3com 3031 Instruccion De Instalación
Traffic Policing and Traffic Shaping
937
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CIR (Committed Information Rate)
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CBS (Committed Burst Size)
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EBS (Excess Burst Size)
It uses two Token Buckets with the token-putting rate of every bucket set as CIR
equally, but with different capabilities: CBS and EBS (CBS < EBS, called C Bucket
and E Bucket), which represents different bursting class permitted. In each
evaluation, you may use different traffic control policies for different situations,
such as: "C bucket has enough tokens”; "Tokens of C bucket are deficient, but
those of E bucket are enough”; "Tokens of C bucket and E bucket are all
deficient”.
equally, but with different capabilities: CBS and EBS (CBS < EBS, called C Bucket
and E Bucket), which represents different bursting class permitted. In each
evaluation, you may use different traffic control policies for different situations,
such as: "C bucket has enough tokens”; "Tokens of C bucket are deficient, but
those of E bucket are enough”; "Tokens of C bucket and E bucket are all
deficient”.
Traffic Policing
Typically, traffic policing is used to monitor the specification of certain traffic
entering the network and keep it within a reasonable bound, or it will make
“penalty” on the exceeding traffic so as to protect network resources and profits
of carriers. For example, it can restrict HTTP packets to occupy network bandwidth
of no more than 50%. Once finding the traffic of a connection exceeds, it may
drop the packets or reset the precedence of packets.
entering the network and keep it within a reasonable bound, or it will make
“penalty” on the exceeding traffic so as to protect network resources and profits
of carriers. For example, it can restrict HTTP packets to occupy network bandwidth
of no more than 50%. Once finding the traffic of a connection exceeds, it may
drop the packets or reset the precedence of packets.
Traffic Policing (TP) is widely used by ISP to police the network traffic. TP also
includes the traffic classification service for the policed traffic, and depending
upon the different evaluation results, it will implement the pre-configured policing
actions, which are described as the following:
includes the traffic classification service for the policed traffic, and depending
upon the different evaluation results, it will implement the pre-configured policing
actions, which are described as the following:
Forward: For example, continue to forward the packets evaluated as “conform”,
or re-forward the service marked DSCP by Diff-Server.
or re-forward the service marked DSCP by Diff-Server.
Drop: for example, dropping the packets evaluated as “not conform”.
Reset precedence and forward: For example, for packets evaluated “partly
conform”, to sign another priority then forwards them.
conform”, to sign another priority then forwards them.
Enter the policing of the next level: Traffic policing can stack gradually with each
class caring and policing more specific objects.
class caring and policing more specific objects.
Traffic Shaping
Traffic shaping is an active way to adjust the traffic output rate. A typical
application is to control the output traffic with TP index based upon downstream
network nodes.
application is to control the output traffic with TP index based upon downstream
network nodes.
The main difference between traffic shaping and traffic policing is that the packets
to be dropped in traffic policing will be stored during traffic shaping - generally
they will be put into buffer or queues (also called Generic Traffic Shaping-GTS, see
Figure 229). Once there are enough tokens in Token Bucket, those stored packets
will be evenly sent out. Another difference is that traffic shaping may intensify
delay, yet traffic policing seldom does so.
to be dropped in traffic policing will be stored during traffic shaping - generally
they will be put into buffer or queues (also called Generic Traffic Shaping-GTS, see
Figure 229). Once there are enough tokens in Token Bucket, those stored packets
will be evenly sent out. Another difference is that traffic shaping may intensify
delay, yet traffic policing seldom does so.