Troubleshooting E1/T1 Interfaces - H3C MSR Series Troubleshooting Manual

Enable PPP encapsulation on the interface.
1.
Display the interface information.
2.
If the command output shows that the number of received packets evenly increases by 12
packets, loopback is detected, and no error packets appear, the link is normal.
Otherwise, the link fails.
[H3C]dis int ser 1/0:0
Serial1/0:0
Current state: UP
Line protocol state: DOWN
Description: Serial1/0:0 Interface
Bandwidth: 64kbps
Maximum Transmit Unit: 1500
Hold timer: 10 seconds, retry times: 5
Derived from E1 1/0, Timeslot(s) Used: 1, Baudrate is 64000 bps
Internet protocol processing: disabled
Link layer protocol: PPP, Loopback: detected
LCP: closed
Output queue - Urgent queuing: Size/Length/Discards 0/100/0
Output queue - Protocol queuing: Size/Length/Discards 0/500/0
Output queue - FIFO queuing: Size/Length/Discards 0/75/0
Last clearing of counters: Never
Last 300 seconds input rate: 0.00 bytes/sec, 0 bits/sec, 0.00 packets/sec
Last 300 seconds output rate: 0.00 bytes/sec, 0 bits/sec, 0.00 packets/sec
Input:
12 packets, 156 bytes
0 broadcasts, 0 multicasts
0 errors, 0 runts, 0 giants
0 CRC, 0 align errors, 0 overruns
0 aborts, 0 no buffers, 0 frame errors
Output:
12 packets, 156 bytes
0 errors, 0 underruns, 0 collisions
0 deferred
Use the error code meter to troubleshoot lines
Replace the router with an error code meter.
3.
Connect the Rx and Tx cables previously connected to the router to the error code meter.
4.
In this case, the error code meter can display whether error codes exist on the line.

Troubleshooting E1/T1 interfaces

Common E1/T1 module problems include the following types:
•
Physical interface anomaly, for example, the LOS, LFA, AIS, or RAI alarms exist on the
controller interface and the controller interface stays down or flaps.
•
The physical interface is up, and has no alarms. However, the data cannot be sent or received
properly. For example, error packets exist on the local and peer interfaces, and the link layer
protocol comes up and go down.
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