:

You configure the router for MGCP, and ccm-manager auto-configuration.

The gateway then goes and does a TFTP request for configuration.

The gateway downloads the configuration and adds it to the running configuration.

With the running configuration, MGCP is now fully enabled and the gateway attempts to register.

So in theory you can do it two different ways:

-configure auto configuration and let the TFTP process handle all of the configuration.

-manually put the MGCP commands in to force registration. Doing this, you may or may not miss some commands or have conflicting information with what is configured in CUCM.

If you look at a PRI example, the only difference is that MGCP is activated on the PRI with the command "pri-group timeslots 1-24 service mgcp" and FXO/FXS are used by putting a pots dial peer with the port and "service mgcpapp".

The port will not register until 'service mgcpapp' is on a pots dial peer, but this should be added by default via the TFTP process.



mehr.cco1 Tue, 08/04/2009 - 22:35

Dear Nick,

wait-release default is 30Sec and call-disconnect default is 60Sec

it means FXO wait 90 Sec connected after hang up, in this period if we receive new call, FXO port is busy.

i could not solve this problem in H.323

but i solve this problem in MGCP with folowing commands :

supervisory disconnect dualtone mid-call

timeouts wait-release 5



Nicholas Matthews Wed, 08/05/2009 - 04:48

Hi Mehr,

There may have been some other problems with your configuration or a bug, but certainly supervisory disconnect isn't something that should be different operationally from MGCP and H323.



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