Switch name

[kakomaisa]

Hi all! 

I have around 100 switch and I have IP phones connected to those switches, Iam having the IP address and MAC address of the phone and I need to know which switch is that phone connected to it.

When i login to L3 switch and type show arp | include ip address it immediately find the mac address which I already have but the opposite is not correct.

How can i Find the switch from those two information's .

[johnlloyd_13 · Accepted solution]

hi,

are you using cisco IP phones and CUCM/call manager?

you can check the switch and port information in CUCM/call manager.

search for the phone, i.e by device name (SEP+mac address format), description/text, DID number, etc.

click on the IP address link. look for the CDP info under network statistics > network.

[Joseph W. Doherty]

Possibly you misunderstand the nature of the ARP table.  Unlike the MAC table, which a switch uses to keep track of what port to send destination MACs to, the ARP table only is populated when the host (in this case the switch) communicates with another host at L3 (like if the switch pings an IP).

What might work, to populate the ARP table, is to, from each switch, ping the network broadcast IP for each VLAN the switch is connected to.

As others have noted, usually the MAC table has a much shorter timeout than the ARP table.  So it's possible, the ARP table may have MACs, still in it, not recently placed/refreshed in the MAC table.

[kakomaisa]

Hi Johnlloyd

Thank you very much for your reply, you saved my day.