Avaya Configuring Frame Relay Services Bedienungsanleitung PDF herunterladen (Seite 33)

Frame Relay Overview

308624-14.10 Rev 01

1-11

The supervisory frames, RNR and RR, support flow control on the channel. If the

receiver is not ready to receive data, it sends an RNR message to tell the sender to

wait. When it is ready to receive data, it sends an RR message. Flow control in one

direction is independent of the other direction.

Timer T203

Timer T203 is used to detect a lost connection. When either end of the link is not

waiting for any data, it starts timer T203. If it sends or receives no frames before

this timer expires, the peer transitions to the timer recovery state, sends either an

RR or RNR message to the remote peer, and starts timer T200. If timer T200

expires, the connection is assumed lost, and the peer transitions to the

TEI-assigned state.

To terminate multiple frame support on the circuit, one peer sends a DISC

message to the other. The receiving peer responds with a UA message, and

disconnects the circuit.

SVC Signaling

The following sections describe the signaling between a DTE and the frame relay

network in which various types of messages are exchanged.

Table 1-3

contains a list of timers used in the signaling exchanges that occur.

Chapter 5, “Customizing SVCs,” describes how you can use the BCC or Site

Manager to configure these timers to your specific requirements.

Call Setup

A frame relay SVC is established using the frame relay signaling protocol

between the subscriber (DTE) and the network. This protocol is described in the

sections that follow. The timers used in this process are summarized in Table 1-3

Note that the Timer column in Table 1-3

lists the Site Manager parameter name

for the timer.

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Avaya Configuring Frame Relay Services Bedienungsanleitung Seite 33