Despite the growing awareness of upload limits, cable marketing efforts in particular continue to focus on download speedsand for good reason. The cable companies coaxial pipelines can handle far more traffic than the phone companies copper wires, and they have also invested more in infrastructure upgrades over the last decade. Most cable providers could therefore easily deliver 6-megabit-per-second downloads right now, if they were willing to reduce the number of video-on-demand TV channels. In fact, many could even deliver up to 30 megabits per second per user, if customers were willing to pay for it.
Cable uploads, on the other hand, are severely constrained by current technology. It is unlikely that providers can cost-effectively deliver more than 384-kilobit-per-second uplinks to most subscribers. Fortunately, the latest cable modem standard boosts upstream bandwidth from todays 4.6 megabit per second (per neighborhood loop) up to 30 megabits per second. That means cable providers should be able to deliver upload rates of between 512 kilobits and 1.5 megabits per second per household.
The new cable standard does not require a major infrastructure overhaul, so deployment should begin in early 2005 and the technology should be in wide use by 2007. Because the new version also cleans up a lot of the noise on cable networks, thus improving VoIP quality, cable companies will have a powerful incentive to move quickly. Comcast, for example, recently announced plans to deliver VoIP to 95 percent of its installed base of 21 million TV subscribers by the end of 2005.
If phone companies want to remain viable broadband competitors with their DSL services, they’ll need to keep pace on upload speed. One sign that this may be happening is Verizon DSLs upgrade to a standard package offering 1.5-megabit-per-second downloads and 384-kilobit-per-second uploads, which represents a tripling of upload speed. This summer, meanwhile, Verizon will introduce 3-megabit-per-second downloads and 768-kilobit-per-second uploads; this souped-up connection should be available to the majority of existing customers, according to a Verizon spokesperson. Verizons announcement coincided with the news that it would enter the VoIP market this summer.
Long term, the phone companies must decide between an upgraded version of consumer DSL, which promises modest improvements, and a more far-reaching plan to offer a very high speed DSL that is capable of delivering video on demand. The first DSL version, which could become available as early as next year, offers download rates of up to 24 megabits per second (though in real-world deployments subscribes will probably get between 6 and 15 megabits per second, depending on their distance from the central office). The very-high-speed DSL service, which requires more infrastructure investment because it brings fiber drops closer to homes, delivers up to 50 megabits per second (realistically more like 20 to 30.) On June 22, SBC Communications announced it would invest between $4 billion and $6 billion on fiber upgrades for such a service over the next five years, with one-year trials starting this summer.
Beyond that, both phone and cable companies are planning for a long-term roll-out of fiber-to-the-premises, which would offer bandwidths in the hundreds of megabits per second. Due primarily to labor costs, however, widespread fiber deployment is probably at least a decade away.
So whats the role of upstream bandwidth in all these standards? The next DSL version offers an option for doubling upstream bandwidth, which could place real-world upstream performance at 1 to 1.5 megabits per second; the very-high-speed version would offer much more. Whether the telephone companies (or the cable companies) will actually deploy such bandwidth depends on public demand. As upload-intensive applications grow in popularity, the frustration heard from todays power users is likely to spread. Despite the TV-centric strategies of some broadband executives, after all, the Internet is not just a broadcast medium; its a communications medium.