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Walkthrough Wednesdays

Extension Mobility Cross Cluster (EMCC) Configuration Guide


Hello All,

This document describes the complete step by step configurations of  Extension Mobility Cross Cluster (EMCC). This is an extended version of normal Extension Mobility.


The Cisco Extension Mobility Cross Cluster feature allows a user of one CUCM Cluster (Home Cluster) to log into an IP Phone of another CUCM cluster (Visiting Cluster).


Let's get started with the configurations of EMCC!

EMCC Lab Setup:

Home Cluster CUCM IP CL1
Visiting Cluster CUCM IP CL2


Lab Topology for EMCC:Labsetup1.png


Concept of Extension Mobility Cross Cluster

When home cluster user logs in to visiting cluster phone, the remote phone gets register to home cluster.concept.png


Step 1: Service Activation

Login to the CL1 CUCM Service Ability Page > Tools > Service Activation >>

[✓] Cisco Call Manager

[✓] Cisco Tftp

[✓] Cisco Extension Mobility

[✓] Bulk Provisioning Service1.png


Step 2: Add Extension Mobility Cross Cluster Service

Just like Extension Mobility Service, we will have to create an IP Phone Service for EMCC.

Go to Device > Device Settings > Phone Services > Add new


Note: If we check the 'Enterprise Subscription', then the individual phones and device profile subscription not required.


Step 3: Device Profile Configuration

The device profile is a virtual profile which gets updated to the phone when we login via EM or EMCC. If you are running Extension Mobility on our network, this profiles likely to be there already. For the sake of lab, I'm adding a new Device Profile.


Go to Device > Device Settings > Device Profile > Add New

  • Device Profile Name: UDP_ABDUL_JASEEM_1001
  • Description: UDP_ABDUL_JASEEM_1001
  • Phone Button Template: Standard 7962G SCCP
  • Softkey Template: Standard User
  • Extension Mobility Cross Cluster CSS: EMCC_DEVICE_INTERNAL_CSS



Note: The 'Extension Mobility Cross Cluster CSS' gets used as 'Device CSS' of the remote phone during EMCC login.


Step 4: Subscribe EMCC Service to Device Profile

Select the Device Profile > Related Links > Subscriber/ Unsubscribe > Go4.png


Go ahead and Subscribe the Extension Mobility Cross Cluster service5.png


Step 5: Subscribe EMCC Service to Phone and Enable EM

Go to Device >  Phone > Related Links > Subscriber/ Unsubscribe > Go7.png


Also, check the 'Enable Extension Mobility' box on the device page.



Note: Using EMCC Service, we are able to login to any phones in the Home Cluster (Just like EM). Try logging in to any available phone in the CL1. This is to make sure the service URL is working fine.


Step 6: End User Configuration

Go to User Management > End User > Find.

Select the user and set a PIN (this PIN will be used to authenticate extension mobility login).9.png


Assign the Extension Mobility Profile to the user. Also, enable Extension Mobility Cross Clsuter check box.


Step 7: Customize Extension Mobility Service (Optional)

Go to System > Service Parameters > Select the Server where you have activated Extension Mobility Service & select service as Cisco Extension Mobility (Active)

Intra-Cluster Multiple Login Behaviour set to Auto Logout11.png


Step 8: Configure Visiting Cluster CL2

Perform the above Steps 1 to 7 in Visiting Cluster - CL2 as well.

Step 9: Setup SFTP For Certificate Management 

Install SolarWinds SFTP SCP Server on a Windows Machine. If you have already an SFTP Server running on your network, go ahead and use that. Please make sure this SFTP Server should be reachable from Home & Visiting Cluster.

After installing the software, launch the application.

File > Configure



Select 'Users' tab and 'New User'. Set a username and password as shown below. 


Apply Changes > OK


Go to the status bar of the application and Start the service.



Now, this is completed, in order to test the SFTP Server, use WinSCP or FileZilla and connect to the IP address of the machine where we have installed SFTP Server application.



I have used WinSCP software and I can connect successfully to the server.


Once this is ready, let's move to the Certificate Management section of EMCC configuration.


Step 10: Consolidate and Import Certificates 

Trust Certificates for both clusters must be signed by a common set of security tokens in order to EMCC feature to operate.


Login to OS Administration Page of Home Cluster (CL1) and Visiting cluster (CL2).

Navigate to Security > Bulk Certificate Management1.png


Provide the SFTP Server information (IP, user ID, Password) as shown below and Save6.png


Click Export from CL1 and CL2A1.png


Certificate Type: All and proceed with Export.A2.png


Now we have to Consolidate the certificates. (You need to perform the consolidate the certificate from any of the Cluster, no need to do it from both)9A.png






Now we have to Import the new consolidated certificate. Importing must be performed on both nodes.






Now we have successfully Imported the certificate to both clusters.!


Note: You can go to Security > Certificate Management to view the newly imported certificates. 


Step 11: EMCC Common Device Configuration

Common Device Configuration provides common settings for EMCC phones such as Softkey Template, MoH Audio Source, etc.


Go to Device > Device Settings > Common Device Configurations > Add New, then configure it as follows.1.png


Step 12: Add EMCC Template

EMCC Template plays the role of assigning Device Pool to visiting phones.

Read my another article which describes the EMCC Device Pool Selection Mechanism


Go to Bulk Administration > EMCC > EMCC Template > Add New2.png


Step 13: Update EMCC

We need to update EMCC devices with the EMCC Template.

Go to Bulk Administration > EMCC > Insert/Update EMCC

Select the Update EMCC Devices radio button and EMCC Template created in Step 12, then run the job.



Step 14: Insert EMCC

Now we are going to insert the EMCC Virtual Devices. For this example, I'm adding 5 EMCC Devices.

Go to Bulk Administration > EMCC > Insert/Update EMCC

Select the Insert EMCC Devices radio button and enter the number of EMCC Devices, then run the BAT job.4.png


Step 15: Configure Visiting Cluster CL2

Perform the Steps 11 - 14 in Visiting Cluster - CL2

Step 16: Configure Cluster ID on both Clusters

This parameter provides a unique identifier to the cluster.

Go to System > Enterprise Parameters

Set cluster ID for both Home and Visiting clusters.




Step 17: Add Geolocation Filter

Home Cluster will consider the Geolocation of the Visiting phone using the Geolocation filter specified in the EMCC Feature Configuration. Then match the Geolocation information from the home cluster to assign specific device pool.


When this parameter is set to None, EMCC will not function correctly; phones that attempt to login but cannot be assigned to a roaming device pool will fail to log in.


Note: Since I planned to put all the visiting phones in dedicated EMCC Device Pool (Based on the EMCC Template), I haven't configured any Geolocation for the visiting phone. But Geolocation filter is mandatory to configure EMCC


Read my another article which describes the EMCC Device Pool Selection Mechanism


Go to System > Geolocation Filter > Add New, configure it as follows.6.png

Step 18: EMCC Feature Configuration

These are the set of configurations used by EMCC.


Go to Advanced Services > EMCC > EMCC Feature Configuration


  • Default TFTP Server for EMCC Login Device: [Select TFTP Server]

This should be used by the phones logging in to EMCC from a remote cluster.

  • EMCC Geo Location Filter: [Select the filter created in Step 17]
  • Default Server For Remote Cluster Update: [Select a node where EM Service running]

Choose the default server name or IP address of the primary Cisco Unified CM server in this local cluster that has the Cisco Extension Mobility service activated. The remote cluster will access this server to get information about this local cluster.




Step 19: EMCC SIP Trunk

This is used Visiting Cluster PSTN Access for emergency dialling.

Go to Device > Trunk > Add New >1.png


> Next 

configure the trunk parameters as given below,2.png




Please reset the SIP Trunk after saving.

Note: EMCC SIP Trunk doesn't have any destination IP Address!

Step 20: EMCC Intercluster Service Profile

We have to enable EMCC feature in this step. Also, specify the SIP trunk for PSTN access.


Advanced Features > EMCC > Inter Cluster Service Profile > Add new4.png


You can click Validate to see the status.5.png


Step 21: Add Remote Cluster

At this step, we specify the remote cluster where home cluster contacts for EMCC login.


Advanced Features > Cluster View > Add New6.png


Step 22: Configure Visiting Cluster CL2

Perform Steps 17 - 21 on Visiting Cluster CL2

Step 23: Update EMCC Remote Cluster on both

Make sure home cluster and visiting cluster discover each other.


Advanced Features > Cluster View > Select the Remote Cluster

Perform the same on CL2



Great! We have done the EMCC Configurations successfully! Its time to test and understand the EMCC Registration.

Verify EMCC Login 

Select any of the phones in Visiting Cluster CL2.

  • Press Service Button and select "Extension Mobility Cross Cluster" service. Enter the User ID and Password of the Home Cluster user.
  • Enter the User ID and Password of the Home Cluster user.


  • I have a home cluster user 'abdul.jaseem' trying to login to remote cluster phone which is highlighted below.



  • The device on the Visiting Cluster CL2 will unregister and the same device remotely registers with Home Cluster CL1.
  • Go to home cluster Device > Phones > Remotely Logged in Devices



  • You can see that the visiting cluster phone unregister from CL2 and register to CL13.png


That all about Extension Mobility Cross Cluster Configuration. I will be covering detailed information about the Call Routing In EMCC Login in my next article.


You find more information about EMCC Call Routing and EMCC Error codes for troubleshooting in the below links.

Link 1: More on EMCC Call Routing

Link 2: EMCC Error Codes 


Please share your thoughts here and feel free to ask doubts. 



Can a jabber for windows client control users phone profile if it exists in the visiting cluster?




Nice, brief explanation.




Hi there,

We have 2 clusters with multiple country/region presence in each. For example, we have a cluster that supports sites in the US and Australia (call it CL1), and another that Supports EMEA region and Bangalore (call it CL2).  For this scenario, would we need to configure an EMCC SIP trunk for US to CL2, and another for Australia to CL2 so that the trunks are able to have the correct regions Device Pools (and SLRG's) configured, as per step 19?  


Thanks for the above configuration guide, its been very helpful.  

Regards, Sharon



Cisco Employee

Nice detailed explanation Abdul. Thanks.