Create a Loop from the Router to the Network

To create a loop from the router to the network, follow these steps:

1. Loop the Entire T3 Interface towards the Network
2. Loop a Particular T1 Channel towards the Network

Loop the Entire T3 Interface towards the Network

Purpose

Creating a loop from the entire T3 interface to the network allows the transport-layer engineer to test the router from various points in the network and isolate the problem.

Action

To create a loop from the entire T3 interface to the network, follow these steps:

1. In configuration mode, go to the following hierarchy level:

   [edit]

   user@host# edit interfaces interface-name t3-options

2. Configure the loopback:

   [edit interfaces interface-name t3-options]

   user@host# set loopback remote

3. Verify the configuration:

   user@host# show

   For example:

   [edit interfaces t3-2/1/1:0 t3-options]

   user@host# show

   loopback remote;

4. Commit the configuration:

   user@host# commit

Meaning

The loopback remote command loops any traffic from the network back into the network.

The interface name is one of the following:

• T1 channel 0, channel group 0, on the Multichannel DS3 port for a channelized DS3 to DS0 interface (for example, ds-2/1/1:0:0)
• T1 channel 0 on the Multichannel DS3 port for a channelized DS3 to DS1 interface (for example, t1-2/1/1:0)

Loop a Particular T1 Channel towards the Network

Purpose

Creating a loop from a particular T1 interface to the network allows the transport-layer engineer to test the T1 interface from various points in the network and isolate the problem.

Action

To create a loop from a particular T1 interface to the network, follow these steps:

1. In configuration mode, go to the following hierarchy level:

   user@host# edit interfaces interface-name t1-options

2. Configure the loopback:

   [edit interfaces interface-name t1-options]

   user@host# set loopback remote

3. Verify the configuration:

   user@host# show

   For example:

   [edit interfaces ds-2/1/1:0:0 t1-options]

   user@host# show

   loopback remote;

4. Commit the configuration:

   user@host# commit

Meaning

This command loops any traffic from the network back into the network. The interface name is one of the following:

• Channel group 0 for the particular T1 channel on the Multichannel DS3 port for a channelized DS3 to DS3 interface (for example, ds-2/1/1:2:0)
• Particular T1 channel on the Multichannel DS3 port for a channelized DS3 to DS1 interface (for example, t1-2/1/1:3)