Finding the cable between 2 switches...

[Homercidal]

Ok, so I'm replacing a few switches with some POE switches to support our upcoming telephone upgrade.

I got a Cisco 24-port out on the shop floor with a bazillion wires. About 8-12 of them are connected to something.

In the server closet I have a 48-port Cisco switch.

I can't tell which cable is running where! The person who originally wired up the devices didn't ID the cables.

I *could* wait until everyone is gone for the day and power down their machines until I only have 1-2 connected cables, but I'd rather not stay after.

Is there a way to know which MAC address that 24-port switch has and then look that mac address up on the 48-port switch's address table?

 

[Homercidal]

Well, never mind. I figured it out.

I telnetted into the Main switch and listed the mac address and corresponding port. Now I only have to do the same at the other switch to know which cable is the one that runs back to the main switch.

The main switch is in a cabinet and not easy to get to the MAC address, but I can find it's MAC by scanning it's IP. Then take a laptop out to the shop switch and look up that mac in it's table.

Now is a good time to start labeling all of these cables.

 

[lustreking]

show cdp neighbors

should show you the hostname of connected switches, and which port they're connected to

 

[banesong]

Well, never mind. I figured it out.

I telnetted into the Main switch and listed the mac address and corresponding port. Now I only have to do the same at the other switch to know which cable is the one that runs back to the main switch.

The main switch is in a cabinet and not easy to get to the MAC address, but I can find it's MAC by scanning it's IP. Then take a laptop out to the shop switch and look up that mac in it's table.

Now is a good time to start labeling all of these cables.

Shouldn't you be able to show run or show chassis and get the mac via terminal?

 

[Homercidal]

Shouldn't you be able to show run or show chassis and get the mac via terminal?

I'm not terribly familiar with smart switches. It only crossed my mind that I could perform some router commands and get results.

And the Main switch was an HP Procurve. I forgot I hadn't replaced that with the Cisco yet.

Nevertheless it was really easy to log into each device and get the MAC address and Port numbers once I knew the MAC of one of them.

It was a good reminder to set up the security on them all too.