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Use Loopback Testing for T3 Interfaces

 

This section includes the following information to assist you when troubleshooting T3 interfaces:

Checklist for Using Loopback Testing for T3 Interfaces

Purpose

To use loopback testing to isolate T3 interface problems.

Action

Table 1 provides links and commands for using loopback testing for T3 interfaces.

Table 1: Checklist for Using Loopback Testing for T3 Interfaces

Diagnose a Suspected Hardware Problem with a T3 Interface

Command or Action

  1. Create a Loopback

 

Connect the transmit port to the receive port.

[edit interfaces interface-name t3-options]

set loopback local

show

commit

  1. Set Clocking to Internal

[edit interfaces interface-name]

set clocking internal

show

commit

  1. Verify That the T3 Interface Is Up

show interfaces t3-fpc/pic/port

  1. Clear T3 Interface Statistics

clear interfaces statistics t3-fpc/pic/port

  1. Force the Link Layer To Stay Up

 

[edit interfaces interface-name]

set encapsulation cisco-hdlc

show

commit

[edit interfaces interface-name]

set no-keepalives

show

commit

  1. Verify the Status of the Logical Interface

show interfaces t3-fpc/pic/port

show interfaces t3-fpc/pic/port terse

  1. Ping the T3 Interface

ping interface t3-fpc/pic/port local-IP-address bypass-routing count 1000 rapid

  1. Check for T3 Interface Error Statistics

show interfaces t3-fpc/pic/port extensive

Diagnose a Suspected Circuit Problem
  1. Create a Loop from the Router to the Network

[edit interfaces interface-name t3-options]

set loopback remote

show

commit

  1. Create a Loop to the Router from Various Points in the Network

Perform Steps 2 through 8 from Diagnose a Suspected Hardware Problem with a T3 Interface.

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