Checklist for Using Loopback Testing for Multichannel DS3 Interfaces

Purpose

To use loopback testing to isolate Multichannel DS3 interface problems.

Action

Table 52 provides links and commands for using loopback testing for Multichannel DS3 interfaces.

Table 52: Checklist for Using Loopback Testing for Multichannel DS3 Interfaces

Tasks

Command or Action

Diagnose a Suspected Hardware Problem with a Multichannel DS3 Interface
  1. Create a Loopback
 

Connect the TX port to the RX port.

[edit interfaces interface name (t3-options | t1-options)]
set loopback local
show
commit

  1. Verify That the Interface Is Up

show interfaces (ds-fpc/pic/port:channel:channel | t1-fpc/pic/port:channel)

  1. Clear Interface Statistics

clear interfaces statistics (t1-fpc/pic/port:channel | ds-fpc/pic/port:channel:channel)

  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 (ds- fpc/pic/port:channel:channel | t1-fpc/pic/port:channel)

  1. Ping the Channelized Interface

ping interface (ds-fpc/pic/port:channel:channel | t1-fpc/pic/port:channel) local-IP-address bypass-routing count 1000 rapid

  1. Check for Interface Error Statistics

show interfaces (ds-fpc/pic/port:channel:channel | t1-fpc/pic/port:channel) 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

[edit interfaces interface-name t1-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 Multichannel DS3 Interface.

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