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Notable Replies

  1. Hi Muhammad,

    Policing is typically implemented by ISPs to limit the traffic of their customers so it will depend on the traffic contract that they sell you.

    The single rate two color policer might be a bit unfair since it doesn't allow bursting. With a CIR of 128kbps then you'll only be able to reach 128kbps if you keep sending traffic non-stop.

    The single rate three color policer allows bursting. Since data traffic is "bursty" by nature, this is probably a bit more fair to use. When your connection is idle, you can accumulate up to the Be and spend your Bc+Be when required.

    The Dual rate three-color policer is useful when the ISP is selling more bandwidth than they actually can offer. It's very unlikely that all customers are sending at maximum capacity all the time so they can offer you a "dual rate" contract. You might pay for a CIR of 128kbps and go up to 256kbps when the network is underutilized.


  2. Hi Davis,
    How Be is calculated depends on what type of policer is being used.

    Single Rate, Two Color Policer
    Bc = CIR/32
    Be = 0

    Single Rate, Three Color Policer
    Bc = CIR/32
    Be = Bc

    Two Rate, Three Color Policer
    Bc = CIR/32
    Be = PIR/32 (Peak Information Rate)
  3. Hi Rawa,

    I answered the first question a bit above this post.

    Here's a configuration example for all types btw:

    Policing Configuration Example

    The dual-rate three-color policer will always check both buckets. It will try to take tokens from both buckets, if possible then the traffic is conforming. If the BC bucket is empty but the PIR bucket still has tokens then the traffic is exceeding. Keep in mind the PIR bucket is larger than the BC bucket.


  4. Hi Andrew,

    I still have some doubt

    Let say BC = the total token can be store, if let say the police cir 128kbps, and by default bc=cir/32 which is 4000 bytes.

    and every second refilled the token 128000/8 = 16000 bytes, but the BC is only can fill up max 4000 bytes?

    Then how the user can get 128kbps if the BC token(4000 bytes) is less than the CIR (16000 bytes)?


  5. Hi Rene,

    What will be the MAX Bucket size (Bc & Be Bucket) for CIR 128Kbps and how we will calculate it ? If Bucket size(Bc) full then rest will end up with Be Bucket , right ?? If I configure 1-3c with CIR 128Kbps. So, there are two Bucket Bc and Be . what will happend if 256kbps traffic come in a sec . My understanding is , 128kbps traffic will meet Bc as Conform and rest 128kbps will meet Be as a Exceeding and execute accordingly as per action . Need your assistant badly to understand it clearly .Thanks


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