MBONE - Page 12

This is by no means a new idea - it's the principle behind IP multicasting, which was developed back in the early 90s, when the very idea of audio or video over the Internet was considered laughable. A set of experiments in live audio/video multicasting by the IETF back in those days resulted in the MBONE (Multicast Backbone), a virtual network that leverages the power of internal end-user networks to get around the bandwidth limitations of the Internet.

The MBONE as such has faded from the headlines. It never became very well-known outside the academic community, and newer technologies such as streaming and better compression algorithms have passed it by. However, the basic concept behind it, called multicasting, is a powerful one, and is one of the building blocks of today's streaming media networks.

Typically, an Internet user requests a file from a server, which then delivers the file to that individual user. If there are a large number of users in the same geographic area, this is obviously very inefficient, especially if they are all viewing the same sequential program. In fact, if there is a sudden upsurge in the number of viewers, as for a live event, the flood of individual connections may be enough to clog up the whole network.

With multicasting, however, the data travels from the server directly to multiple network nodes, which then distribute it to the end users. Under the MBONE model, these nodes were typically Ethernet networks at college campuses and the like, with the users logged on to the network. However, the same concept can be used to send a high-bandwidth signal to local ISPs around the country. If a perfect, high-bandwidth signal can be delivered directly to the backbone of a user's local ISP, the chances of a good-quality signal reaching the user are high, especially if the user is connected through a cable or DSL network.

In a sense, this idea is the reverse of the one behind the MBONE. The MBONE depended on a high-quality network at the user end (campus Ethernet), while the newer approach depends on a high- quality network between content provider and local network, leaving the "last mile" as the only weak link in the signal chain. Naturally, serious users who enjoy a high-bandwidth link to their ISP can also enjoy top-quality A/V through an almost seamless high-bandwidth connection to the streaming servers.

Streaming Media Networks

One company that has put this idea elegantly into practice is iBEAM. IBEAM has built a nationwide network of media serving systems that claims to deliver superior streaming media performance. Access to their network can be purchased through the usual bewildering array of "solutions," as well as through various partners, and is available on a continuous, on-demand, or one-time basis.

The iBEAM network uses satellite transmission to feed streaming media directly to over 150 local ISPs, as well as some of the large access networks such as Excite@Home, AOL, and BellSouth. Each of these access points hosts one of iBEAM's proprietary MaxCaster(tm) media serving systems, which consists of a satellite dish downlink, a fault-tolerant, enterprise-class Dell server, and an Extreme Networks Layer-2 switch. The idea is to serve the streams from as close to the end user as possible, or as iBEAM puts it, to push the servers closer to the "edge" of the Internet.

IBEAM's Streaming Media Network (SMN) also includes a couple of massive central server farms on each coast, located at major Internet backbone providers. The network features intelligent load balancing, which automatically routes traffic to the nearest access point.

Another Streaming Media Network provider is Akamai. Like iBEAM, they offer to deliver content from closer to the "edge" of the Internet for big gains in performance and reliability. EdgeAdvantage and EdgeSuite are the names of a couple of items on their menu. Akamai also offers other media services including live Webcasts, video production, encoding, and hosting.

Servecast is a SMN based in Europe, billing itself as "Europe's leading business-to- business provider of outsourced Internet broadcasting services." Just as iBEAM has done in the US, Servecast has built a load- balanced, "edge delivery" network.

Yet another SMN is Ituner, which offers a worldwide network. They also offer an interesting piece of hardware called the MediaBox, a small network appliance that incorporates audio/video encoding and an Internet server. Simply plug audio or video into the RCA jacks on the front, and a (10 or 100) Ethernet connection into the back, and away you go. The MediaBox can encode live, in MP3, RealAudio and RealVideo formats, all at once, or it can serve on-demand content in MP3, RealAudio and RealVideo as well as QuickTime. It runs on the Linux OS.

Three Steps to Online Broadcasting - Page 11
Next Wave of the Web
Hosting Services for Streaming Media - Page 13