Strange network (switch connection) issue

[Fat Tone]

Hi

My office has grown from one to two to three units. Each time we have grown I have installed an additional identical switch and connected it back to the first. The switches are Cisco SG 100-24 (24 port Gb, unmanaged).

The first switch worked flawlessly for a couple of years.

When I added the second switch, all worked flawlessly for a couple of years.

When I added the third switch I started to get problems with it after being used a while. When I first connected it (via cable from switch to local patch-panel, via a patch in the service duct, to the new patch panel to the new switch), the port lit-up immediately and all was well. After a while the port light went out. I tried other ports and swapping cables etc and nothing worked. The only thing that worked was swapping the switch (just a little 8-port Netgear as a temporary switch).

So I had the switch swapped out and all was well for 3 weeks. Now it has failed again in exactly the same way, and I am back on the little Netgear switch while I puzzle this out.

The only things connected to the new switch are a couple of printers and half a dozen laptops.

Grateful for any suggestions!

Thanks

Tony.

[SteveC]

It'll take ages, but maybe leave the old faithful Netgear in alongside the Cisco and move one device at a time, say one device every couple weeks until it breaks?

Or get a managed switch and monitor the ports for errors?

[Fat Tone]

Thanks Steve, and welcome back to murc, good to see you around here again.

Sounds like a suspicion that there's some dodgy traffic causing the issue? I'll give your first suggestion a go intially, although there is a slight confound in that the Netgear is usually in use on a desk within the room and all the devices were in use before we added the 3rd unit. I'll also look in to my options for inspecting traffic.

Cheers

T.

[UtwigMU]

Could you get one big fancy 24 or 48 port switch from HP or Cisco and run everything from patch panel?

Also some cables, ports, ... can be damaged, try different cables or repunching ports / redoing cable terminations.