In most cases, the switches in a WAN are Frame
Relay switches.
DCE or Frame
Relay Switch
Frame Relay works here.
326 Chapter 8: Extending the Network into the WAN
Frame Relay provides a means for statistically multiplexing many logical data
conversations, referred to as virtual circuits (VC), over a single physical transmission link
by assigning connection identi?¬?ers to each pair of DTE devices. The service provider
switching equipment constructs a switching table that maps the connection identi?¬?er to
outbound ports. When a frame is received, the switching device analyzes the connection
identi?¬?er and delivers the frame to the associated outbound port. The complete path to the
destination is established prior to the transmission of the ?¬?rst frame. Figure 8-22 illustrates
a Frame Relay connection and identi?¬?es the many components within Frame Relay.
Figure 8-22 Frame Relay Components
The following terms are used frequently in Frame Relay discussions and can be the same
or slightly different from the terms your Frame Relay service provider uses:
?– Local access rate: Clock speed (port speed) of the connection (local loop) to the
Frame Relay cloud.
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