Prestige 642R Series ADSL Router

Appendix B

Virtual Paths and Channels

VPI & VCI

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:

z

VC (virtual channel)

Logical connections between end stations

z

VP (virtual path)

A bundle of VCs

Think of a VP 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 and a VCI (Virtual Channel Identifier) identifies a channel within a virtual path. The VPI and VCI are identified and correspond to termination points at ATM switches as shown. Your telephone company should supply you with these numbers.

Diagram 3 VPI's & VCI's

H

Virtual Path and Channels

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ZyXEL Communications 642R Series manual Appendix B Virtual Paths and Channels, Diagram 3 VPIs & VCIs