Cause of exceeding packet in policy-map?

Hi,

Just want to ask your thought about this, Even though traffic usage doesn't exceed/reach the allocated BW of 5Mbps, there a minimal increase on "Exceeded packets", What would be the cause of these increase?

Class class-default

police cir 5000000 bc 156250

conform-action set-mpls-exp-imposition-transmit 0

exceed-action drop

Class class-default

police cir 5000000 bc 156250

conform-action transmit

exceed-action drop

Service-policy output: POL-IN

Class-map: class-default (match-any)

44633733 packets, 12625980741 bytes

30 second offered rate 11000 bps, drop rate 0 bps

Match: any

police:

cir 5000000 bps, bc 156250 bytes

conformed 44584741 packets, 12599151611 bytes; actions:

set-mpls-exp-imposition-transmit 0

exceeded 13422 packets, 19648851 bytes; actions: <-------

drop

conformed 11000 bps, exceed 0 bps

Service-policy output: POL-OUT

Class-map: class-default (match-any)

61074304 packets, 57584593170 bytes

30 second offered rate 11000 bps, drop rate 0 bps

Match: any

police:

cir 5000000 bps, bc 156250 bytes

conformed 60389018 packets, 56586377242 bytes; actions:

transmit

exceeded 685096 packets, 998203914 bytes; actions: <-------

drop

Thank you