Jabber uses SIP/BFCP-based video through CUCM and/or VCS when using the Jabber Video [Movi] client. This has nothing to do with WebEx. All video functionality for WebEx is provided directly by the MeetingCenter client.
For customers with Cisco TelePresence installations there is a feature called WebEx One-Touch 2.0 which will allow a MCU to call into the WebEx cloud to establish two-way video streaming between users sharing video from WebEx and those on a TelePresence endpoint. The closest Jabber gets to this conversation is that they could dial into the MCU but I see no advantage to doing so since they could just as easily launch MeetingCenter on their PC and share video through that.
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