3Com MSR 50 Series Configuration Manual page 1630

1630 C 84: T
HAPTER RAFFIC
C , P ,
LASSIFICATION OLICING AND
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.
Traffic policing allows you to define match rules based on IP precedence or
DiffServ code point (DSCP). It is widely used by ISP to police the network traffic. TP
also includes the traffic classification service for the policed traffics, and depending
upon the different evaluation results, it will implement the pre-configured policing
actions, which are described as the following:
Forwarding the packet whose evaluation result is "conforming".
■
Dropping the packets whose evaluation result is "nonconforming".
■
Modifying the precedence of the packets whose evaluation result is
■
"conforming" and forwarding them.
Modifying the precedence of the packets whose evaluation result is
■
"conforming" and entering the next-rank TP.
Entering the next-rank policing (TP can stack rank by rank, with each rank
■
policing more detailed 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.
The main difference between traffic shaping and traffic policing is: 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 Traffic Shaping - TS; see
Once there are enough tokens in Token Bucket, those stored packets will be evenly
sent. Another difference is that traffic shaping may intensify delay, yet traffic
policing seldom does so.
S
HAPING
Figure 460).