The Cable Modem Revolution Essay Research Paper

The Cable Modem Revolution Essay, Research Paper The Cable Modem Revolution Cable modems are the latest tools used for high-speed Internet access. These modems connect to the Internet via coaxial cable lines rather than telephone lines like conventional modems. By making use of the larger coaxial cables, cable modems are able to transfer much more data than anything in the past. These new modems can connect up to 180 times faster than the fastest analog telephone modems available today. In other words, a file that takes fifteen minutes to download using a 56k modem only takes about five seconds on a cable modem. Currently, cable modems are capable of data transfer rates of up to 40 Megabits per second (Mbps). Although rated as so, most of the cable modems today can

realistically transfer around 10Mbps. Like regular telephone modems, cable modems have to modulate and demodulate the stream of data from different computers at different locations. The similarity with analog modems ends there, however. Cable modems also incorporate a tuner (to separate the data signal from the rest of the broadcast stream); parts from network adapters, bridges, and routers (to connect to multiple computers); network-management software agents (so that the cable company can control and monitor its operations); and encryption devices (so your data isn t intercepted or sent somewhere else by mistake). In order to use a cable modem, certain hardware is needed. First of all, you need a fast computer. A Power PC or Pentium processor with sixteen Megabytes of RAM would

be recommended as a minimum. Next, you need to have a network interface card (NIC) installed in the computer. The most popular NIC used today is an Ethernet card (10baseT). Finally you need the cable modem itself and wires to hook everything up. The physical connection is pretty straightforward but then you have to configure you computer with standard TCP/IP software. Once connected, the computer is hooked up directly to the Internet. There are no phone numbers to dial and no limitations to serial-port throughput as is the case with ISDN modems. Although cable modems use the same wires as your cable television, they operate at a separate frequency from that of cable television channels. By doing so, cable modems should operate without interfering with television reception. But

pulling this off requires careful integration because of the way cable systems are currently set up. Most cable systems are used to sending signals in only one direction. Internet access, obviously, is two-way: every mouse click, every command and keystroke must travel back upstream. In order to become interactive, cable operators must allocate a spectrum on the cable for upstream signals so you can send data from the PC back to the Internet. Typically, the upstream signal is transmitted via a low frequency band that hasn t previously carried a TV channel. This low frequency band, however, is noisy due to the interference caused by such devices as CB radios, household appliances, and lights, which must be filtered out somewhere between the nearest distribution junction and the

cable recipient. Another drawback is that all homes or offices connected to the same junction share this one transmission channel. And as is the case with an Ethernet network, too many nodes competing for bandwidth can slow network performance. If your neighbors do lots of downloads, your throughput will suffer unless the cable operator provides additional capacity or extra routers and channels. Cable companies will also have to modify their cable amplifiers to separate the upstream and downstream signals. In some regions, they ll end up replacing most amplifiers and putting lines closer to each home. Finally, cable operators will have to set up a community-wide Internet point of presence (POP) to serve all the networks associated with a particular distribution junction. This