Performing Loopback Tests - Cisco 10000 Series Configuration Manual

Interface Configuration Commands

Performing Loopback Tests

Use the loopback command to assign an E3 or T3 interface into loopback test using the following
format:
[no] loopback network [line | payload]
[no] loopback [local | remote]
Where:
•
•
•
•
The default is no loopback.
To cancel a loopback test, use the no form of the command.
In the following example, the loopback network is set to line:
Router(config)# dsx3 1/0/0
Router(config-if)# network loopback line
See the
Internet Router Troubleshooting Guide
Entering MDL Messages
Use the maintenance data link (MDL) message strings and codes to send messages in response to far-end
inquiries.
MDL messages are supported only when the T3 framing is set to c-bit (see the
Note
Type" section on page
You can configure MDL messages (as defined in the ANSI T1.107a-1990 specification) on a T3 interface
using the mdl command in the following format:
[no] mdl
port
Where:
•
•
Cisco 10000 Series Router Line Card Configuaration Guide
15-14
network line loops the data back to the network
network payload loops the payload portion back to the network
local loops the line card output data back toward the line card and sends an AIS message
remote sends a far end alarm control (FEAC) request to the far-end (remote) device, requesting that
it enter a network line loopback
A remote loopback test is possible only when the line is configured for c-bit framing.
Note
Cisco IOS Interface and Hardware Component Configuration
15-13.)
{ { |
transmit path idle-signal
| }
generator id_string
transmit enables one of the following transmissions:
path enables transmission of the MDL path message
–
idle-signal enables transmission of the MDL idle-signal message
–
test-signal enables transmission of the MDL test-signal message
–
string enables one of the following identification codes:
Chapter 15
for details about loopback testing.
|
test-signal
}
8-Port Unchannelized E3/T3 Line Card Configuration
Guide, and the Cisco 10000 Series
"Setting the Framing
} | { | |
string eic lic fic
| | |
unit pfi
OL-8834-04