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Knowledge Base

2M crystal head line’s sequence is incorrect, Huawei router and C router failed to get a connection.

Publication Date:  2012-09-19  |   Views:  954  |   Downloads:  0  |   Document ID:  EKB1000015203


Issue Description

Huawei AR28-31crouter and C Co.72XX router can not connect to each other.Each end can not ping other IP address.

Alarm Information


Handling Process

1. Check data configuration
2. Check physical link.
Huawei AR28-31 router 2M module dual in-line package switch show 75 ohm,but its transfers impedance is 120 ohm. Dial AR28-31 router 2M module dual in-line package switch to 120 ohm . Debug it again and find the problem cannot be solved
Taking link local loopback  test,the receive and the send have been set wrong. fter re-adjustment and detection, found that the problem is still not resolved. Further link loopback test, can found that when  let C Co. 72XX router do loopback test, ort sometimes UP sometimes down.
Go through C Co. 72 XX router side cable 2M line and crystal head, the order of the 2 M line’s crystal head line is wrong. The order of the C company router 2 M line’s crystal head line is 1245.Remake 2 M line crystal head and test connectivity, problem has been solved.

Root Cause

Docking barrier, usually two reasons:
1.Data configuration error.
2.Physical link failure.


When routers docking barrier, attention to check physics linking whether is correct or not:
1. Don’t set backward the receive and send of device’s 2M line .
2.The order of the C company router 2 M line crystal head line is 1245.