The collisions counter counts the number of frames for which one or more collisions occurred when trying to send them. An example of this could be because another station was added to the network. As a conclusion, the collisions counter doesn't provide a very useful statistic when it comes to analyzing network performance or problems. When a collision is detected by a station after it has sent the 512th bit of its frame, this is counted as a late collision . The exact error message depends on the platform.
Possible causes are usually incorrect cabling or a non-compliant number of hubs in the network.
Excessive Collisions As discussed before, the maximum number of retries in the backoff algorithm is set to 16. This means that if an interface fails to allocate a slot in which it can transmit its frame without another collision for 16 times, it gives up. The frame is simply not transmitted, and is marked as an excessive collision . The maximum count is fifteen. However, if a Retry Error occurs, the count rolls over to zero.