AR failed to connect Cisco router via E1 interface

Publication Date:  2014-04-26 Views:  806 Downloads:  0
Issue Description
AR 2200 connects to Cisco-2811 via E1120-ohm balanced twisted pair cable, but the ports on both sides cannot be up.
Alarm Information
None
Handling Process
1. After checking E1120-ohm balanced twisted pair cable, the pin assignments on Cisco and AR is correct as below:

cisco E1(RJ45)     AR E1(RJ45) 
      
4 (TX+)                       1(RX+)
5 (TX-)                        2(RX-)
1 (RX+)                       4(TX+)
2 (RX-)                        5(TX-)

2. After self-loopback test on AR and Cisco with E1, found that hardware are working well.

<Huawei> display fe1 serial 1/0/0
Serial1/0/0 is UP                                                          
Basic Configuration:                                                           
  Work Mode is E1 Fractional Framed, Cable type is 120 Ohm balanced.           
  Frame-format is NO-CRC4, Line Code is Hdb3.                                  
  Source Clock is Slave, Data-coding is Normal.                                
  Idle code is 7E, Itf type is 7E, Itf number is 4.                            

3. Checking the configuration, Frame-format on Cisco is CRC4, but Huawei is NO-CRC4 by default

Configuration on Cisco:

AHQ#sh controller E1 0/0/0
E1 0/0/0 is down.
  Applique type is Channelized E1 - balanced
  Transmitter is sending remote alarm.
  Receiver has loss of frame.
  alarm-trigger is not set
  Version info Firmware: 20060711, FPGA: 13, spm_count = 0
  Framing is CRC4, Line Code is HDB3, Clock Source is Line.
  CRC Threshold is 320. Reported from firmware  is 320.

Configuration on AR 2200:

<Huawei> display fe1 serial 1/0/0
Serial1/0/0 is down                                                         
Basic Configuration:                                                          
  Work Mode is E1 Fractional Framed, Cable type is 120 Ohm balanced.          
  Frame-format is NO-CRC4, Line Code is Hdb3.                                 
  Source Clock is Slave, Data-coding is Normal.                               
  Idle code is 7E, Itf type is 7E, Itf number is 4.       

4. Modify the frame-format to CRC4 on AR 2200, the E1 link get up finally.
[Huawei] interface serial 1/0/0
[Huawei-Serial1/0/0] fe1 frame-format crc4
[Huawei] display fe1 serial 1/0/0
Serial1/0/0 is UP                                                        
Basic Configuration:                                                         
  Work Mode is E1 Fractional Framed, Cable type is 120 Ohm balanced.         
  Frame-format is CRC4, Line Code is Hdb3.                                
  Source Clock is Slave, Data-coding is Normal.                              
  Idle code is 7E, Itf type is 7E, Itf number is 4.   
Root Cause
The following problems may cause E1 connection failed:
1. pin assignments of cable is incorrect
2. hardware failed
3. configuration on both sides is inconsistent
Suggestions
When E1 link failed, pleas check pin assignments of E1 cable、hardware of the E1 ports and parameter on both sides should be consistent.

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