The control plane is the part of a network that carries signaling traffic and is responsible for routing.
The data plane (sometimes known as the
user plane, forwarding plane, carrier plane or bearer plane) is the part
of a network that carries user traffic.
Let's consider the example of the management of public transportation of a city.
Before we send bus drivers out, we need to have a plan.
Control Plane = Learning what we will do
Our
planning stage, which includes learning which paths the buses will
take, is similar to the control plane in the network. We haven't
picked up people yet, nor have we dropped them off, but we do know the
paths and stops due to our plan. The control plane is primarily about
the learning of routes.
In
a routed network, this planning and learning can be done through static
routes, where we train the router about remote networks, and how to get
there. We also can use dynamic routing protocols, like RIP, OSPF and
EIGRP to allow the routers to train each other regarding how to reach
remote networks. This is all the control plane.
Data Plane = Actualy moving the packets based on what we learned.
Now, after the routers know how to route for remote networks, along comes a customers packet and BAM! this is were the data plane begins. The data plane is the actual movement of the customers data packets over the transit path. (We learned the path to use in the control plane stage earlier).
