Late Collision Error Messages

Late Collision Error Messages

%LANCE-5-LATECOLL: Unit [DEC], late collision error

%PQUICC-5-LATECOLL: Unit [DEC], late collision error

The slot time, 51.2 microseconds, used to detect and report collisions is based on the round trip time between the furthest points on the Ethernet link. The value is calculated by taking the smallest Ethernet frame size of 64 bytes and multiplying it by 8 bits, which gives 512 bits. This number is then multiplied by .1 microseconds. The farthest distance between the end points of the cable should be reached within half of this slot time, 25.6 microseconds.

Excessive collisions typically occur when too much traffic is on the wire or too many devices are in the collision domain. After the fifteenth retransmission plus the original attempt, the excessive collisions counter increments, and the packet gets dropped. In this case, too many devices are competing for the wire. In addition, duplex mismatches can also cause the problem. A syslog message is generated by the switch, as depicted in Example 1-2, when excessive collision occurs on the port.