Once traffic is identified it can be treated in a number of different ways.
You could as an example give it a minimum amount of bandwidth.
You could give it a maximum amount of bandwidth or a limit on the amount of bandwidth that it can send
some queuing mechanisms provide a minimum bandwidth guarantee policing and shaping the limit the amount
of traffic that you can transmit.
So polices and shapers are both great limiters but they differ in how they treat excess traffic as a
general rule of thumb.
Polices will drop excess traffic with traffic shapers will delay excess traffic.
In this example we've got traffic sent at different rates and administrator has configured a maximum
limit.
However as shown by this line here with policing any excess traffic is automatically dropped.
So polices will perform checks for traffic violations against a configured rate set by an administrator
which could be you to action that a police takes in response to traffic would either be dropping the
traffic as shown here or it could remark excess traffic and still transmit the traffic.
There are different options you could just transmit the traffic as long as you are below the threshold.
You could configure a police search or send the traffic without any modification as long as it's below
the configured threshold when it goes above the configured threshold.
You could read market but still transmit it and that would be true for traffic between the threshold
and a second threshold but any traffic exceeding the second threshold would be dropped.
We have this concept of a tri color or three color implementation when traffic is below the first threshold
it's transmitted as normal when it exceeds the first threshold but it's below a second threshold.
It will be remarked to our lower class.
So in other words you are moved from first class to economy as an example but to the traffic is still
transmitted.
And when you go above the second threshold you are simply kicked off the plane or in a data network.
The traffic has dropped.
What's important to understand about polices is that they do not delay traffic.
They will check the traffic and either remarketing and transmit it or drop it.
They do not buffer or delay traffic shapers on the other hand will delay traffic.
So they try and smooth traffic out by buffering it.
So if we look at our original traffic when it's shaped notice the curve.
Here is a lot smoother as the traffic is delayed so that it falls within a configured bitrate so the
shape doesn't drop the traffic but smooth it out by delaying the traffic to make sure that over a period
of time the traffic falls within a configured bitrate shape as are usually used to meet service level
agreements when the traffic spikes above the contracted rate.
The excess traffic is buffered and is delayed until it falls below the contracted rate.
Polices are a lot harsher.
They will drop as effective way as a shaper will try and smooth the traffic out over a period of time
to get it below a configured rate.