Multiple CallManager Groups and Registration?

Unanswered Question
Jul 14th, 2008

We've been having issues over the past several months with our WAN connection going down, and all of our phones at the remote office trying to register and run across our backup 10meg line, which of course isn't making things very happy. When our system was setup by our VAR, they configured us to have one CallManager (CCM5.1) group, with a publisher at the remote office, and the subscriber here at the main office.

Is it possible to split that out into two groups? What I'm looking at doing is having both groups set to register to the subscriber here at the main office, and in the event of a WAN issue, manually changing priority on one group to register the phones directly to the publisher. Would that work at all? How much of an overhaul would it be to split one group into two? Would it even work, would changing the registration priority cause the phones to automatically re-register?


I have this problem too.
0 votes
  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 5 (3 ratings)
rob.huffman Mon, 07/14/2008 - 10:10

Hi John,

This is a very possible change, by design, you can specify where a phone registers by assigning it to a specific Device Pool this in turn will look at a Callmanager Group that lists a Primary, Secondary and Tertiary Callmanager server. You may need to setup both, a new Device Pool and a new Callmanager Group.

Here is some related info;

Cisco Unified CallManager groups and device pools represent logical groupings of devices that you can arrange in any way that you want. For ease of administration, make sure that all the devices in a group or pool share a common and easily identified characteristic, such as their physical location on the network.

You can also use Cisco Unified CallManager groups to establish redundancy (backup call processors) for the primary Cisco Unified CallManager in the group. A Cisco Unified CallManager group comprises an ordered list of up to three Cisco Unified CallManager servers. During normal operation, the first (primary) Cisco Unified CallManager in the group controls all device pools and devices that are assigned to that group. If the primary Cisco Unified CallManager in a group fails, control of the device pools and devices that are registered with the primary Cisco Unified CallManager transfers to the next Cisco Unified CallManager in the group list.

From this good doc;

Cisco Unified CallManager Groups

A Cisco Unified CallManager group comprises a prioritized list of up to three Cisco Unified CallManagers. The first Cisco Unified CallManager in the list serves as the primary Cisco Unified CallManager for that group, and the other members of the group serve as secondary (backup) Cisco Unified CallManagers.

Cisco Unified CallManager groups associate with devices through device pools. Each device belongs to a device pool, and each device pool specifies the Cisco Unified CallManager group for all of its devices.

Cisco Unified CallManager Groups:

Call processing load balancing You can configure device pools and Cisco Unified CallManager groups to distribute the control of devices across multiple Cisco Unified CallManagers.

Device Pools

Device pools provide a convenient way to define a set of common characteristics that can be assigned to devices.

Hope this helps!


Jaime Valencia Mon, 07/14/2008 - 10:10

yes, you can create (and are supposed to) several CUCM groups so always the primary server is on the same site as the phones and secondary maybe over WAN.

create as many CUCM groups as needed and also create device pools as needed per location.

you cannot change priority manually, you create the group and specify the order on which phones will try to use servers

of course changing the group would cause phones to re-register according to the new config, you need to reset phones for this to work.

EDIT: Rob i can only cry for my lame typing skills =)



if this helps, please rate

jvweigand Mon, 07/14/2008 - 10:17

Thanks so much guys, I really appreciate the info.

That was my biggest question, if manually changing the priority would cause a re-registration without a reset - good to know it doesn't.

If I'm going to make these changes, I should repoint the route lists for the remote site to the new group as well, correct?

Final question: as a rule, phones should not be registered to the publisher except when absolutely necessary, correct?

Thanks again for all the help!

Jaime Valencia Mon, 07/14/2008 - 10:28

usually you have a GW at each location for local calls and the necessary route lists will register to the local server so the answer would be yes. if you only have 1 GW or only at 1 location then it would really not matter since the route list would register to the other server.

and yes to the 2nd one, since the PUB handles the main DB it's always recommended to avoid having phones register to it, you can still have it as the last option in case of failure of all other servers, but if possible avoid doing so



if this helps, please rate


This Discussion