Network Types: WANs

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A Wide Area Network connects computers in locations throughout the country or even overseas. Most WANs will be made up of a number of LANs connected by long-distance, high-speed data links.

Technologies and Services used with WANs include:

  1. X.25: (packet switching network) X.25 networks are owned by long distance telecommunications providers who charge for acces to the network.
  2. ISDN: (Integrated Services Digital Network) is a digital communications specification that accommodates, Data, Video, Voice. The specification was originally designed to replace the analog PSTN. The goal is to eventually run ISDN to every household and business in the world. Meanwhile, ISDN is being used primarily to link LANs. ISDN has a few disadvantages. It is limited to a maximum throughput of about 1.5Mbps, which makes it unsuitable as a network backbone.
  3. Frame Relay: (advanced packet-switching network) that uses variable length packets.
  4. ATM: (Asynchronous Transfer Mode) is a high-speed packet-switching technology that uses a fixed-size packet. A unique feature of ATM is that it is equally adaptable to both broadband and baseband signaling, making ATM suitable for both LANs and WANs. With transfer speeds ranging between 155Mbps and 622Mbps. ATM networks require switches and use multiplexing technology to combine information from voice, and data sources into a single information stream.
  5. FDDI: (Fiber Distributed Data Interface) is a standard that uses fiber-optic cable and a token-passing media access control method to provide a tranfer speed of 100Mbps. FDDI was designed for high-end workstations and servers that need more bandwitdh than a 10-Mbps Ethernet or 16Mbps token ring can provide.
  6. SONET: (Synchronous Optical Network) is a relatively new networking standard based on fibre-optic cable that delivers transfer speeds in excess of one gigabit per second.

All the above was copied from Chapter 6: Wide Area Networks: pages 109 throgh to 125. MCSE Networking Essentials for Dummies 2nd Edition: Author: Robert Aschermann. Excuse any bits missing or taken out of context. It is intended only as an overview to the Networking Topic.