Re: Error

[Geert Jan de Groot <GeertJan.deGroot at xs4all.nl>]

>> This is an output I get off my 2611 router when I do a show log. Does
>> anybody Know what this means. 
>> The eth0/0 interface is plugged into a catalyst 2950 switch.
>> 
>> *Mar 30 23:37:15.174 UTC: %AMDP2_FE-5-LATECOLL: Ethernet0/0 transmit error
>> *Mar 30 23:37:15.294 UTC: %AMDP2_FE-5-LATECOLL: Ethernet0/0 transmit error
>> *Mar 30 23:37:15.366 UTC: %AMDP2_FE-5-LATECOLL: Ethernet0/0 transmit error
>> *Mar 30 23:37:15.386 UTC: %AMDP2_FE-5-LATECOLL: Ethernet0/0 transmit error

> Looks like collisions on your router and switch interfaces.

I'd like to elaborate on this a bit.
Ethernet is designed in such a way that on a proper designed network,
collisions happen in the first 64 bytes of a packet.
The transmission time of these first 64 bytes limit the size of
an ethernet (they limit the number of hubs etc because of the
propagation delay).

A 'late' collision happens outside the 64 byte-window.
This can happen if:
- There is a network design problem, like daisychaining too many hubs
- There is a half/full duplex mismatch between the switch and the router;
  the one set to full duplex will start transmitting when it wants,
  which typically can be outside the collision window.

With Mark I agree that it's probably a FDX/HDX mismatch that's 
causing your trouble. I just thought I'd provide some more
explaination for the curious.

Geert Jan


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