I have a 5406zl connected to a 3400cl via a 10Gb CX4 cable.
The cable is 15m long.
On the 5406zl, everything seems fine.
On the 3400cl, I'm getting quite a few errors.
The most common error is "loss of link - Lost connection to multiple devices on port 49"
Then the next error I get is "Excessive CRC/Alignment Errors - Excessive CRC/Alignment Errors on port 49"
and "Excessive broadcasts - Excessive broadcast detected on port 49"
Port 49 on the 3400cl goes to port F4 on the 5406zl.
The 5406zl doesn't report any errors.