test interface fdl-line-loop

Syntax

Release Information

Description

Send commands over the facilities data link (FDL) on a T1 interface to initiate or terminate a far-end line loopback using either an ANSI or Bellcore FDL command code. If the far end of the connection is in C-bit parity mode and it has been configured to accept line loopback requests from the near end, the far end executes the request. See the ANSI T1.107 specification for more details.

Note: The following restrictions apply to this command: If you attach a SmartJack network interface unit (NIU) on the T1 connection between an M-series router with a channelized DS3 IQ, channelized OC3 IQ, or channelized OC12 IQ interface and a standard T1 interface, and you issue the test interface fdl-line-loop bellcore initiate command on the channelized T1 interface, the loopback test might not function correctly. On Channelized DS3-to-DS1 and Multichannel DS3 PICs, this command can only be initiated by T1 interfaces. These types of T1 interfaces cannot accept a request for this test sent by another router. This command is not supported on the 4-port T1 PIC.

Options

ansi — ANSI FDL command code.

bellcore — Bellcore FDL command code.

initiate — Initiate the far-end line loopback.

terminate — Terminate the far-end line loopback.

t1-fpc/pic/port<:channel> — Name of a T1 interface. The channel number indicates a channelized interface.

Required Privilege Level

view

List of Sample Output

Output Fields

To display the state and the number of times the interface has placed itself into remote loopback, use the show interfaces extensive command.