I experience this just today and now sharing with you.

Problem Description: BUS_ERR alarm occurred after cross-connection between TN53TDX & TN12ND2 board

Investigation:

As this is 10GE LAN service following parameter checked one by one.

1. Service type: 10GE LAN in TDX Board & Speedup mode in ND2 board
   
2. Cross-connection Type: ODU2
3. Cross-connection board: Working(TN11XCS) & protection (TN12XCS)         

Solution: TN11XCS board changed with another new TN12XCS version and problem solved.

We have faced this alarm, here some trigger reasons:

 

1. Missmatch between line rate set between tributary and line board.

2. Line board broken.

Great answer #2! I have faced that alarm before and the problem was a missmatch between line rate of TDX and ND2, after chage the line rate in TDX the problem was solved.

I recommend to check in support website the troubleshooting cases before replacing a board, because sometimes it?s not necessary made the board replacement.

Dear sevillaf, I mentioned that no problem in line rate of TDX and ND2 in point 1 & 2 of my post.  Support website provides solution that applicable most of the time. Since in my case, solution is different , thats why I shared with you. Another fact that if line rate was not OK, then problem will be never solved after changing any board(ND2, TDX or XCS). If you have still any query, I will be happy to reply.