WANs

The best known wide area network is, of course, the Internet. Its area is now pretty much all of the populated world. In addition, however, many businesses have created wide area networks of their own. Most of these use IBM's SNA protocol suite, while others use TCP/IP with wires, routers, and switches that are physically separate from the Internet. Nearly all wide area connections currently use the SONET protocols, but there is intense interest in moving to simpler approaches. We'll discuss SONET first.

SONET

SONET, which stands for Synchronous Optical Network, takes us back to Layer 1. This is a physical transport that uses (exclusively) optical cable and synchronous time slot data management. SONET, also known in international standards ...

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