So where would you use polices and where would you use shapers.
Polices are generally used as ingress tools.
In other words the traffic has dropped before it's processed so that you don't waste valuable resources.
If a package is going to be dropped anyway you might as well drop it on the ingress or incoming interface
of a rider so that you don't waste valuable bandwidth and you cycles to move it from one interface to
another to a running lookup and so forth and then drop the packet.
Polices can be used on aggress to control the amount of traffic sent out of an interface but are generally
used to enforce a traffic policy on ingress as an example your service provider may have an ingress
police to ensure that you don't send too much traffic as an example you could have paid for 100 megabits
per second.
Internet link but the physical interface that connects you to your service provider could be Gigabit
Ethernet so to ensure that you don't transmit more than 100 megabits per second the service provider
on the ingress interface on the ISP side will implement a police to drop traffic that exceeds 100 megabits
per second when traffic is exceeded.
The police can either drop the traffic or remake the traffic.
The disadvantage of a police is that stopping traffic which results in TTP resets TTP is designed to
re transmit traffic that's been dropped.
So when a police is dropping a lot of traffic it causes a lot of TTP re transmissions or re sends polices
don't introduce chatter or delay because they simply drop the packet.
They don't delay it with shapers introduced delay and Jetta by slowing down packets or buffering them
for a period of time before transmitting them.
Shapers are a lot gentler than polices so generally they are deployed between an enterprise customer
and the service provider to ensure that you don't exceed the contracted rate again using the example
of a customer connected to a service provider via a gigabit interface.
The customer will slow itself down under the 100 megabits per second threshold to ensure that it doesn't
send traffic to the service provider who will simply drop the traffic shapers result in fewer TCB re
transmissions because they're not dropping the traffic they are delaying it or slowing the traffic down.
So in summary policing drops or remarks it doesn't buffer it causes TTP read transmissions it doesn't
introduce G2 and delay shapers don't drop traffic they delay the traffic but that can result in additional
delay or jitter shaping is a lot gentler on traffic.
Policing is very harsh causes re transmissions.