Avaya M-ACCF/SF manual Switching Cells Using VPI and VCI Values, Switched Virtual Circuits SVCs

Chapter 1 Overview

Connections that are established dynamically using the Signalling protocol are known as Switched Virtual Circuits (SVCs). Switched Virtual Circuits are described on Page 20.

ATM connections can also be established via management, and these type of connections are known as Permanent Virtual Circuits (PVCs).

Figure 1.12 Switching Cells Using VPI and VCI Values

M770 Multifunction

Switch with M-ACC

VPI = 6

VCI = 412

H DATA

UNI

	Each cell is switched through the
	ATM network. The VPI/VCI values
	in the cell header are translated by
Avaya P117F/FR	each ATM Switch along the path.
M770 ATM Switch		M770 ATM Switch

VPI = 1

VCI = 117

	H	DATA
NNI			UNI

VPI = 3 VCI = 35

H DATA

Switched Virtual Circuits (SVCs)

SVCs use the signalling protocol to dynamically define connections as they are needed and to release them when they are no longer needed.

SVCs use signalling for:

•Connections initiated by the user/application.

•Connections established and dropped dynamically.

•Varied connection time.

•Connections not automatically re-established after network failure.

Note: The ATM access module does not support PVCs.

20 Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide