I'm looking for some guidance on doing named IM&P federation from Jabber to external organisations running Lync/SfB in an environment running CMS.
The current best practice method of federating video is to use Expressway in conjunction with CMS (as per this guide (https://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/expressway/config_guide/X8-9/CMS-Expressway-Deployment-Guide_X8-9-2.pdf) and that's fine, however the guide only briefly mentions Jabber/IM&P and chat.
The "old way" of using a dedicated Expressway-C in conjunction with the Microsoft interoperability seems to be a bit more fleshed out in the documentation, however the chat federation requires you to have SIP calling setup using this method and we are aiming to use CMS for video interoperability.
So my question is - if we are using CMS for video federation, can we still use CMS/Expressway for Jabber to Lync inter-domain chat/IM&P or do we still need the dedicated Expressway w/Microsoft interop key?
