Understanding Jabber: Part 3- Extend & Connect

Being the third part in this series I thought I would take a look at one of the features that quite frankly is a little misunderstood. Jabber Extend and Connect seems to get confused with Unified Mobility quite often. Even though it has some similarities it is a very different feature.

Extend & Connect

Extend and Connect was introduced in Cisco Unified Communications Manager (CUCM) 9.0. It is a unique feature in that it takes the concept of controlling a phone and allows you to take advantage of any phone in conjunction with your Unified Communications application. In this case it happens to be Jabber. What's unique to Extend and Connect is that it does not require the phone to be on any particular system but it can be any phone on any system. A home phone or a cell phone are good examples of devices that typically are not part of a CUCM deployment that can be used by Extend and Connect. The Jabber user has the ability to set the number to any routable number that Communications Manager (CUCM) is configured for. What I really like about this is the limited amount of integration that is required between Communications Manager and the legacy or other system you are using the device on. This is because this is being mostly contained within the Cisco UC environment and the only thing required to an external system is typical gateway/trunk connectivity.

The Extend and Connect feature for Unified CM provides the following UC features:

  • Receive incoming enterprise calls
  • Make Call
  • Disconnect
  • Hold and Retrieve
  • Redirect and Forward
  • Call Forward All
  • Do Not Disturb
  • Play DTMF (out-of-band)
  • Consult Transfer, Conference
  • Add, edit, and delete Remote Destinations
  • Set Remote Destination as Active or Inactive

How does it work?

Below is a diagram overview of Jabber controlling an external endpoint. In this case it can be either the home phone or a third party PBX phone. CUCM has a CTI remote device based on the users Enterprise DN configured in its database. The Remote device is associated with the user Jabber device through the user account. Now I don’t want to bore everyone with a bunch of configuration mumbo-jumbo, the important thing to remember is that through CTI integration with Jabber we can basically control any device we want.


Below is a screenshot of what the user would see.


In this case I have created a fake number in the CTI Remote destination profile just to show how it functions. If I had entered the number though Jabber, CUCM will check that the number is routable. This ensures that the user doesn’t enter an incorrect number that is never going to work. In the example below I entered a non-routable number and Extend and Connect shows up with the red X to show the error.


Difference Between Unified Mobility and Extend & Connect

To put this simply Unified Mobility is really designed for redirecting calls destined to your enterprise phone number to other personal devices. There is no ability to provide any call control of this other device (transfer, hold etc). You can however retrieve a call back on your enterprise phone once you have ended the call from your personal device but the whole idea is more akin to single number reach.Ring your enterprise number and a whole bunch of other devices ring with it and you can retrieve the call basically anywhere you desire.

Extend and connect on the other hand gives the user  control over any endpoint and allows inbound calls to their enterprise number to ring this CTI controlled device. It has some similarities to Unified Mobility in that respect but that is where it ends. This basically now allows a user to use the external phone devices as if it were a enterprise device. of course having a UC application like Jabber to work with the feature is a must and this is how CTI control is maintained.

Extend & Connect Use Cases

The most obvious one is a UC migration. Taking the latest Cisco has to offer and layering it over a legacy PBX install. This enables being able to gradually migrate phones over time is a great option. It also opens the door to replacing phones altogether but allowing users to get comfortable with softphone phone services first but still have the ability to take control of a hard phone if they want to.

Next use case is the remote user that may not have good IP connectivity and using a more traditional phone service might work better. A hotel is a good example or if you are a teleworker and landline based services are just more reliable. Being able to direct and manage calls to any phone is what gives Extend and Connect it advantage versus other similar features on other platforms.

Lync Remote Call Control versus Jabber Extend & Connect

I thought this was an interesting comparison of two similar features on two different platforms. The actual original intent of RCC in Lync was similar to that of Extend and Connect but the features of RCC have slowly been depreciated over the years as Microsoft looks to have a more robust voice feature set. Setting this aside the concept of the UC overlay on top of a legacy PBX made a compelling use case and still does as some companies look to more slowly adopt UC features. Although Extend and Connect takes this beyond just a UC overlay RCC’s sole purpose was the overlay as it required SIP/CSTA integration. This meant that to take advantage of RCC you required an on-premise PBX that had the ability to do SIP/CSTA or some sort of CSTA gateway that could do the interoperability. In either case you are limited to on-premise PBX’s with RCC.

RCC also limits a user between switching from using the client as a softphone or remote controlling a another desk set on the fly. Once a user is set for RCC there is no switching to softphone mode unless an administrator makes a change for the user. This used to be allowed when Microsoft had interoperability with Nortel PBX’s but has since been removed. Microsoft clearly designed RCC for migration from legacy PBX to Lync softphones and not as a feature extension once the migration is complete.

Extend and Connect on the other hand isn't bound by the CSTA constraint. By using CTI along with Jabber and substituting numbers within CUCM, other than normal PSTN connectivity nothing else is required to make Extend and Connect function. Admittedly the manner in which some features function is a little different compared to RCC mainly because there is no direct integration ties beyond normal voice connectivity but I see this as a positive as it makes setting it up easier.

Extend and Connect also doesn’t limit the users options to switch the client to use other Jabber features. This means a user has three options with Jabber as it relates to telephony

    1. Jabber as a softphone,
    2. Jabber with Extend and Connect or
    3. Jabber Desktop phone control of a CUCM registered IP Phone or TelePresence endpoint.

This gives an organizations lots of options for a migration from a legacy PBX. It also enables a number of options for remote workers.

Hope everyone is enjoying the series.




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