ZyXEL p-660h-61 用户指南
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Prestige 660H Series User’s Guide
Virtual Circuit Topology
D-1
Appenidx D
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:
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 D-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.
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.
of virtual paths make up a virtual circuit.
Your service provider should supply you with VPI/VCI numbers.