12 IEEE POTENTIALS 0278-6648/05/$20.00 © 2005 IEEE Broadband refers to the telecommunication in which a wide band of frequencies are available to transmit data. Broadband communication supplies multiple channels of data in single communications platform using some form of wave or frequency division multiplexing. With broadband, services such as data, voice, and video, commonly known as multimedia, can be deliv- ered together as one packet. To receive broadband services you must have broadband access, and broadband access is the major issue in terms of allowing new applications to be utilized. Some of the net- works that are available for providing these types of ser- vices are asynchronous transfer mode (ATM), frame relay, and leased lines. These networks are instrumental in supplying customers with broadband ser- vices that have the potential of eventually overtaking the tradi- tional dial-up Internet. Broad- band communication systems distribute broadband services on the transmit end and also allow access to the services transmitted by the broadband provider on the receive end. Typical broadband communication network system Figure 1 shows a typical broadband communication net- work, which consists of the central office (CO) and the res- idential and business (user) sections. The CO is made up of the digital subscriber line access multiplexer (DSLAM) that handles all the traffic gen- erated from the user (residen- tial or business) and the data center. The DSLAM takes con- nections from many customers and puts them on a single high-speed connection to the Internet. Figures 2 and 3 show the individual sections of the typical broadband network. Figure 2 shows a diagram of the DSLAM and switch together in the CO for access to the public switched telephone net- work (PSTN) and Internet. The ATM switch in Fig. 2 is a local exchange switch that allows a connec- tion to the PSTN for telephone access. The Internet service provider (ISP) is the company that provides the Internet services that the customer pays for. The CO is connected to two types of cus- tomers: residential and business. Cus- tomers will have different equipment that allows them to access the network. Figure 3 is a diagram of the typical setup of an office network used by a business customer. The proxy server in Fig. 3 acts as an intelligent access point between the business user and the Internet to pro- vide security, administrative control, and caching service for the business LAN. The proxy server as a whole sep- arates the business’s internal network from the outside network. The ADSL bridge in Fig. 3 connects the LAN of the reference business user to another LAN with the same type of network protocol. The bridge is intelligent enough to decipher whether to “pass” information sent by a user that is intended for someone inside the same network LAN or to “forward” the data if it is intended for someone outside the reference network to an interconnected LAN. The ADSL bridge also separates the user’s telephone usage from Inter- net usage. In the residential network, the user needs the DSL modem for high-speed Internet access. Ethernet cable, also known as CAT 5, is used to connect the DSL to the computer. A filter for the phone line is needed so that certain sig- nals cannot be passed through that could potentially damage the phone system. A cable modem could also be ©DIGITAL VISION CAJETAN M. AKUJUOBI AND MATTHEW N.O. SADIKU The present and future of broadband communications