[c-nsp] Cisco 6509-E QoS Policy Confusion

[Craig Allen]

Hello,
 
I have recently taken over a network and have a question about a current QoS policy and am trying to understand why it would have been configured this way.
 
An excerpt of the questionable config is as follows:
 
policy-map apply_1000_qos_for_att_dscp_to_nextlevel
  class EF_QOS_PORTS
   police cir 4000000000 bc 3125000 be 31250000 conform-action set-dscp-transmit ef exceed-action policed-dscp-transmit violate-action policed-dscp-transmit
  class af31_QOS_PORTS
   police cir 4000000000 bc 31250000 be 31250000 conform-action set-dscp-transmit af31 exceed-action policed-dscp-transmit violate-action policed-dscp-transmit
  class af21_QOS_PORTS
   police cir 1000000000 bc 31250000 be 31250000 conform-action set-dscp-transmit af21 exceed-action policed-dscp-transmit violate-action policed-dscp-transmit
!
 
The above policy has been applied to all Gig interfaces on the 6509 blades.
 
What I'm trying to understand is the CIR / BC / BE settings and exactly what they will achieve.
 
My first initial thought is that the CIR/BC/BE settings will achieve nothing?
 
Thanks!
 
Craig