Problems setting speed and duplex

[scottyoung]

We have installed a 4510R router as well as a 3560 10/100 switch. When the speed and duplex are hard coded to 100 full on both switches the connection breaks. When set to auto on both ends, link stays up. Any help would be greatly appreciated.

[glen.grant]

Make sure you are using a crossover cable between the two , if you are using a straight thru and relying on mdix I believe this will break the connection if you hardcode the speed and duplex . Someone else can chime in if they have a different interpretation. If you have a crossover you can try disableing the mdix feature on both sides and see if you can hardcode.

[scottmac]

This could be a symptom of a bad or poorly terminated cable.

If you hard-code the speed to 10 and or the duplex to half, does it stay up?

If this is a handmade cable, try replacing it with a known-good commercial cable. If all you have available is hand-made cables, then verify that the pairs are p0inned-out according to the EIA/TIA standard (left-to-right, clip down:

Orange-white,

Orange,

Green-white,

BLUE,

White-blue,

Green,

White-brown,

Brown

*OR*

White-green,

Green,

White-orange,

BLUE,

White-blue,

Orange,

White-brown,

Brown

If your cables are not pinned-out according to the spec, the ACR (attenuation-to-crosstalk ratio) is blown and the cable cannot carry full-duplex high-speed traffic (or it might work, but not without a lot of errors .... which is why the interface will downshift to a slower speed or half duplex).

Good Luck

Scott

A router-switch connection should be a straight-through cable.