zaqtivi
When you perform show arp and you get something in the results that shows incomplete, this an indication that the router has sent the ARP request and has not received any response. In addition to checking cables I would suggest that you check to make sure that the interface where the device should be connected is in up/up state. If possible check to see if the device for which you are issueing the ARP is on line.
HTH
Rick
HTH
Rick
