Call Manger Integration

[Kryptkeeper]

All,

     I have any old version of Call Manger, v4.1. Anyways, I need to upgrade an MGCP gateway that is used by this CCM cluster. I have three general questions in relation to this gateway.

     Question #1: Is there an interopability matrix for CM versions and IOS code, in relation to MGCP?

     Question #2: This router in question is also running SRST. Is the version of SRST, and Call Manager co-dependant? Is there an interopability guide?

     Question #3: If I wanted to go the extra mile and do CME as SRST on that gateway, is there an interopability issue w/ CCM? Is there an interopability guide?

     Any help would be appreciated. Thanks in advance.

          -Kryptkeeper

[Steven Griffin]

Kryptkeeper,

1. Not really. MGCP is an RFC standard and as such pretty much any recent IOS (12.4 to 15.X) should work fine with CM 4.1 when it comes to MGCP.  Recent improvements to the standard that may be available in IOS won't be visible in CM 4.1 (FXO Caller ID for instance) but that shouldn't affect any functionality.
2. Officially, SRST in IOS supports specific phone load firmware, not CM versions.  In a practical application, the SCCP phone firmware that ships with CM 4.1 will work with most 12.4, 12.4T, and 15.X IOS versions.
3. CME as SRST is an exercise in pain-and-suffering, IMHO.  Unless there is an absolute business critical need to use it, stay away from it.  Why do you want to maintain two dial-plans?

-Steven

[Kryptkeeper]

uscitizen,

     My company's business continuity plan dictates that if our CMs environment goes down there has to be a backup. While reading up on SRST, I came across CME as SRST. I haven't heard anything good about SRST so I thought that CME as SRST might be a better alternative, with more features.

     What have you seen that doesn't make you like CME as SRST? Let me know when you get a chance. Good day.

          -Kryptkeeper

[Steven Griffin]

Kryptkeeper,

SRST stands for Survivable Remote Site Telephony and provides basic dial-tone service during WAN outages at remote sites where the CUCM servers are not local.   While it can provide service to the main site where your CUCMs may be  located it was never intended as a full featured phone system.   CME was intended to be a phone system on a router with all the features you'd expect in one.  

CME as SRST was created because there was a need to have hunting and other phone system level features during SRST for certain customers.  I find it to be difficult for many customers to maintain, or they just forget to maintain it, as they make normal changes in their Call Manager.  You end up having to administrate two phone systems and sometimes you are going to make a change or use a feature that is not supported in the other system.  

I find it best to use the KISS system, especially when you talk about business continuity.  If you are in a disaster, it is best to focus on what you need to survive.  In the case of a phone system basic dial-tone is what you NEED, hunt groups, extension mobility, etc... is a nice-to-have.  

Just my opinion.

-Steven

[Payal Bhaduri]

Hi,

"Cisco Unified Survivable Remote Site Telephony (SRST) does not depend upon Cisco Unified Communications Manager"

Here is the "tested-in" reference;

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/compat/ccmcompmatr.html#wp56839

To find your IOS version support check here (CME version = SRST version)

Cisco Unified CME and Cisco IOS Software Version Compatibility Matrix

http://www.cisco.com/en/US/docs/voice_ip_comm/cucme/requirements/guide/33matrix.htm