The port will drop to half-duplex, if retraining is enabled, and it doesn't get an auto-negotiation reply from the partner. If this used to work correctly, I'd swap out the network cable first thing.
Thanks for the Reply Dan ,
Swapping the cables does not seem to solve the problem permanently .Can the port retraining if disabled , will solve this ? will that work because , I see the retarining as a feature to the port to fall back to the minimal settings to retain the link .
Please let know .
Yes, you can disable auto-negotiation. Make sure to do it on both ends of the link, though.