Streaming media offers companies advantages when it comes to improving business processes and cutting communications costs. But there are also reasons why the vast majority of businesses do not yet stream video, audio, and graphics over their networks. High on that list of reasons is bandwidth. According to the HTRC Group, bandwidth is a serious consideration in terms of performance and user experience.
Engineers at West Virginia University are testing a variety of streaming video technologies on their network with the aim of deploying distance learning and other multimedia applications. The university uses 7.2Mb/s video streams to provide high-quality images.
But fast video streams don’t only support larger images and better resolution. They also place bigger demands on network resources. So, even with the university’s 622Mb/s asynchronous transfer mode connections, the technology has limitations. And as the HDTV (High Definition Television) video streaming standard begins to replace MPEG-1 and MPEG-4 (Motion Picture Experts Group) video streaming standards, the problem will get worse because compressed HDTV video streams run at 18Mb/s and uncompressed HDTV at 1.5Gb/s.
But few companies will be running even 7.2Mb/s streams, which actually exceed MPEG standards, across their networks. Most will stick to either the MPEG-1 standard, which supports video streams going over the network at speeds ranging from 900Kb/s to 1.5Mb/s, or MPEG-4, which specifies video streaming at 20Kb/s to 6Mb/s. Still, IT departments need to be smart about deploying streaming media at any level, so as to minimise bandwidth problems.
IT departments can confront the bandwidth issue in a number of other ways:
- Use multicast technology: companies can reduce the number of individual streams traversing their networks by using multicast technology. Instead of sending many streams to different users, multicast sends out a single stream and lets any user interested in receiving it tap in. Most LAN and WAN switches have multicast features built into them.
- Send streams in variable speeds: some video software and equipment, including products from Microsoft and RealNetworks Inc, allows users to encode streams at multiple bit rates. A multicast stream can be accessed at a high bit rate by PCs on a LAN, allowing the PCs to display full-screen, high-quality images. Remote users connected to a WAN would receive the same streamed media at a lower bit rate, which would produce high-quality, but not full-screen, images. Users dialing in via modem would receive the lowest-speed streams and the lowest quality of video, and still be able to hear the streamed audio.
- Institute quality of service: quality-of-service features built into networking equipment can help users control the amount of bandwidth allocated to a specific application. IT managers can set precise thresholds as to the amount of bandwidth used in a video application, thus helping to ensure that it doesn’t affect the performance of other applications on the network.
- Cache content: Cache video content on servers throughout the network, close to users accessing it. This minimises the traffic generated by centralised servers sending streams to outlying users.