Copyr ight © CRC Pr ess LLC
by Abhijit S. Pandya; Ercan Sen CRC Press, CRC Press LLC
ISBN: 0849331390 Pub Date: 110198
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IV. Cable-TV Networks
Prior to the passage of the Telecom Act’96 in February 1996 by the U.S. Congress, cable-TV networks were limited to providing TV service to the general public. One of the key objectives of the Telecom Act’96 was to
break the monopoly in local telephone service provided by the RBOCs Regional Bell Operating Companies and other telephone operators in a particular telephone service area. There are currently three access solutions
available to provide competitive telephone service. These are wireless network, cable-TV network, and unbundling of PSTN access through telephone wire connection.
Although the cable-TV network operators were very enthusiastic about getting into telephone service as a new business opportunity following the passage of Telecom Act’96, their initial enthusiasm has been dampened by
the realization that it will require a significant amount of investment to offer traditional telephony service over a cable-TV network and be very difficult to offer cheaper telephone service than the PSTN operators,
particularly in the U.S.
However, these cable-TV operators soon realized that they could offer high speed Internet access, instead of telephony service, to cable-TV subscribers using the large amount of bandwidth available in their cable-TV
networks. At the present time, cable-TV network operators are already offering fast Internet access while telephone operators are still struggling with the type of technology to use such as ADSL to provide fast
Internet access to their subscribers. Eventually, as VOI and VTOA become mature technologies and widely used, then it will be possible for cable-TV operators to provide very cost-effective telephony service to their
customers.
We next look at how ATM technology can be used in cable-TV networks to provide fast Internet access. The cable-TV networks are currently capable of providing 10 to 30Mbps down-link capacity to the cable user.
However, the up-link from cable user to cable ISP is still problematic. In most cases, the up-link requires a modem connection over PSTN to cable ISP with low bandwidth capacity. This situation still maintains the
monopoly of PSTN operators. Fortunately the latest cable installations will allow up-link capability from 750Kbps to 1.5Mbps range over the same cable infrastructure. A typical cable networking infrastructure
providing fast Internet access is illustrated in Figure 4-5. ATM will play a role providing robust backbone data network after the head-end where the Internet traffic is separated from the TV broadcast signals.
Cable operators will likely have to rely on other companies to provide Internet content since they do not have the necessary expertise. It would be very difficult for the cable operators to compete against Internet service
provider giants such as AOL. Additionally, the cable user would prefer to have a choice in terms of selecting
