From: Joseph D. Phillips (josephdphillips@fastmail.us)
Date: Sat Dec 04 2004 - 23:46:06 GMT-3
OK, how much do you charge to explain that in plain English?
Does anyone here know how to do this math? I can do FRTS, but not this...
Bob Sinclair wrote:
> Joseph,
>
> The lengthy quote below is the best discussion I have seen of this
> topic. Please check out the full link as well.
>
> quote:
> From:
> http://www.cisco.com/en/US/products/sw/iosswrel/ps1834/products_feature_guide09186a008008044c.html#1019822
>
>
> Token Bucket Algorithm with One Token Bucket
>
> The one token bucket algorithm is used when the violate-action option
> is not specified in the police command CLI.
>
> The conform bucket is initially set to the full size (the full size is
> the number of bytes specified as the normal burst size).
>
> When a packet of size B bytes arrives at time t the following actions
> occur:
>
> a. Tokens are updated in the conform bucket. If the previous arrival
> of the packet was at t1 and the current time is t, the bucket is
> updated with (t-t1) worth of bits based on the token arrival rate. The
> token arrival rate is calculated as follows:
>
> (time between packets<which is equal to t-t1> * policer rate)/8 bytes
>
> b. If the number of bytes in the conform bucket - B is greater than or
> equal to 0, the packet conforms and the conform action is taken on the
> packet. If the packet conforms, B bytes are removed from the conform
> bucket and the conform action is completed for the packet.
>
> c. If the number of bytes in the conform bucket - B is less than 0,
> the exceed action is taken.
>
> Token Bucket Algorithm with Two Token Buckets
>
> The two token bucket algorithm is used when the violate-action is
> specified in the police command CLI.
>
> The conform bucket is initially full (the full size is the number of
> bytes specified as the normal burst size).
>
> The exceed bucket is initially full (the full exceed bucket size is
> the number of bytes specified in the maximum burst size).
>
> The tokens for both the conform and exceed token buckets are updated
> based on the token arrival rate (or CIR).
>
> When a packet of size B bytes arrives at time t the following actions
> occur:
>
> a. Tokens are updated in the conform bucket. If the previous arrival
> of the packet was at t1 and the current arrival of the packet is at t,
> the bucket is updated with t-t1 worth of bits based on the token
> arrival rate. The refill tokens are placed in the conform bucket. If
> the tokens overflow the conform bucket, the overflow tokens are placed
> in the exceed bucket.
>
> The token arrival rate is calculated as follows:
>
> (time between packets<which is equal to t-t1> * policer rate)/8 bytes
>
> b. If the number of bytes in the conform bucket - B is greater than or
> equal to 0, the packet conforms and the conform action is taken on the
> packet. If the packet conforms, B bytes are removed from the conform
> bucket and the conform action is taken. The exceed bucket is
> unaffected in this scenario.
>
> c. If the number of bytes in the conform bucket - B is less than 0,
> the excess token bucket is checked for bytes by the packet. If the
> number of bytes in the exceed bucket - B is greater than or equal to
> 0, the exceed action is taken and B bytes are removed from the exceed
> token bucket. No bytes are removed from the conform bucket.
>
> d. If the number of bytes in the exceed bucket - B is less than 0, the
> packet violates and the violate action is taken. The action is
> complete for the packet.
>
> end quote,
>
> Hope that Helps
>
> Bob Sinclair
> CCIE #10427, CCSI 30427, CISSP
> www.netmasterclass.net
>
>
> ----- Original Message ----- From: "Joseph D. Phillips"
> <josephdphillips@fastmail.us>
> Cc: <ccielab@groupstudy.com>
> Sent: Saturday, December 04, 2004 2:37 PM
> Subject: Policing syntax
>
>
>> Could someone please explain to me the difference between
>> conform-action and exceed-action?
>>
>> QoS Class Police configuration commands:
>> conform-action action when rate is less than conform burst
>> exceed-action action when rate is within conform and conform +
>> exceed burst
>> violate-action action when rate is greater than conform + exceed burst
>>
>> The default is to drop packets within the range defined by
>> exceed-action, but it seems that this range defines a range that is
>> acceptable.
>>
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