HP 2530 Switches: 20 seconds delay before a link comes up

[AlexGr]

Hi,
I’ve just received a couple of HP 2530 series switches and I’ve noticed that it takes about 20 seconds between plugging in a device and the link going up. I’ve finally found a fix for that, by setting the speed-duplex setting of the port manually to 100-full, since the building I’m working in uses cable-sharing (i.e. 2x 100 Mbit/s ports over 1 ethernet cable).

Is there a reason why the auto speed-duplex takes so long the find the correct setting?

With best regards
Alex

[TerjeAFK]

The delay can also be caused by Spanning Tree doing a full detect on the port to determine if the connected equipment is a switch or an endpoint and calculating possible loops in your network.

Check if Spanning Tree is enabled by running the command 'show spanning-tree'

If STP is enabled you can shorten the time it takes for the port to come up by using the command 'spanning-tree 1-24 admin-edge-port'

This will tell the switch that port 1-24 is connected to endpoints (computers, servers etc) and will bring those ports up faster.

If you do this I would also recommend that you enable BPDU protection on those ports to prevent loops if a switch should be connected by mistake: 'spanning-tree 1-24 bpdu-filter bpdu-protection'

[AlexGr]

Hi,
thank you for your response.

Neither setting the affected ports to edge ports nor disabling STP complete changed anything.

With best regards

[Richard Brodie_1 · Accepted solution]

It probably negotiates Gigabit, then discovers that doesn't work because your wiring is defective and falls back. I may be wrong but I think as far as the standard is concerned, you're lucky it works at all. Might I suggest auto-100 rather than fixed 100-FD. though? Manually seleting FD is likely to cause duplex mismatches unless you set it on both ends of the link.

[AlexGr]

Hi,

thank you for your response. I also thought that the cable sharing thing is probably the issue here, unfortunately I can’t change that easily, since it would require me to run new cables thought the entire building. Anyway it seems to work by setting it manually.

Thank you too for the hint with the duplex setting. I’ll keep that in mind, but I will leave it the way it is now since it works and the clients should default to full duplex anyway and if the two ends can’t establish a full duplex connection then I guess it’s better if they don’t work at all because the affected clients aren’t that important and at least I’ll notice it that way :)