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New Member

excessive collision

hi guys:

we are currently encountering excessive collision as reported by our cisco 3640 router.

we do some changes on the network. replacing all hubs with switches, done already. portion of the clients that still been using 10mbps nic are replace with 10/100mbps nic, others will be replace when stocks of 10/100mbps nic arrive.

after this changes, we still encoutered excessive collission.

we plan on implementing aggregation switches to increase our backbone bandwidth, currently we use cross-connect uplink of 100mbps.

any suggestion.


Re: excessive collision

where are you experiencing the Excessive collisions ? on the router connection to the switch on the switch ports attached to the clients ?


Re: excessive collision

yes... but other like servers do not or can manage the excessive collision.

as/400 are also affected by this.


Re: excessive collision

Please Clarify where are collisions occurring ?

1. The port that goes from the router to switch

2. port from switch to clients ?

Re: excessive collision


it could be because there is a mismatch about the speed and the mode of transmision.The autonegotiation doesn't work well.

To avoid this situation, you can set the interface of ther router to 100Mbps and full duplex, and the same in the port of the switch.


New Member

Re: excessive collision

What is your acceptable error rate? It varies as you

would expect. It can range from 5% to 10%. There may also be a NIC card in the network that is creaing this problem. May be your NIC card is set to auto-negotiate. Auto-negotiation settings - quite often does not work very well with the upstream router

and your box auto-negotiates itself into inferior setting in broadcastmode