ZyXEL Communications Prestige 861H-G1, Руководство пользователя

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Prestige 861H User’s Guide
Virtual Circuit Topology B-1
Appendix B
Virtual Circuit Topology
ATM is a connection-oriented technology, meaning that it sets up virtual circuits over which end
systems communicate. The terminology for virtual circuits is as follows:
•
Virtual Channel Logical connections between ATM switches
•
Virtual Path A bundle of virtual channels
•
Virtual Circuit A series of virtual paths between circuit end points
Diagram B-1 Virtual Circuit Topology
Think of a virtual path as a cable that contains a bundle of wires. The cable connects two points
and wires within the cable provide individual circuits between the two points. In an ATM cell
header, a VPI (Virtual Path Identifier) identifies a link formed by a virtual path; a VCI (Virtual
Channel Identifier) identifies a channel within a virtual path.
The VPI and VCI identify a virtual path, that is, termination points between ATM switches. A
series of virtual paths make up a virtual circuit.
Your service provider should supply you with VPI/VCI numbers.