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Chapter 1: Networks And The Internet: What Are They
A telecommunications networks, regardless of the services 'they provide, share the following common characteristics.
1. Communications networks transport information (for example, voice, data, video) between the source and destination. Broadcast television and radio are examples where the information from one source is distributed to many different destinations.
2. Networks concentrate information. In other words, networks contain entities that concentrate information from multiple information sources prior to transmission.
3. Networks have entities that distribute information among multiple destinations.
4, Networks have entities that simply carry information from one point in the network to another. These elements are called transmission facilities or simply, facilities.
5. Networks may modify the information to improve transmission quality. Simple examples of this are analog-todigital conversion, line coding, and modulation. 6. Networks exchange information with other networks. For example, when a caller initiates a long-distance call, the information flows through at least two local exchange networks and one long-distance network. Another example is when a wireless caller calls a wireline subscriber; the information flows through a wireless network and a wireline network. The Internet transports information between people and places. It supports the transmission (real time) of text, voice, and video. The traditional voice wireline network can support the same types of information as the Internet.
Local Area Networks (LANs), Wide Area Networks (WANs), Virtual Private Networks (VPNs), the Internet, andBroadcast television are just some examples of networks.
The terms "call" and "information" are used interchangeably. Whether information is voice, video, or an electronic text/graphic file, it is all information. Networks carry information from one place to another. The Internet is a medium for information exchange and is composed of highly intelligent terminal devices that communicate across low-speed and highspeed transmission paths. The Internet's power is in the terminal devices. The wireless industry is an outstanding example of how the terminal device has become an integral part of the Internet business space. The devices currently in use appear to be the same mobile handsets that were used prior to the introduction of the mobile Internet. The user cannot physically see the differences. As far as the user is concerned, the handset looks and feels like the non-Internet models. The differences can only be seen via the services provided to the user. More information on the mobile Internet will be discussed later in this book.
Figure 1-1 is a diagram that provides a high-level view of a common telecommunications signaling network.
The reader will find that as the telecommunications network is generalized as an information network, the devices that enable information to be generated or transported are described in generic functions...
