F3726, F3211, F3174, R5135, R3816-HP Firewalls and UTM Devices Network Management Configuration Guide-6PW100

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Figure 179 Traffic policing
Traffic policing is widely used in policing traffic entering the networks of ISPs. It can classify the policed
traffic and take predefined policing actions on each packet depending on the evaluation result, for
example:
• Forwarding the packet if the evaluation result is "conforming."
• Dropping the packet if the evaluation result is "excess."
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Line rate
Line rate also uses token buckets to evaluate traffic specifications for traffic control. The line rate of a
physical interface specifies the maximum rate for forwarding packets (including critical packets).
Compared with traffic policing, line rate can only limit traffic rate on a physical interface. To limit the rate
of all the packets on an interface as a whole, using line rate is easier.
For more information about token buckets, see "
2491HTraffic evaluation and token buckets."
With line rate configured on an interface, all packets to be sent through the interface are firstly handled
by the token bucket at line rate. If the token bucket has enough tokens, packets can be forwarded.
Otherwise, packets are put into QoS queues for congestion management. In this way, the traffic passing
the physical interface is controlled.