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Spee and duplex configuration

I need any recomendation interconnecting lan switches to server, what is the recomendation about the speed and duplex?, is better force this parameters or auto mode?

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Community Member

Re: Spee and duplex configuration

Usually forcing speed and duplex both on the switch and on the server is the way to go.

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Re: Spee and duplex configuration

Rule of thumb I am using.

Force duplex and speed (both sides) settings when switch is a 10/100/100Base (aka Triple speed) but server is a DUAL speed. This is also true when your server is triple speed and the switch is only dual.

Autonegotiate when switch and server is Triple speed.

Hope this helps.

Re: Spee and duplex configuration

For devices that have static IP Address and in fixed location (specially critical devices like routers, firewall, servers, etc), I hardcode the speed/duplex. Except for those devices that don't support hardcoding the speed/duplex (e.g. GE interface of non-Cisco devices like PacketShaper, HP Unix).

From what I understand in the past, there is no standard for auto-negotiation thats why every vendor set their own standards for auto-negotiation. Do take note that this is in the past.

I have experienced that devices from same vendor configured in auto-negotiation even using good quality cable experiences speed/duplex mismatch overtime or during maintenance (IOS/OS upgrade, System Reboot). You will be surprised that I experienced that between a Cisco Catalyst Switch and Router after two years in production and nobody touch them, suddenly they have a duplex mismatch :).

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