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is chosen only when a message is sent. There is no pre-arrangement, so each
virtual connection exists only for the duration of that one transmission.
VPI
Virtual Path Identifier. Identifies virtual paths between users or between users and
networks.
W
WAN
Wide Area Networks link geographically dispersed offices in other cities or around
the globe. Just about any long-distance communication medium can serve as a
WAN link, including switched and permanent telephone circuits, terrestrial radio
systems, and satellite systems.