It’s great to see the major desktop appliance (thin client) vendors, including HP/Neoware and Wyse, rallying around the Citrix Multimedia Virtualization Initiative. A notable example of how our ecosystem partners add value is TCX Multimedia 2.0 from Wyse, a streaming media solution (think training videos and corporate broadcasts accessed in an ICA session). At iForum 07 – The App Delivery Expo – Wyse and Citrix announced that TCX Multimedia 2.0 has achieved Citrix Ready status (see the press release from Wyse).

TCX Multimedia provides an intriguing complement to SpeedScreen Multimedia Acceleration (one of several technologies explained in Brian Madden’s video on SpeedScreen). As with SpeedScreen Multimedia Acceleration, the media player runs on Presentation Server but the multimedia (video and audio) data stream is decoded and played locally on the client with a virtual channel being used for start/pause/stop and other controls. And both technologies deliver a great user experience by leveraging the processing power of the client device while maintaining the advantages of a centralized application delivery model. The key difference with TCX Multimedia is that the multimedia stream can be delivered directly to the user desktop appliance from a local media server instead of going through the data center. TCX Multimedia attempts to establish a direct path from the source to the client. This isn’t always possible and the solution will fall back to obtaining the media stream through ICA when necessary to traverse firewalls, but when it is possible it has the benefit of consuming less network bandwidth and reducing the load on Presentation Server, which is good for performance and scalability (number of concurrent users per server). The beauty of the TCX Multimedia software is that it can intelligently and dynamically decide when to redirect the multimedia stream.

Another noteworthy feature of TCX Multimedia is its multicast support (limited to MPEG-1). Multicast provides a very efficient way of delivering the same multimedia stream to many users at the same time. Suppose your CEO is addressing the troops for a quarterly state-of-the-business update. Potentially a large number of people want to watch the videocast simultaneously, in real time. With multicasting, each individual packet can be sent to many endpoints simultaneously, consuming much less network bandwidth than if the media stream had to be replicated for every user. And multicast uses UDP/RTP. UDP (User Datagram Protocol) is better suited to live videocasts than TCP/IP because it is a “best efforts” protocol that doesn’t get stuck doing retransmissions if some packets are lost; timeliness is more important than completeness. RTP (Real-Time Protocol) adds timestamps and other controls to help keep the audio and video in sync.

TCX Multimedia supports a broad set of media formats: MPEG-1, MPEG-2, MPEG-4 part 2, WMV (Windows Media Video), WMA (Windows Media Audio), AC-3 (Dolby Digital) and MP3. The notable omission at this time is Adobe Flash.

What next? Wyse notes that support for Linux is “coming soon”.

Derek Thorslund
Product Strategist, Multimedia Virtualization