Arggghh - These Rubbish new forum design - PLEASE CISCO SORT IT OUT. Just lost another half an hour as when hit the reply button after typing, you loose everything. Along with all the other problems (such as no spell check, no email subscription to the forum, RSS feeds hit and miss, poor performance, notification not showing properly, unable to see all of you own previous posts easily.. etc etc), what a pain.
Still, rant over and I not going to be beaten by this, so back to the post.. again
The VCS (Video Communication Server) server is an appliance that comes in two flavours - the VCS Expressway and VCS Control, commonly know as the VCS-E and VCS-C. They are often used together to provide a firewall traversal solution for traditional videoconferencing (H.323 and SIP) based endpoint that allow many devices inside an organisation the ability to talk to other devices in the outside world. However, they can also be used separately in some deployments.
A firewall traversal solution enable devices that use these chatty protocols (H.323 and SIP) to be able to communicate with like devices outside to corporate firewall, yet only mean that a small number of ports need to be opened or managed between a couple of devices. The protocol require a number of ports in order to operate, and multiple devices and calls may mean a large number of ports to many devices could be required to be open. Network admins general get the hump if they were asked to open whacking great holes in their firewall to enable such communication, and as such the VCS-C/E solution provides a neat way to enable this and keep the network admin happy. They do not replace a firewall, merely enable communication across it in an efficient manner.
To confuse matters, Cisco have decided to introduce the Expressway Solution which connects CUCM to a VCS-E (as mentioned above) with (as far as I understand it) a special licence. I don't know much about this solution as we don't use CUCM, although this seems to be Cisco's preferred communications technology going forward. It can register devices that use either SIP or SCCP (Skinny) protocols.
To further confuse things, Cisco in their infinite wisdom have two separate products called Jabber (!!!!) - one that works with CUCM, and the other called Jabber for Telepresence. I think the grand idea was to unify these clients however they are provisioned by two completely different technologies, one built by Cisco (CUCM), and the other build by Tandberg (whom Cisco bought), and I can;t see this happening any time soon. In fact Jabber for Telepresence has just had a new update release in the past few days.
In order to use Jabber with CUCM, you would obviously need CUCM. In order to use Jabber for Telepresence, you would probably need TMS (Telepresence Management Suite), although you can also purchase an Expressway starter pack (meant for small business I think) that is a VCS-E (as mentioned above) with another special licence enabling it too to provision Jabber for Telepresence clients.
I think you might be referring to Jabber with CUCM and the Expressway solution, although one thing to mention with all of this is that registration licences is not the same as call licences.
I expect this is as clear as mud, but unfortunately this is as straight forward as I think I can make it.
Good Luck
Chris
