ZyXEL Communications 641 manual Appendix B, Diagram 3 VPIs & VCIs

Prestige 641 ADSL Internet Access Router

Appendix B

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:

•VC (virtual channel) Logical connections between end stations

• 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.

Appendix B G