So I was doing some upgrades this past week adding some CMM-ACT adapters to existing Cisco CMM modules that had active PRI’s on the modules.  I had one CMM module per Catalyst 6509. 

All my PRI’s are split between these two 6509′s, and the various PRI’s belong to trunk groups (hope I got the term right) from the telco.  So, basically I can unplug any given PRI from one 6509 and the other PRI on another 6509 will still be able to take calls.

With that said I can technically take down one CMM module from one 6509 and still make and recieve calls.

So that was the plan, take down a module, install the CMM-ACT put the module back in and check make sure everything is working and repeat on the other module.

The catch of course is that if their were any calls on a PRI attached to the particular CMM well they would go down when I unplugged the PRI.  So I started researching a way to ‘busy out’ my PRI’s on the CMM I was going to work on so that it would preserve existing calls but not accept any new calls forcing them to move to the other PRI’s on the other CMM.  Doing something like this should allow me to get all calls off the PRI’s so that I can do maintenance and not incur any downtime.

I didn’t get my answers in time for my maintenance.  But I did eventually find various sources of info related to this that I look forward to try at a later time.

In CallManager it seems there is a service parameter that would help accomplish what I was trying to do.  The service parameter is:  ”Change B-Channel Maintenance Status 1 – 5″
Apparently this should allow you to take the B-channels out of service for up to five MGCP gateways without disrupting calls.

Source: Cisco CallManager Best Practices
Google Book Search Preview:  http://tinyurl.com/c5lop7

Catch is the PRI’s have to be pre-configured with “unchecking the inhibit restarts at PRI intialization” and “check enable status poll” then restart the gateway.

This Cisco doc seems to explain it fairly well.

Busy-Out ISDN B-Channels in Cisco CallManager Configuration Example
Source Cisco Website:  http://tinyurl.com/2675fo

 

Someone else also suggested, actually they asked, if the “mgcp block-newcalls” gateway config command could possibly be used in this situation.  I don’t know myself but its worth trying one day.  Still waiting to see if anyone comments on his question in which case I will add that info here as well.