Opportunity Knocks for Multimedia

I'm not an expert on media or sociology, but when I travel to new places I find I always turn on the television or radio. It seems that you can quickly find out quite a bit about a new place by simply listening to its local radio stations or watching the television. That's neither a radical nor profound observation, but the situation for media outlets is changing. Local radio and television are turning to a new form of broadcasting that overcomes the limitations of antennae and distance: Internet simulcasting.

Radio stations around the world are taking their programming and making it available on the Internet. This means that, if you are so inclined, you can listen to the BBC from the comfort of your office desk or a broadcast of Australian Rules Football from a suitably equipped machine at home. In fact, more than 1,550 stations from more than 100 countries pump out music, news, and more over the Internet. Far more than just a "gee whiz" technology, the emergence of broadcast media on the Internet may have repercussions inside the corporation.

The last four Internet conferences I've attended have been broadcast over the Internet using this technology. This means that if I wasn't able to attend because of scheduling or finances, I could at least participate remotely. A recent conference on domain names was held in Singapore. I couldn't go, but I did participate: I "tuned in" over the Internet.

If you can make Internet radio and television work efficiently, it's not a huge leap to imagine corporate, intranet-based radio or television stations that company staff can "tune into" to find the latest in company news, training and information. Best of all, corporations could do this without the financial and regulatory hassles of setting up a real station.

The technology that is making this possible is called streaming media. The idea is actually quite simple. A radio station simply takes its audio feed and digitizes it using a well-known technology called a "codec." Once in digital form, the radio feed can then be broken into packets and shipped over the Internet. At the client's desktop the packets are collected, reassembled and converted back into audio format using special client software.

It's possible to store media and then forward it to a client at a later time, but it's also possible to take the audio or video information and convert it on the fly. Either way, the packets flow from the server to the client's "player," providing a continuous stream of media. To avoid the hiccups that packet loss or delay causes, the stream is buffered at the client's end. When that stream is interrupted, as it often is on the "best effort" service of the Internet, the result is scrambled video or audio that sounds as if it's coming from a turn-of-the-century gramophone.

The current generation of multimedia technologies avoids some of these performance problems -- but at a cost. For example, streaming media still uses the Internet's traditional unicast approach. If you and I are listening to the same broadcast of a Dutch soccer match, the server provides a stream to me and a completely separate feed to your computer. Multiplied over thousands of connections, this results in a tremendous waste of bandwidth. Streaming media, to be a long-term success, must be combined with a reliable multicast infrastructure on the Internet to avoid congestion and bandwidth problems.

The client software uses another trick to ensure reasonable performance: It opens multiple TCP connections between the server and client, effectively providing multiple pipelines for the streaming packets. Unfortunately, the result can be congestion in an organization's or provider's routers when the streaming media aggressively consumes bandwidth and doesn't properly back off in the event of congestion.

These aren't just niggling concerns. The issue of congestion is so important that some Internet engineers have proposed packet-dropping schemes that would effectively force streaming media to fairly share bandwidth with other applications. Without effective multicast, some network managers are blocking streaming media from coming from outside their networks.

Still, the promise of inexpensive streaming media is obvious. Whether it's a radio station from the other side of the country, a video feed from a conference you missed, or your own corporate news channel, streaming media on the Internet is in our future. But before you log into Radio Eireann to get your daily dose of Irish culture, let's pressure the streaming media vendors to help build a multicast infrastructure and products that fairly and equitably use bandwidth. --Mark McFadden is a consultant and is communications director for the Commercial Internet eXchange (Washington). Contact him at mcfadden@cix.org.