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New Member

Help configuring DNS on CallManager 6.1

I'm new to cisco VoIP and also new to the company I am at so I am unaware of what to look for.

I need to change the DNS configuration on the call managers on our network.

We have 1 publisher and 3 subscribers, managing about 2000 phones in total.

I have read documentation online on how to change the DNS configurations, and that I need to restart the Tomcat service, and also restart the server.

My concern is failover issues.

What I want to know is, what happens when I change the DNS on one call manager and then reboot it. Will those phones be out of service while it reboots or will they failover temporarily to another subscriber?

Likewise, what happens when I change the settings on the Publisher?

Call Manager is version 6.1.3

6 REPLIES

Help configuring DNS on CallManager 6.1

Hi Sean,

Cisco Unified CallManager Redundancy Groups

Groups and clusters form logical collections of Cisco Unified  CallManager servers and their associated devices. Groups and clusters do  not necessarily relate to the physical locations of any of their  members. A group comprises a prioritized list of up to three Cisco  Unified CallManager servers. You can associate each group with one or  more device pools to provide call-processing redundancy. You use Cisco  Unified CallManager Administration to define the groups, to specify  which Cisco Unified CallManager servers belong to each group, and to  assign a Cisco Unified CallManager group to each device pool. Each group  must contain a primary Cisco Unified CallManager, and it may contain  one or two backup Cisco Unified CallManager servers. The order in which  you list the Cisco Unified CallManager servers in a group determines the  priority order.

Cisco Unified CallManager groups provide both redundancy and recovery:

Failover—Occurs  when the primary Cisco Unified CallManager in a group fails, and the  devices reregister with the backup Cisco Unified CallManager in that  group.

Fallback—Occurs  when a failed primary Cisco Unified CallManager comes back into  service, and the devices in that group reregister with the primary Cisco  Unified CallManager.

Under normal operation, the primary Cisco Unified CallManager in a group  controls call processing for all the registered devices (such as phones  and gateways) that are associated with that group.

If the primary Cisco Unified CallManager fails for any reason, the first  backup Cisco Unified CallManager in the group takes control of the  devices that were registered with the primary Cisco Unified CallManager.  If you specify a second backup Cisco Unified CallManager for the group,  it takes control of the devices if both the primary and the first  backup Cisco Unified CallManager servers fail.

When a failed primary Cisco Unified CallManager comes back into service,  it takes control of the group again, and the devices in that group  automatically reregister with the primary Cisco Unified CallManager.

Reference:

http://www.cisco.com/en/US/docs/voice_ip_comm/uc_system/UC5.0.1/ipt_system_arch/COL_FFR.html

Hope it helps.

Anand

Please rate helpful posts !!

New Member

Help configuring DNS on CallManager 6.1

Thank you, could you possibly answer another question or two?

Since I want to change the DNS on the call managers, in what order should I do it? Publisher first? or Subscriber first?

I was told the last time this was attempted at this business that after DNS servers were changed and the machines rebooted, the Call managers wouldn't talk to one another anymore.

Are there steps to avoid this?

Help configuring DNS on CallManager 6.1

Hi Sean,

Please use the below link,

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_configuration_example09186a0080a9a0fe.shtml

Also please don't forget to rate all the helpful posts by clicking on the stars below each of the right answers !!

Thanks,

Anand

New Member

Help configuring DNS on CallManager 6.1

One more question;

I cannot find any information regarding whether I should change the DNS settings on the Publisher first, or ont he subscribers.

Recomendations?

Cisco Employee

Help configuring DNS on CallManager 6.1

AFAIK it really shouldn't make any difference on which one you start.

HTH

java

if this helps, please rate

www.cisco.com/go/pdihelpdesk

HTH

java

if this helps, please rate

www.cisco.com/go/pdi
Cisco Employee

Re:Help configuring DNS on CallManager 6.1

Ideally as Jamie said it shouldn't matter.I would ideally do it on the pub first and then the sub. If you are planning to add domain check the forward and reverse look up on yr dns servers is configured correctly

Also if domain is make sure that utils network resolves correctly from pub sub else you might have DB replication issues

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