Using Frame Relay; Overview Of Frame Relay; Pvcs And Dlcis - Lucent Technologies PortMaster 4 Configuration Manual

Table of Contents

Frame Relay is a method of encapsulating network information that allows for fast

delivery and high line utilization. PortMaster routers support Frame Relay over

synchronous ports.

This chapter uses an example to demonstrate how to configure the PortMaster 4 to

connect to a synchronous line using Frame Relay. This chapter also explains how to

configure Frame Relay subinterfaces.

The following topics are discussed:

•

"Overview of Frame Relay" on page 12-1

•

"Frame Relay Configuration on the PortMaster" on page 12-3

•

"Configuring a T1 or E1 Line for Frame Relay" on page 12-4

•

"Troubleshooting a Frame Relay Configuration" on page 12-7

•

"Frame Relay Subinterfaces" on page 12-8

See the PortMaster 4 Command Line Reference for more detailed command descriptions and

instructions.

You can also configure the PortMaster 4 using the PMVision application for Microsoft

Windows, UNIX, and other platforms supporting the Java Virtual Machine (JVM).

PMVision replaces the PMconsole interface to ComOS.

Overview of Frame Relay

Frame Relay is a switched digital service that supports multiple virtual circuits,

simultaneously connected to a site by a single physical circuit. Each site requires only

one physical circuit into the Frame Relay network—usually referred to as a cloud—but

can have several virtual circuits to reach other sites attached to the cloud.

You configure synchronous ports on the PortMaster 4 to support Frame Relay

connections. As opposed to a dedicated or leased line, a Frame Relay connection can be

thought of as a virtual switch.

PVCs and DLCIs

Permanent virtual circuits (PVCs) are used to form a connection between any two

devices attached to a Frame Relay cloud. Each PVC is given a unique number on each

physical circuit along the path between the two devices. This unique number is called a

data link connection identifier (DLCI). The DLCI is automatically changed to the PVC

number of the next physical circuit as it passes through each switch along the path. A

DLCI is different from a network address in that it identifies a circuit in both directions,

not a particular endpoint. A frame contains only one DLCI, not a source and

destination.