eSpace U1960 when connected by BRI trunk, keeps on synchronizing forever and doesnt stop, ends up not connecting

Publication Date:  2016-06-10 Views:  375 Downloads:  0
Issue Description

The BRA port status is as shown below, when one BRA cable is connected: 

%eSpace U1911(config)]#Show trunkport status slot 0 portinboard 0

 

Trunk Port Status

 

----------- ------------- ------------- ---------- ---------------- ------- ---------

  GlbE1T1     BoardType     Trunkport     Office     ProtocolType     CRC     State  

----------- ------------- ------------- ---------- ---------------- ------- ---------

0           BTU           0             0          BRA              NO      NORMAL   

1           BTU           1             1          BRA              NO      PEND ACT 

2           BTU           2             2          BRA              NO      PEND ACT 

3           BTU           3             3          BRA              NO      PEND ACT 

 

------- Matched record number : [4] -------

 

====  Command executed success !  ====

 

when connect the second BRA cable the port status changes to as below:

 

%eSpace U1911(config)]#Show trunkport status slot 0 portinboard 0

 

Trunk Port Status

 

----------- ------------- ------------- ---------- ---------------- ------- ---------

  GlbE1T1     BoardType     Trunkport     Office     ProtocolType     CRC     State  

----------- ------------- ------------- ---------- ---------------- ------- ---------

0           BTU           0             0          BRA              NO      SYNC  

1           BTU           1             1          BRA              NO      SYNC 

 

the U1960 version is V200R003C00SPC100.

Alarm Information

none

Handling Process

1.  do as below steps:

Connect only one BRI trunk to U1960.  after 1 min, connect the second BRI trunk, keep on capture U1960 BRI message and Q921 message when issue happen. Then feedback the information we need. check the whole change from one BRI trunk to  two BRI trunk connected to U1960:

2.from the whole process capture. we find some issue:

The singling process has five steps when one BRI port working normal and 2 ports fail.

1/ when connects  the first BRI port, the U1900 and peer devices establish a RR link request for heartbeat, in this process we can see send & recv message, channel  normal ,

2/after connects the second port , U1900 send the RR heartbeat request without receiving the RR response from peer device.

3/ after 5 RR requests without response, the U1900 send  SABME message for establish link again.

4/ the SABME message also can’t get the response, so the U1900 send DISC message to peer device , disconnect the link.

5/ U1900 keep on sending SABME message to peer device, but never receive the response, link can’t established.

 

 3. then customer feedback the whole network diagram:

UA5000 there is only one BRI user, but the down layer BRI modem like NTI, can not communicate with two P2P U1960 BRI port. if customer hope use modem to communicate with two P2P U1960 port, the right network should be like below:

Root Cause
UA5000 there is only one BRI user, but the down layer BRI modem like NTI, can not communicate with two P2P U1960 BRI port. if customer hope use modem to communicate with two P2P U1960 port, the right network should be like below:
Solution

change the network diagram like below:

Suggestions
none

END