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You can configure an error rate to force errors in the bit stream:<br />

[edit interfaces t1-0/0/3]<br />

aviva@RouterF# set t1-options bert-error-rate 3<br />

This configuration generates one error in every 1,000 packets (10e-3). The show<br />

interfaces command output shows the number of errors and the error rate:<br />

aviva@RouterF> show interfaces t1-0/0/3 extensive | find bert<br />

DS1 BERT configuration:<br />

BERT time period: 10 seconds, Elapsed: 10 seconds (completed)<br />

Induced Error rate: 10e-3, Algorithm: 3 in 24, Repetitive (26)<br />

Bit count : 15369016<br />

Error bit count: 15355<br />

Error rate: 10e-3.0<br />

7.19 Configuring Frame Relay on a T1 Interface<br />

Problem<br />

You have a router that provides Frame Relay circuits to your customers. You want to<br />

set up a back-to-back connection between your router and that of a customer.<br />

Solution<br />

Use the following commands to configure Frame Relay:<br />

[edit interfaces t1-0/0/3]<br />

aviva@RouterF# set description "J2300 T1 line in local office"<br />

aviva@RouterF# set encapsulation frame-relay<br />

aviva@RouterF# set dce<br />

aviva@RouterF# set unit 0 description "Customer A"<br />

aviva@RouterF# set unit 0 dlci 100<br />

aviva@RouterF# set unit 0 family inet address 10.0.13.2/24<br />

<strong>Discussion</strong><br />

Frame Relay is a point-to-point technology that switches packets through a network<br />

instead of routing them. The paths through the network are called virtual circuits<br />

(VCs). Each VC is identified by a Data Link Connection Identifier (DLCI), which is a<br />

number from 0 to 1023. In the JUNOS software, DLCIs 0 through 15 are reserved,<br />

so you can use 16 through 1023 to carry traffic. Generally, you might want to configure<br />

Frame Relay on slower interfaces, such as T1, serial, or ISDN.<br />

You configure each VC on a separate logical interface, setting a DLCI number and IP<br />

address. You also set the encapsulation to frame-relay on the physical interface itself.<br />

On the remote side of the VC, you configure a DLCI that has the same number.<br />

Because the two router interfaces are in a back-to-back configuration, include the set<br />

dce command on one end of the link to have the router look like a Frame Relay switch.<br />

Configuring Frame Relay on a T1 Interface | 231<br />

This is the Title of the Book, eMatter Edition<br />

Copyright © 2008 O’Reilly & Associates, Inc. All rights reserved.

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