show mac-address-table

[SpaceHonkey]

Ah the old show mac-address-table command. And how it fails me on some of my Nortel switches.

Of course the idea here is simple, using this command - get the MAC of the device plugged into a port. Then on the router look at the arp table for the MAC, and viola - you have the IP of the device on that port.

On a few of our Nortel 5520s and 4548s, the command shows only the MACs in the native vlan. On others, it works as designed. As a workaround, I can specify the VLAN ID and it works, however going through each vlan won't be fun, especially since knowing it is apparently not working as it should.

Any ideas why this is the case?

 

[xphil3]

Ah the old show mac-address-table command. And how it fails me on some of my Nortel switches.

Of course the idea here is simple, using this command - get the MAC of the device plugged into a port. Then on the router look at the arp table for the MAC, and viola - you have the IP of the device on that port.

On a few of our Nortel 5520s and 4548s, the command shows only the MACs in the native vlan. On others, it works as designed. As a workaround, I can specify the VLAN ID and it works, however going through each vlan won't be fun, especially since knowing it is apparently not working as it should.

Any ideas why this is the case?

Sounds like a bug to me, if its that way be design thats terrible. You're generally supposed to have MAC, Port and VLAN fields. Thats what you get when you go with Nortel though... Give them a call and see if its that way by design.

As for a work around, script to log into the device and run the command and export the output to a text file. A simple *nix script could do this using expect. You could also store the information locally on whatever space you have and pull it down via ftp/tftp.

 

[SpaceHonkey]

When I get some time I plan on evaluating netdisco which does all the dirty work of querying the switches and putting them into a searchable database.

I haven't thoroughly compared the configs of the devices that do behave as expected vs. those that don't. I highly suspect the firmware versions are different, and I'm pretty much stuck there.

I would call Nortel but suprise, none of the devices are under contract.