Two cisco gigabit switches refuse to link to each other. Any idea why?

Posted by Prody on Server Fault See other posts from Server Fault or by Prody
Published on 2010-12-14T22:00:59Z Indexed on 2010/12/22 13:56 UTC
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I have 3 Linksys SR2024 switches which are basically non-managed 24 port Gbit + 2 miniGBIC.

I now had to add another switch to the network, and my provider didn't have the SR2024 switch anymore, so I got the Cisco SLM2024 which was a bit more expensive. It's pretty much the same thing but with management (that I don't need).

So I've connected the SLM2024 to a SR2024 via Cat6 cable, and for some strange reason, I get no link.

If I connect any machine with a Gbit NIC to both switches, it links with 1Gbit autonegotiated. If I connect the SLM2024 to a non-Gbit switch (I have a cheap 4port ASUS switch), it will link just fine on 100Mbit full duplex.

Since the SLM2024 has management, I've tried to see if something is misconfigured on it's side, but it's not, it advertises 1Gbit and lower. (hence the machines connecting succesfully at 1Gbit).

Since the SR2024 that I'm trying to connect it to also connects successfully with another SR2024 and other Gbit machines, it means that it advertises Gbit too.

But for some reason when I link the SR2024 to the SLM2024 I get no link.

Please note that I've properly tested the wire.

Does anyone have any idea what's wrong?

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