Virtual Circuits

Frame Relay provides significant advantages over simply using point-to-point leased lines. The primary advantage has to do with VCs. Consider Figure 13-3, which shows a typical Frame Relay network with three sites.

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Figure 13-3 Typical Frame Relay Network with Three Sites

A VC defines a logical path between two Frame Relay DTEs. The term virtual circuit describes the concept well. It acts like a point-to-point circuit, enabling the sending of data between two endpoints over a WAN. There is no physical circuit directly between the two endpoints, so it is virtual. For example, R1 terminates two VCs—one whose other endpoint is ...

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