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New Member

Extension Mobility will stop running when Pub goes down

Read another post and has mentioned that Extension Mobility will stop running when Publisher goes down. Is that the case? Thought when Publisher goes down, all the CCM Admin change will be out-of-syn, but EM should be working without any problem. Thanks in advance. Any urls related to this will be helpful?

6 REPLIES
Super Bronze

Re: Extension Mobility will stop running when Pub goes down

Hi

If the publisher is down, EM stops working - it basically makes changes to the CM config DB, which is only writeable on the publisher.

See this excerpt from the CallManager SRND (http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_implementation_design_guide_chapter09186a0080447510.html#wp10458460):

Cisco CallManager Publisher

The publisher replicates a read-only copy of the master database to all other servers in the cluster. If changes are made in the publisher's master database during a period when another server in the cluster is unreachable, the publisher will replicate the updated database when communications are re-established. During any period when the publisher is unreachable or offline, no changes can be made to the configuration database. All subscriber databases are read-only and may not be modified. Most normal operations of the cluster will not be affected during this period, including the following:

?Call processing

?Failover

?Installation registration of previously configured devices

There are some features and functions that require access to the master database on the publisher because they make modifications to records and therefore need write access. The publisher is the only server in a Cisco CallManager cluster that has a read and write configuration database. The main features and functions that require access to the publisher for write access include:

?Configuration additions, changes, and deletions

?Extension Mobility

?User speed dials

?Cisco CallManager User page options requiring the database

?Cisco CallManager software upgrades

?Call Forward All changes

?Message Waiting Indicator (MWI) state

Other services or applications might also be affected, and their ability to function without the publisher should be verified when deployed.

Regards

Aaron

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Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!
Hall of Fame Super Red

Re: Extension Mobility will stop running when Pub goes down

Hi Tom,

Here is some information that confirms your suspicion. Have a look;

Intracluster Communication

Two primary types of communication occur within a Cisco CallManager cluster. The first type of intracluster communication provides a mechanism for distributing the database that contains all the device configuration information. When you make configuration changes in Cisco CallManager Administration, the publisher server initially stores those changes in its local database. The publisher then sends the new data to all the subscriber servers in the cluster, so they can update their local copies of the database. This mechanism ensures that the configuration database remains consistent across all servers in the cluster. The mechanism also provides database redundancy because the subscriber servers can continue to operate from their local copies of the database even if the publisher becomes unavailable for any reason. In the case of an unavailable publisher, you cannot update subscriber copies of the database. Therefore, when the publisher is unavailable, phone updates cannot occur, call forwarding cannot be modified, message-waiting state information will be lost, and ***Cisco CallManager Extension Mobility stops functioning.***

The second type of intracluster communication involves the propagation and replication of run-time data such as registration of IP phones, gateways, and digital signal processor (DSP) resources. All servers in the cluster share this run-time data and thus ensure optimum routing of calls between members of the cluster and associated gateways.

From this doc;

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_administration_guide_chapter09186a00803eda7f.html#wp1021999

Hope this helps!

Rob

Please remember to rate helpful posts........

New Member

Re: Extension Mobility will stop running when Pub goes down

Thank you for all of your help.

We are running CCM v4.1(3) and all users are using EM. Every monring when they are back to the office, they login to their EM profiles. Let's say during the day the Pub goes off, since most of the users are already login to their EM profiles, thus I assume their phones are still functioning. But other users will not be able to login EM during the Pub goes offline. Has anyone experience this before? Is that the case? Thank you in advance.

Super Bronze

Re: Extension Mobility will stop running when Pub goes down

Hi - Yes, that's the way it works.

Aaron

Please rate helpful posts...

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!
New Member

Re: Extension Mobility will stop running when Pub goes down

Thank you for the advice.

Our Pub is running CCM 4.1(3) with MCS-7845-H1-IPC1 with four 72GB SCSI HDD. I believe they are running with RAID 1. We've also bought the exact same hardware server for the COLD STANBDY purpose. In this case if the Pub HDD is crashed, I assume the quickest way to recover is to unplug the backup HDD and plug it into the COLD STANDY CCM server. What is the quickest and proper way to bring up the Pub online? Thanks again.

Super Bronze

Re: Extension Mobility will stop running when Pub goes down

Hi

If one of your HDD dies, you won't lose service or data as the RAID controller will keep the system running on the other disk in the array.

If you lose two HDDs in one RAID1 array, you lose your data. So have a backup you can rebuild and restore from.

What you're talking about is if the server itself dies... You can then take disks out of the dead server, place them in the cold standby, and make sure you select 'recovery mode' when prompted or you will wipe the array info from the disks!

Basically the HP RAID controllers store raid config on the controller and on each HDD. This means the controller can be swapped or the disks moved to another controller without destroying the RAID config.

You can test this by:

Pulling one disk from each RAID1 array (use the HP Array Config util in Windows to identify which drives are which array) noting which slot the disks come from.

Putting the disks into the same slots on the cold box

Selecting recovery mode when the server is booted.

If it works, you have a method to recover the server by... If not, put the disks back where they were (when the hot standby IS running so that you know the disks you are putting back will be overwritten!) and post back what happened...

I've done this lots of times on CallManager as well as countless other types of servers on HP kit.

Regards

Aaron

Please rate helpful posts.

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!
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