Collision on Fast Ethernet

Answered Question
Apr 9th, 2008
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Dear Experts,


I am getting the below log from one of the router.Can you pls suggest the steps to find the exact reason from where the collisions are generating.

1. Cabling is OK

2. We are not using HUBS on that location.

3. systems are also branded one (HP)


%PQUICC_FE-5-LATECOLL: PQUICC/FE(0/0), Late collision


regds

Correct Answer by Kevin Dorrell about 9 years 3 months ago

Normally, collisions are only seen in half-duplex situations. Normally they are nothing to worry about ... they are a normal part of the half-duplex contention protocol.


This is different. It is a late collision, which is an error.


The most likely explanation is that you have the switch acting half-duplex, and the HP configured as 100 full-duplex, a "duplex mismatch".


The most common cause of that is configuring the switch for auto duplex, and the HP as fixed full-duplex. The link should be either auto at both ends, or fixed config at both ends, but never a mix.


Kevin Dorrell

Luxembourg


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Correct Answer
Kevin Dorrell Wed, 04/09/2008 - 06:32
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Normally, collisions are only seen in half-duplex situations. Normally they are nothing to worry about ... they are a normal part of the half-duplex contention protocol.


This is different. It is a late collision, which is an error.


The most likely explanation is that you have the switch acting half-duplex, and the HP configured as 100 full-duplex, a "duplex mismatch".


The most common cause of that is configuring the switch for auto duplex, and the HP as fixed full-duplex. The link should be either auto at both ends, or fixed config at both ends, but never a mix.


Kevin Dorrell

Luxembourg


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