Technical Documentation

Configure a Local Loopback


To configure a local loopback, follow these steps:.

Note: For a list of interface types associated with the Channelized OC12 IQ interface, see the JUNOS Network Interfaces Configuration Guide.

  1. In configuration mode, go to the following hierarchy level:
    [edit]user@host# edit interfaces t3-fpc/pic/port:channel t3-options
  2. Configure the local loopback:
    [edit interfaces t3-fpc/pic/port:channel t3-options] user@host# set loopback local

    The following is an example of the name for a T3 channel on a channelized DS3 interface:

    [edit interfaces t3-2/1/0:2 t3-options]
  3. Verify the configuration:
    user@host# show

    For example:

    [edit interfaces t3-2/1/0:2 t3-options]user@host# show loopback local;
  4. Commit the configuration:
    user@host# commit

    For example:

    [edit interfaces t3-2/1/1:2 t3-options]user@host# commit commit complete


When you create a local loopback, you create an internal loop on the interface being tested. A local loopback loops the traffic internally on that PIC. A local loopback tests the interconnection of the PIC but does not test the transmit and receive ports.

Note: Remember to delete the loopback statement after completing the test.

Published: 2010-01-29