Instructor: Let's move into software-defined networking
or SDN.
Software-defined networking is a network architecture
approach that enables the network to intelligently
and centrally be controlled, or programmed,
using software applications.
This helps operators manage the entire network consistently
and holistically,
regardless of the underlying network technology.
Essentially, we're going to take our physical networks
and we can completely virtualize them,
or create a layer of abstraction
between the physical devices and the logical architecture
that they're going to represent.
Now with software-defined networking
we can create complex networks very quickly and easily,
leveraging increased network size and expanding their scope,
as well as their ability to rapidly change.
In fact, one of the great things
about software-defined networks is that they can be changed
automatically by the network itself
using automation and orchestration.
On the other hand, all this rapid change does make it harder
for us, as humans, to keep up with it,
and fully understand the data flows on our network
at any given time.
Now, when it comes to software-defined networking,
there are several pieces that we need to consider
including the application layer, the control layer,
the infrastructure layer, and the management plane.
These three layers are going to allow the network
to be decoupled from the underlying hardware itself.
The application layer is going to focus
on the communication resource requests
or information about the network as a whole.
The control layer is then going to use that information
from the applications and decide how to route a data packet
on that network.
It also makes decisions
about how traffic should be prioritized,
how it should be secured,
and where it should be forwarded to.
The infrastructure layer is going to contain
the actual networking devices that receive the information
from the control layer about where to move the data,
and then it's going to perform those movements.
Now, with software-defined networking,
these underlying infrastructure devices
can be physical or virtual devices
depending on your network configuration,
or a combination or hybrid of the two.
Remember, the whole concept with software-defined networking
is spread this layer of abstraction
between the real underlying devices
and the control and data flow
that's going to happen on that network.
Software-defined networking is also critical for use
in our successful cloud applications,
because it gives us the scalability and elasticity
and agility that we need inside those networks.
Now, the fourth part of software-defined networks
is our management plane.
Now the management plane is going to be used
to monitor traffic conditions and the status of the network.
Basically, the management plane is going to allow us
to oversee the network and gain insight into its operations.
This will also allow us to make configuration changes,
to set things up the way we want,
and make sure they're working the way we need them to.
So, for the exam I want you to remember
that software-defined networking, or SDN,
is broken down into four parts:
the application layer, the control layer,
the infrastructure layer, and the management plane.