Huawei, ZTE, Nokia, Alcatel Lucent, Fiberhome Network Hardware Store

Issue Description
As a user network egress, the ME60A accesses the Internet through the ME60B. ME60A and ME60B communicate with each other through the MP-Group link and pass through the transmission device. The MP-Group is bundled by eight CE1 links. It is found that users connected to the ME60A are unstable on the Internet, and sometimes they can ping the DNS normally while sometimes the delay is large, the packet loss is serious, and even the webpage cannot be opened.

Handling Process

1. On the transmission device, check the status of the physical port and the optical fiber respectively, and find that the physical port and the optical fiber are normal.
2. On the ME60 A and ME60 B, use thedisplay interfacecommand to view information about the MP-Group interface and member ports.

Check the following information for each interface separately:
l  Whether the interface status is Up
l  Is the clock mode correct?
l  Is the line codec format consistent at both ends?
l  Whether to configure loopback
l  Whether there is an alarm

[ME60A] display controller e1 1/0/0
E1 1/0/0 current state : UP
Description : E1 1/0/0 Interface
Physical layer is Packet Over NO-CRC4
clock slave, linecode hdb3 , loopback none
section layer:
    alarm:  LOS
line layer:
    alarm:  none
path layer:
    alarm:  none
[ME60B] display controller e1 1/0/0
E1 1/0/0 current state : UP
Description : E1 1/0/0 Interface
Physical layer is Packet Over NO-CRC4
clock master, linecode hdb3 , loopback none
section layer:
    alarm:  LOS
line layer:
    alarm:  none
path layer:
    alarm:  none

 
The CE1 interface of the ME60A is configured with a slave clock, and the CE1 interface of the ME60B is configured with a master clock.
 
Root Cause
Since the link passes through the transmission device, the ME device needs to obtain the clock information from the transmission device. Therefore, it is determined that the clock configuration error causes the link to be unstable.
 
Solution

1. On the ME60B, run the system-view command to enter the system view.
2. Run thecontroller e1 1/0/0 command to enter the CE1 interface view.
3. Run theclock slave command to change the clock mode of the CE1 interface to the slave clock mode.
4. Do the same on each member port of the MP-Group in turn.
5. After the configuration is complete, check the status of the CE1 interface on the MEs at both ends. The link is stable, the packets are sent and received, and the fault is rectified.

 
Suggestions
When the CE1 interface is used as a synchronous interface, there are two working modes: DTE and DCE. You need to select the clock mode.
 
The CE1 interface can select two clock modes:
Main clock mode: Use the internal clock signal.
Slave clock mode: Use the clock signal provided by the line.
When the CE1 interfaces of the two devices are directly connected, one end should be set as the master clock (Master) and the other end as the slave clock (Slave).
When the CE1 interface of the device is connected to the transmission device, the CE1 interface of the device must act as a slave clock and use the clock signal provided by the transmission device.