Gigabit port problem on ProCurve 2650

[andypitts]

Hi everyone.

 

Part of our network consists of 2 HP ProCurve 2650 switches (one in our ICT suite on the 2nd floor and one in a "data cupboard" on the ground floor). The switches are connected via patch panels (i.e. not directly cabled).

 

The problem I've got is that we cannot get a Gigabit connection between the 2 switches. The 2nd floor switch has been patched to one if its gigabit ports but when I patch the other end to the gigabit port of the ground floor switch, I get no data passing through. When I use one of the standard 100mb ports on the ground floor switch, however, the switches do talk to each other. It sounded like a faulty port but I've tried a laptop plugged into the gigabit port on the ground floor switch and I get a connection...

 

Does anyone have any idea what might be causing this?

 

Thanks

[pete]

Check the ground > second floor cable runs with a cable tester.

 

Check the logs on both switches to see what occurs when you connect the two switches.

 

If the switches aren't in production yet, yank one and connect it to the other directly via a known good cable.

 

Ensure you aren't creating a loop (and a port is getting error-disabled somewhere) and check what spanning-trees default behaviour is set to if you're running it.

[Ste_Harve]

I've had similar that was caused by a faulty cable run between the patch panels, and have also had it where the patch panel wasn't terminted 100% correctly. Can you plug a laptop in to one end of the patch panel and other end into the gig ports on the switch and see if that works.

[DMcCoy]

CAT 5/5e? and don't forget the combined cable run may be too long for a 1Gb link.

[themightymrp]

Could be rare but try using a crossover cable, if the auto switching is turned off it won't connect (by default I think it is turned on though)

[Michael]

It could be one end is auto and the other end a forced speed (on the gigabit ports).

[Michael]

So long as you've tried a notebook on both switches (and they work) odds are it'll be a cabling problem at the patch panel level. Gigabit needs all 4 pairs of CAT5e or CAT6, whereas 10/100 needs 2 pairs.

[andypitts]

Thanks for all these suggestions, I'll work my way through and report back. The switches are already in production so I'll have to wait for the ICT suite to be free to do some testing. All the switch ports are set to Auto and the cabling should be CAT5e. I'd expect the cable run to be about 25m so well within the 100m max (according to Wikipedia).

[Destinova]

Also check the patch panel. I had a similar issue and the panel was only rated for Cat5, not 5e.

[andypitts]

So I checked all the patch panels and they were labelled CAT5e or GigaPlus so I guessed this was a good sign and the patch cables that I could see were all 5e. We also had a redundant cable run so I swapped one for the other but still got the same problem. Next I unplugged the patch cord from the 2nd floor switch and put it into a laptop (as @Ste_Harve suggested) - 1.0Gbps Ethernet connection! So it must be the Gigabit port on the 2nd floor switch... no - plugged the cable back into the switch and suddenly the whole room is back on the network. Both switches are now reporting 1000FDx connections on those ports. I can only assume that there was some slight connection problem with the switch port and the patch cord, something that would still allow 100Mbps data connections but fail completely when we tried to push 1Gbps through - maybe something to do with what @Michael said about Gigabit connections needing all 4 pairs. Hopefully this was just a one-off problem but at least if it recurrs I'll have a better idea about where the real problem lies. Thanks again for everyone's advice.