There is really no easy way to discover the IP address of the device connected to a port.
1. If you can get the MAC address of the device by using the 'show mac-address-table' command. Once you have these, you can do:
- if the switch is a L3 switch, issue the command 'sh ip arp'or '"show ip arp | include "' to see if the MAC address is one that has been resolved recently. In that case, the IP address associated with that MAC address is the IP of the device connected to that port.
2. You can also download a freeware tool, ccgetmacaddress, with this tool you can get the IP to MAC or MAC to IP.