6509 is constantly arping, arp is the majority of trafic, and does this over and over for the same address's. Could the mac table be over loaded and is there a fix for this???
What is the source address? Is the MSFCs VLAN interfaces? If it is, check for any STP TCNs coming into the root switch for that VLAN. A STP TCN will clear the CAM table as well cause the MSFC to re-arp. The following page should help in locating TCNs
