H3C Technologies H3C S10500 Series Switches - Manual (Page 43)

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• CIR: Rate at which tokens are put into bucket C. It sets the average packet transmission or
forwarding rate allowed by bucket C.
• CBS: Size of bucket C, which specifies the transient burst of traffic that bucket C can forward.
• Peak information rate (PIR): Rate at which tokens are put into bucket E, which specifies the average
packet transmission or forwarding rate allowed by bucket E.
• Excess burst size (EBS): Size of bucket E, which specifies the transient burst of traffic that bucket E
can forward.
CBS is implemented with bucket C, and EBS with bucket E. In each evaluation, packets are measured
against the following bucket scenarios:
• If bucket C has enough tokens, packets are colored green.
• If bucket C does not have enough tokens but bucket E has enough tokens, packets are colored
yellow.
• If neither bucket C nor bucket E has sufficient tokens, packets are colored red.
Traffic policing
NOTE:
Traffic policing supports policing the inbound traffic and the outbound traffic. The outbound traffic is taken
for example.
A 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 for 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.
Figure 9 Schematic diagram for traffic policing
Token
bucket
Packets dropped
Packet
classification
Packets to be sent
through this interface
Packets sent
Tokens are put into the
bucket at the set rate
Queue
Traffic policing is widely used in policing traffic entering the networks of internet service providers (ISPs).
It can classify the policed traffic and take pre-defined policing actions on each packet depending on the
evaluation result:
• Forwarding the packet if the evaluation result is “conforming”