I'm experiencing a lot of Excessive Late Collisions on only one interface all the time. This is connected to a Cisco firewall. Anyone have any ideas why?
A local collision occurs when two or more nodes transmit at the same time. If two nodes collide on the other side of a repeater, the instrument counts this as a Remote Collision. Local Collisions and Remote Collisions are only reported at 10 Mbps.
On a 10BASE-T network, Excessive collisions are most often caused by a physical media problem such as missing or incorrect terminators, impedance discontinues (such as, defective connecters, cable stubs, crushed cables), or defective network interface cards.
In other words, I suspect that you have a 10Mbps hub in the middlw or replace the cable.
From my HP 4108 switch with only 10/100/1000Mbit/s ports one port is connected to a Cisco Firewall. The firewall is set to run 100Mbit/s full duplex. And also the HP port.
If the HP port really was configured for 100full it wouldn't report collisions, since they are not possible on a full duplex link. Late collisions on a switched TP link can only occur if there is a duplex mismatch, i.e. one side runs half duplex, the other side runs full duplex.
Please double check, that both ends of the link are configured for *fixed* 100Mbit/s full duplex and auto-negotiation is disabled.
In general, I think it's better to try *both* sides set to auto-negotiation first. Only in case this fails set *both* sides to the *same* fixed settings.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.