Hello everyone,
This post refers to the serial interface troubleshooting procedure. Please read below for more details.
1.Common Causes
This fault is commonly caused by one of the following:
l Cables at both ends are incorrectly connected.
l Configurations at both ends are inconsistent.
2.Troubleshooting Flowchart
Figure 1-1 shows the troubleshooting flowchart.
Figure 1-1 Troubleshooting
flowchart for statistics on sent and received data packets are incorrect on the
serial interface
3.Troubleshooting Procedure
Saving the results of each troubleshooting step is recommended. If your troubleshooting fails to correct the fault, you will have a record of your actions to provide Huawei technical support personnel.
Procedure
Step 1 A synchronous/asynchronous serial interface works in DTE or DCE mode. One device functions as the DTE and the other device functions as the DCE. Verify that the directly connected cable between the DCE and DTE is delivered by Huawei.
l If the directly connected cable between the DCE and DTE is not delivered by Huawei, replace the cable.
l If the directly connected cable between the DCE and DTE is delivered by Huawei, go to step 2.
Step 2 Verify that the pin assignment is correct.
l If the pin assignment is incorrect, correct the pin assignment.
l If the pin assignment is correct, go to step 3.
Step 3 Perform local loopback to check whether the 1SA/2SA card works properly.
Run the loopback local command in the serial interface view to check the serial interface configuration.
l If the 1SA/2SA card does not work properly, replace the 1SA/2SA card.
l If the 1SA/2SA card works properly, go to step 4.
Step 4 Verify that the configurations of the local and remote physical interfaces are consistent.
Run the display this command in the serial interface view to check the serial interface status.
Check whether physical attributes of two interfaces are consistent. The two interfaces must use the same operation mode, coding format, and idle code except the clock mode. The two interfaces must use different clock modes, that is, one end uses the master clock, and the other end uses the slave clock.
l If the two interfaces have inconsistent configurations or frequently alternate between Up and Down states, reconfigure them.
l If the two interfaces have consistent configurations and remain Up, go to step 5.
Step 5 View interface statistics on the local device and check whether there are a large number of error packets in the inbound direction.
<Huawei> display interface serial 1/0/0
Serial1/0/0 current state :
UP
Line protocol current state :
UP
Description:HUAWEI, AR Series, Serial1/0/0 Interface
Route Port,The Maximum Transmit Unit is 1500, Hold timer is
10(sec)
Internet protocol processing :
disabled
Link layer protocol is
PPP
LCP
initial
Last physical up time : 2013-01-02 00:14
UTC+08:00
Last physical down time : 2013-01-02 00:14
UTC+08:00
Current system time: 2013-01-02 00:14+08:00
Physical layer is synchronous, Virtualbaudrate is 64000
bps
Interface is DTE, Cable type is V35, Clock mode is
TC
Last 300 seconds input rate 2 bytes/sec 16 bits/sec 0
packets/sec
Last 300 seconds output rate 0 bytes/sec 0 bits/sec 0
packets/sec
Input: 9714 packets, 213708
bytes
Broadcast:
0,
Multicast:
0
Errors: 0, Runts: 0
Giants: 0, CRC: 0
Alignments: 0, Overruns: 0
Dribbles:
0, Aborts: 0
No
Buffers:
0, Frame
Error:
0
Output: 0 packets, 22
bytes
Total
Error:
0,
Overruns:
0
Collisions:
0,
Deferred:
0
DCD=UP DTR=UP DSR=UP RTS=UP
CTS=UP
Input bandwidth utilization :
0.10%
Output bandwidth utilization :
0%
l If there are a large number of error packets in the inbound direction, run the invert receive-clock command to configure the device to invert clock signals received by a synchronous serial interface.
l If there is no error packet in the inbound direction, go to step 6.
Step 6 View interface statistics on the remote device and check whether there are a large number of error packets in the inbound direction.
l If there are a large number of error packets in the inbound direction, run the invert transmit-clock command to configure the device to invert clock signals sent by a synchronous serial interface.
l If there is no error packet in the inbound direction, go to step 7.
Step 7 Verify that the virtual baud rate (virtualbaudrate) on the DTE is the same as the baud rate (baudrate) on the DCE. If the baud rates are different, packets are discarded.
l If the baud rates are different, set the baud rates to be the same.
l If the baud rates are the same, go to step 8.
Step 8 Collect the following information and contact technical support personnel.
l Results of the preceding troubleshooting procedure
l Configuration file, logs, and alarms of the device
