Panasonic 1200N - Manual (Page 247)

Glossary W
Centillion 1200N ATM Switch User Manual B-85
NTP 297-8103-903
VPI
Virtual Path Identifier: An eight bit field in the ATM cell header which indicates
the virtual path over which the cell should be routed.
VPL
Virtual Path Link: A means of unidirectional transport of ATM cells between the
point where a VPI value is assigned and the point where that value is translated or
removed.
VPT
Virtual Path Terminator: A system that unbundles the VCS of a VP for independent
processing of each VC.
VS
Virtual Scheduling: Virtual Scheduling is a method to determine the conformance
of an arriving cell. The virtual scheduling algorithm updates a Theoretical Arrival
Time (TAT), which is the "nominal" arrival time of the cell assuming that the active
source sends equally spaced cells. If the actual arrival time of a cell is not "too"
early relative to the TAT, then the cell is conforming. Otherwise the cell is non-
conforming.
VS
Virtual Source. Refer to VS/VD.
VS/VD
Virtual Source/Virtual Destination: An ABR connection may be divided into two
or more separately controlled ABR segments. Each ABR control segment, except
the first, is sourced by a virtual source. A virtual source implements the behavior
of an ABR source endpoint. Backwards RM-cells received by a virtual source are
removed from the connection. Each ABR control segment, except the last, is
terminated by a virtual destination. A virtual destination assumes the behavior of
an ABR destination endpoint. Forward RM-cells received by a virtual destination
are turned around and not forwarded to the next segment of the connection.
W
WAN
Wide Area Network: A network which spans a large geographic area relative to
office and campus environment of LAN (Local Area Network). WAN is
characterized by having much greater transfer delays due to laws of physics.