Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

Extension Mobility Fail over Problem?

Hi,

We have publisher and subscriber (CUCM v7.1.3) and on both servers is active extension mobility service.

When publisher is down extension mobility service doesn't work.

We configured two IP phone  services:

1) LOGIN#1   http://PUBLISHER_IP:8080/emapp/EMAppServlet?device=#DEVICENAME#

2) LOGIN#2    http://SUBSCRIBER_IP:8080/emapp/EMAppServlet?device=#DEVICENAME#

but, even if we have two services with different ip addresses, extension mobility doesn't work.

Also we tried with some external IP phone service such http://www.andtek.com/xml/xml-service.html?device=#DEVICENAME# (http://www.andtek.com/communications-products-freexml.html) and probem is the same, when pub is down EM doesn't work.

Is it posible that extension mobility does not work with fail over?

Best Regards,

Dusan

2 ACCEPTED SOLUTIONS

Accepted Solutions

Re: Extension Mobility Fail over Problem?

No, EM has redundancy in 7x.  That is a fundamental feature.  You should refer to the SRND for the architecture and exact requirements.  An excerpt is:

EM Redundancy

According to the EM architecture illustrated in Figure 24-4,  reads and writes to the Unified CM database are required. EM is a  user-facing feature, and database writes pertaining to EM can be  performed by subscriber nodes. Therefore, if the Unified CM publisher is  unavailable, EM logins and logouts are still possible.

From a redundancy perspective, the following three component levels of  redundancy must be considered for full EM resiliency:

Cisco CallManager Cisco IP Phone  Services

See IP  Phone Services Redundancy.

EM IP phone service

The EM IP phone service is the service that is selected by the user from  the IP phone services menu (or, alternatively, from a services line  button) in order to log in or log out of a phone. This phone service  points to the Cisco Extension Mobility Application service running on a  particular Unified CM node. As indicated previously, the Cisco EM  Application service provides the interface between the user (or phone)  and the Cisco Extension Mobility service. The EM IP phone service can  point to only a single IP address or host name.

Cisco Extension Mobility service

The Cisco Extension Mobility service is required for EM login and  logout. This service takes user credentials from the Cisco EM  Application service and then writes to and reads from the local  Unified CM database.

In order to provide redundancy for the Cisco CallManager Cisco IP Phone  Services (or URL Services) and the EM IP phone service components, Cisco  recommends using a Server Load Balancer (SLB) to serve as a front end  to process EM login and logout requests for multiple Unified CM nodes.  In this design, SLB functionality provides a virtual IP address or  DNS-resolvable hostname, as depicted in Figure 24-3,  which is used as the destination address for EM login and logout  requests from the IP phones. The SLB is configured to distribute these  EM requests to the real IP addresses of the subscriber nodes that have  the Cisco EM Application service enabled.

Most SLB devices, such as the Cisco Application Control Engine (ACE) or  the Cisco IOS SLB feature, can be configured to monitor the status of  multiple servers and automatically redirect requests during failure  events. By using the SLB virtual IP address (or DNS hostname) for the  URL Services and EM IP phone service, you can ensure that both  components are still available during a node failure and, therefore, EM  login and logouts will continue.


Note Multiple subscriber nodes in a  cluster can have the Cisco EM Application service enabled to provide  redundancy, but it supports only two subscriber nodes in a cluster  actively handling login/logout requests at a given time. The SLB device  configuration must support this design criteria.



Note Cisco does not recommend a  redundancy design using DNS records with multiple IP listings. With  multiple IP addresses returned to a DNS request, the phones must wait  for a timeout period before trying the next IP address in the list, and  in most cases this results in unacceptable delays to the end user. In  addition, this can result in more than two subscriber nodes with the  Cisco EM Application service enabled to handle login/logout requests,  which is not supported.


Because the Cisco Extension Mobility Application service subscribes to  cluster change notification, it maintains a list of all nodes in the  cluster with the Cisco Extension Mobility service activated. Therefore,  to provide redundancy for the Cisco Extension Mobility service  component, this service should be run on multiple nodes within the  cluster, and the Cisco Extension Mobility Application service will  provide automatic failover to any nodes running the Cisco Extension  Mobility service.

For the full SRND, go here:  http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/7x/cmapps.html#wp1043689

Hailey

Please rate helpful posts!

New Member

Re: Extension Mobility Fail over Problem?

Hello,

I believe your problem not EM service only, but with all configured service as you have Publisher IP Address configured in the URL Services parameter.

Are you sure that you can retrieve EM service when pressing on Service Button?

If not then you need to configure "IP Phone Services Redundancy" using server load balancing (SLB) as per SRND:

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/7x/uc7_0.html

Regards,

Ahmed Rizk

6 REPLIES

Re: Extension Mobility Fail over Problem?

No, EM has redundancy in 7x.  That is a fundamental feature.  You should refer to the SRND for the architecture and exact requirements.  An excerpt is:

EM Redundancy

According to the EM architecture illustrated in Figure 24-4,  reads and writes to the Unified CM database are required. EM is a  user-facing feature, and database writes pertaining to EM can be  performed by subscriber nodes. Therefore, if the Unified CM publisher is  unavailable, EM logins and logouts are still possible.

From a redundancy perspective, the following three component levels of  redundancy must be considered for full EM resiliency:

Cisco CallManager Cisco IP Phone  Services

See IP  Phone Services Redundancy.

EM IP phone service

The EM IP phone service is the service that is selected by the user from  the IP phone services menu (or, alternatively, from a services line  button) in order to log in or log out of a phone. This phone service  points to the Cisco Extension Mobility Application service running on a  particular Unified CM node. As indicated previously, the Cisco EM  Application service provides the interface between the user (or phone)  and the Cisco Extension Mobility service. The EM IP phone service can  point to only a single IP address or host name.

Cisco Extension Mobility service

The Cisco Extension Mobility service is required for EM login and  logout. This service takes user credentials from the Cisco EM  Application service and then writes to and reads from the local  Unified CM database.

In order to provide redundancy for the Cisco CallManager Cisco IP Phone  Services (or URL Services) and the EM IP phone service components, Cisco  recommends using a Server Load Balancer (SLB) to serve as a front end  to process EM login and logout requests for multiple Unified CM nodes.  In this design, SLB functionality provides a virtual IP address or  DNS-resolvable hostname, as depicted in Figure 24-3,  which is used as the destination address for EM login and logout  requests from the IP phones. The SLB is configured to distribute these  EM requests to the real IP addresses of the subscriber nodes that have  the Cisco EM Application service enabled.

Most SLB devices, such as the Cisco Application Control Engine (ACE) or  the Cisco IOS SLB feature, can be configured to monitor the status of  multiple servers and automatically redirect requests during failure  events. By using the SLB virtual IP address (or DNS hostname) for the  URL Services and EM IP phone service, you can ensure that both  components are still available during a node failure and, therefore, EM  login and logouts will continue.


Note Multiple subscriber nodes in a  cluster can have the Cisco EM Application service enabled to provide  redundancy, but it supports only two subscriber nodes in a cluster  actively handling login/logout requests at a given time. The SLB device  configuration must support this design criteria.



Note Cisco does not recommend a  redundancy design using DNS records with multiple IP listings. With  multiple IP addresses returned to a DNS request, the phones must wait  for a timeout period before trying the next IP address in the list, and  in most cases this results in unacceptable delays to the end user. In  addition, this can result in more than two subscriber nodes with the  Cisco EM Application service enabled to handle login/logout requests,  which is not supported.


Because the Cisco Extension Mobility Application service subscribes to  cluster change notification, it maintains a list of all nodes in the  cluster with the Cisco Extension Mobility service activated. Therefore,  to provide redundancy for the Cisco Extension Mobility service  component, this service should be run on multiple nodes within the  cluster, and the Cisco Extension Mobility Application service will  provide automatic failover to any nodes running the Cisco Extension  Mobility service.

For the full SRND, go here:  http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/7x/cmapps.html#wp1043689

Hailey

Please rate helpful posts!

New Member

Re: Extension Mobility Fail over Problem?

You was faster than me when replay to this

New Member

Re: Extension Mobility Fail over Problem?

Hello,

I believe your problem not EM service only, but with all configured service as you have Publisher IP Address configured in the URL Services parameter.

Are you sure that you can retrieve EM service when pressing on Service Button?

If not then you need to configure "IP Phone Services Redundancy" using server load balancing (SLB) as per SRND:

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/7x/uc7_0.html

Regards,

Ahmed Rizk

New Member

Re: Extension Mobility Fail over Problem?

Thanks for answers!

I have one more doubt about Services Provisioning (Internal, External URL) parameter.

Shout i leave default configuration Internal or set External URL.

"Internal

Phone Services are provisioned by the administrator, and the IP phone receives its list of configured

services from its configuration file that is downloaded through TFTP during the registration cycle.

The Services, Messages, and Directories URLs specified in the phone URL enterprise parameters

are not used"

This is not clear for me, if I set Service Provisioning: Internal,  how then I set URL for  Services, Messages, and Directories, if in SRND say that URL enterprise parameters are not used?

Thanks in advance!

Dusan

New Member

Re: Extension Mobility Fail over Problem?

Dear Dusan,

I believe the feature is called "Enhanced Service Provisioning". It basically allows an administrator to set a parameter which tells a phone to get service configurations either internally (using TFTP config file) or externally (using service URLs).

The configuration controlling how phones behave is controlled at a system-wide level with a new Enterprise Parameter called "Service Provisioning". This parameter can also be controlled at a device level via the "Common Phone Profile" setting on an IP phone. The default behavior is to use Internal Service Provisioning which means:

  • Phone Services are provisioned using IP Phone Service settings and delivered to the phone in the configuration file (TFTP)
  • Messages/Directories URL parameters are not used

When this parameter is set to use External Service Provisioning, the device will use the URL parameters as they would in pre-CUCM7x builds. So, Internal is the new method and External is the old method. You can also configure the "Service Provisioning" parameter to do both.

So Use SLB with External or Both in Sevice Provisioning configuration.

Attached where you can configure this "Common Phone Profile Configuration "

I hope this answer your question.

Regards,

Ahmed Rizk

New Member

Re: Extension Mobility Fail over Problem?

Thanx Ahmed!

Best Regards,

Dusan

2363
Views
5
Helpful
6
Replies