At the end of 2006, there were an estimated 280 million broadband subscribers worldwide (ref. DSL Forum). This massive infrastructure has enabled the rapid creation of new markets such as VoIP, Digital Music Distribution, Online Gaming, Video Sharing, and IPTV, which in turn have led to a need for home networks that connect multiple users and a number of different technologies to the Internet. Home networks—originally architected simply to support web browsing via Internet connection sharing—are falling behind in their ability to support these new usage scenarios.
One of the biggest challenges faced by these networks is that different applications present different requirements. They vary not just in their overall bandwidth needs, but also in their relative tolerance for packet loss, delay and jitter while maintaining a high-quality user experience. When multiple applications with such disparate requirements run on the same network, problems can and will occur.
When we talk about "media" in this context, we are referring to network applications that require special treatment to guarantee a good user experience as network conditions vary. Table 1 shows a representative sample of a number of typical network applications, their bandwidth usage, and their relative tolerance for the variable loss and delay common in multi-application networks.
|Network Traffic||Bandwidth Required||Sensitivity to Delay or Packet Loss|
|Online games (Client)||10 ~30 Kbps||High|
|Online Games (Host)||10 ~ 30Kbps x # of players||High|
|Audio Chat||64K ~ 256Kbps||High|
|Audio + Video Chat||128K ~ 1Mbps||High|
|Voice over IP||110Kbps (G.711)||High|
|Internet Radio||80kbps ~ 256Kbps||Medium|
|Standard Definition Video||1Mbps ~ 10Mbps||High|
|High Definition Video||6Mbps ~ 25Mbps||High|
|Place Shifting (e.g.SlingBox )||Adaptive 100Kbps ~ 3Mbps||Medium|
|P2P File Transfers||Adapts to internet connection||Low|
|Bursts to internet connection||Low|
Table 1: Internet Application Requirements
Usage problems start cropping up, of course, when applications use more bandwidth than is available on the network, but problems also arise quickly when applications designed to move data from point A to B in the shortest amount of time (e-mail, file transfers, and so on) compete with those that are more sensitive to delay and packet loss ("media").
The challenge is creating a media-optimized network: How can these issues be minimized, or even eliminated entirely?