Never to be left out of a market, Cisco Systems bought digital video vendor PixStream in December 2000 to add to its broadcast video line. Cisco changed only the logo and name of the PixStream VDS2000. Of the units we tested, the VN 2900 was the worst performer. It has some advanced features, though, and offers the largest number of encoders and decoders in one chassis.

The VN 2900 handled reordered and duplicated packets rather poorly and presented pixel jitter and dropout. On the latency side, audio and video both broke down at more than 5 ms of deviation. Oddly, the VN 2900 performed better when we mistakenly tested it with uniform latency deviation rather than with the Gaussian distribution we used for the other products.

Even with the poor test results, the VN 2900 has several redeeming qualities. For starters, it has good port density and allows any combination of up to 10 encoders or decoders to be placed in the unit. Cisco offers two decoder cards -- 4:2:0 and 4:2:2 (see "Digital Video: How IT Works"). None of the other products offers 4:2:2 decoding, and Cisco's doing so seems strange, as it does not offer a 4:2:2 encoder. The decoder and encoders have the normal unbalanced left and right audio connections along with composite and S-Video.

On the network side, the VN 2900 has the widest range of options. Video can be transmitted over 10/100 Ethernet and ATM. Cisco offers ATM DS-3 and OC-3 modules for the VN 2900. Although GDC's MAC 500 also provides ATM and Ethernet options, only Cisco allows interface modules to be loaded into the chassis to broadcast over ATM and Ethernet simultaneously. (GDC says it expects to offer a similar capability later this summer.) The controller card has a built-in Ethernet interface, which also can be used to transmit or receive video.

To configure the VN 2900, we needed to load the unit's VDSmanager software on a Microsoft Windows-based computer. VDSmanager provides a graphical interface to configure each of the cards and streams of video and audio. Although the software takes some getting used to, it works well enough for us to hope Cisco will leave it alone and not try to incorporate Cisco IOS into the VN 2900.

VDSmanager offers a click-and-connect interface for creating video streams for distribution. Connection entails clicking on the two end points you desire and selecting "Connect." One end point is an Ethernet or ATM interface card; the other, an encoder or decoder. You also can connect an encoder directly to a decoder without the signal leaving the chassis.

Graphically, VDSmanager is a great way to see your connections, which appear as lines between the interfaces and encoders or decoders. Multiple streams can be created on each network interface. One or more encoded video sources can then be connected to several streams on the network interface.

On the decode side, Cisco provided a feature we really enjoyed, as it made testing verification a little easier. The decoders have several options for displaying additional information -- including image resolution, bandwidth used and network delay -- along with the output video. We could have even loaded our Network Computing logo and displayed it in the corner of our video -- just as many TV stations do during their broadcasts. This is perfect for customers that want to ensure that hard copies of transmitted video retain the corporate copyright.

Although the VN 2900 has options for automatically detecting and adapting to network delay on the decoder module, ours was unable to keep up with our tests because the delay was constantly changing. The VN 2900 can handle the greatest number of video sources in one chassis and offers multiple network connections. If Cisco can improve the software to handle bad networks, it'll have a real performer to offer to customers.

VN 2900 Video Networking System, starts at $15,000. Cisco Systems, (408) 526-4000, (800) 326-1941; fax (408) 526-4100. www.cisco.com