Understanding show policy-map interface xx

Question:

I need to understand the WS-C3750X-24P-S difference between "total drop" and "no-buffer drop" in the output:

Router#sh policy-map int gi 0/0
GigabitEthernet0/0


  Service-policy output: SHAPE-OUT


    Class-map: class-default (match-any)
      441790059 packets, 219164243756 bytes
      30 second offered rate 23718000 bps, drop rate 228000 bps
      Match: any
      Queueing
      queue limit 64 packets
     (queue depth/total drops/no-buffer drops) 0/3447160/0
      (pkts output/bytes output) 443857262/223879827364
      shape (average) cir 40000000, bc 160000, be 160000
      target shape rate 40000000

Answer:

You can have drops due to rasons below

1. WRED dropping the packet
2. You excceded the configured rate and you are buffering the packet and you have exceeded the configured queue limit.
3. You are exceeding the confgured rate, you are trying to buffer the packet. But you have not reached the configured queue limit, but there is no buffer available to allocate the configured queue-limit

Drops due to 3rd Reason will come as " no-buffer drops"
Drops due to all the above reasons, WS-C3750V2-24PS-S Price is Total drops

For futher information, please refer to  http://www.journalspace.com/index.php?do=/blog/3405/influencing-eigrp-path-over-tunnel-interfaces/