3com S7906E 설치 설명서

 

4-2 

One evaluation is performed on each arriving packet. In each evaluation, if the number of tokens in the 

bucket is enough, the traffic conforms to the specification and the corresponding tokens for forwarding 

the packet are taken away; if the number of tokens in the bucket is not enough, it means that too many 

tokens have been used and the traffic is excessive. 

You can set two token buckets (referred to as the C bucket and E bucket respectively) in order to 

evaluate more complicated conditions and implement more flexible regulation policies. For example, 

traffic policing uses four parameters: 

z 

CIR: Rate at which tokens are put into the C bucket, that is, the average packet transmission or 

forwarding rate allowed by the C bucket.  

z 

CBS: Size of the C bucket, that is, transient burst of traffic that the C bucket can forward.  

z 

Peak information rate (PIR): Rate at which tokens are put into the E bucket, that is, the average 

packet transmission or forwarding rate allowed by the E bucket. 

z 

Excess burst size (EBS): Size of the E bucket, that is, transient burst of traffic that the E bucket can 

forward.  

CBS and EBS are carried by two different token buckets. In each evaluation, packets are measured 

against the buckets:  

z 

If the C bucket has enough tokens, packets are colored green.  

z 

If the C bucket does not have enough tokens but the E bucket has enough tokens, packets are 

colored yellow.  

z 

If neither the C bucket nor the E bucket has sufficient tokens, packets are colored red.  

 

Traffic policing supports policing traffic in the inbound direction and the outbound direction. Thereafter, 

the outbound direction is taken for example.  

 

The typical application of traffic policing is to supervise the specification of certain traffic entering a 

network and limit it within a reasonable range, or to "discipline" the extra traffic. In this way, the network 

resources and the interests of the carrier are protected. For example, you can limit bandwidth 

consumption of HTTP packets to less than 50% of the total. If the traffic of a certain session exceeds 

the limit, traffic policing can drop the packets or reset the IP precedence of the packets.