Is there an easy way to retrieve the link speed of network devices?

We have a mix of 100 and 1000mbps cabling in this office with cabling that ranges from ancient home-made cat5 to brand new cat6, and a mish-mash of semi-accessible switches and network segments that support various combinations of speed (some only have 1 or 2 gigabit ports, others have ports that, for whatever reason, no longer support gigabit, some might have a fast ethernet switch hanging off a gigabit port etc.).

I suspect that some devices that don't need gigabit are currently on it, and other which might benefit are stuck on fast ethernet. Short of pulling the whole thing to bits and doing a lot of testing I'm not sure how I'd check this though.

Obviously, if all were workstations or servers I could check them easily enough, but we have many devices which can't be queried or which don't reflect link speed on their network ports.

Is there are easy method to audit devices to find out which nodes are gigabit-capable?

Lunatik

Posted 2015-03-18T11:34:10.277

Reputation: 4 973

I think its hard to say without a complete topology of the site. If it was me I would start at the network device level and work backwards towards the switches. So say I had a Server hosting files I would log on to that Server and check to see if it has auto-negotiated at 1Gb or not. If it hasn't and would benefit from this then I would check the cabling to see what device could it be swapped with (maybe a printer or whatever is in the Gb port). – CharlesH – 2015-03-18T11:45:35.670

Just to add to this, I would make a list of all devices that would benefit from gigabit ethernet and check them all to see if they are running at gigabit speeds. If they are then you can wrap the issue up as no changes needed as no improvement will be seen. – CharlesH – 2015-03-18T11:46:58.780

Yes, the whole place is a bit of a mess and I am lucky enough to have inherited it. I'm just wondering if there are any network discovery tools that might automate or avoid at least some of the dusty and time-consuming manual activity. – Lunatik – 2015-03-18T12:12:27.293

Answers

Get a small switch that has different colour LEDs on the network ports depending on the speed of the link, go round connecting it to every device in turn and record what colour the light goes.

Mike Scott

Posted 2015-03-18T11:34:10.277

Reputation: 4 220

I had thought of that and may end up doing so, but this doesn't tell me if the cable (which will inevitably be unlabelled and may snake its way through conduits etc.) is damaged/poor spec and can't support gigabit but is connected to a gigabit port. – Lunatik – 2015-03-18T12:10:57.687

Sorry too long for a comment so will place here although more advise than an answer per say...

Putting myself in your shoes:

I would use Zenmap to run a network scan and figure out firstly what you have on the network.

It is quite good at giving makes and models so you can check on google to see if they have a gigabit NIC or not.

If you have any layer 3 switches you can do some clever stuff like checking MAC addresses on ports to see what device is plugged in where (zenmap will show you the MAC address too so you can cross reference it here) also check for packet drops which would indicate problematic cabling.

Make a excel spreadsheet or something and populate them so you can keep track for example: you find a device on zenmap, you google a make/model it has gigabit NIC, the auto-neg speed is only 100Mb, however it is plugged in to a gigabit port then you can likely guess its a dodgy/old cable. Make sense?

Dumb switches are going to be your headache as they provide no information whatsoever. This is where your going to have to get a little dirty and start to do more manual work like the suggestion above with another switch. I'm guessing whoever this is does not really want to dip in to its IT budget and replace the switches which would be the easiest option :)

CharlesH

Posted 2015-03-18T11:34:10.277

Reputation: 1 943

Thanks. I already run a network discovery tool (not Zenmap) and have a spreadsheet with the DHCP/static, MAC, physical location, login URL etc. so I'm at least part of the way there. Most of the switches are unmanaged cheapies thought so it looks like the old fashioned way or not at all. – Lunatik – 2015-03-18T13:26:10.203