Vinoth,
Things you may want to first look into is access switch logs and core switches logs if any, look for flapping interfaces specially if you have dual uplink connections to a dual core switches, go over these links bellow
show log
show process cpu <-- flapping interfaces and/or bridging loops will also cause high cpu utilization, more details in bellow link.
See Identify the loop section in STP link
Troubleshooting STP
http://cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a0080136673.shtml
If you have an HSRP environment on your core switches and happened to see HSRP SSTANDBY-3-DUPADDR message logs most of time is due to STP configuration issues, this link will give you a more thorough perspective on these type of messages.
Troubleshooting HSRP Problems - STP
http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a0080094afd.shtml
Rgds
-Jorge
PLS rate any helpful post if it does!
Jorge Rodriguez
