Catalyst 6500/6000 Switch High CPU Utilization

On Catalyst 6500/6000 Switches, there are two CPUs. One CPU is the supervisor engine CPU, which is called the Network Management Processor (NMP) or the Switch Processor (SP). The other CPU is the Layer 3 routing engine CPU, which is called the MSFC or the Route Processor (RP).
The SP CPU performs functions that include:

• Assists in MAC address learning and aging
  Note: MAC address learning is also called path setup.
  
• Runs protocols and processes that provide network control
  Examples include Spanning Tree Protocol (STP), Cisco Discovery Protocol (CDP), VLAN Trunk Protocol (VTP), Dynamic Trunking Protocol (DTP), and Port Aggregation Protocol (PAgP).
  
• Handles network management traffic that is destined to the CPU of the switch
  Examples include Telnet, HTTP, and Simple Network Management Protocol (SNMP) traffic.
  

The RP CPU performs functions that include:

• Builds and updates the Layer 3 routing and Address Resolution Protocol (ARP) tables
  
• Generates the Cisco Express Forwarding (CEF) Forwarding Information Base (FIB) and adjacency tables, and downloads the tables into the Policy Feature Card (PFC)
  
• Handles network management traffic that is destined to the RP
  Examples include Telnet, HTTP, and SNMP traffic.
  
  
  Ref:http://www.cisco.com/en/US/products/hw/switches/ps708/products_tech_note09186a00804916e0.shtml