- [Instructor] Let's briefly talk about
software defined networking.
Software defined networking, or SDN,
is a type of centralized network management
that is dynamic and programmable.
It separates the data that is transmitted
by network devices from the administration of those devices.
This can be helpful in a network
that has many switches and routers.
SDN is used to aid with traffic engineering,
routing, switching, monitoring,
load balancing, and security.
In a network that uses SDN,
there is a separate system known as a controller,
and this talks to all the routers and switches
and other network devices.
The SDN is broken down into two sections,
the data plane and the control plane.
The data plane is this black arrow that you see here,
and that is where the packets are flowing through,
and flowing through the various network devices.
Switches, routers, and so on.
Those packets can be manipulated by the SDN controller.
And the SDN controller does this
by way of the control plane.
These dotted lines represent the control plane
to each of these network devices.
This could be done on a separate network
and it allows for the separation of data and administration.
Ultimately, the SDN approach
deals less with individual protocols on individual devices
and more with the SDN controller's instructions
that are sent to those devices.
The controller tells routers and switches what to do
with particular types of packets,
applying rules as set by the admin of that controller.
So the administrator of the controller sets the rules.
For example, an admin might set a rule
for a switch that has a specific IP address.
Perhaps this switch over here
has the IP address 10.0.0.1.
This is known as a match.
And the admin on that SDN controller
might state that there is a rule
saying that this switch should drop
a certain type of packet.
So, maybe it says drop all ICMP packets.
So any types of ping commands, ICMP echoes or replies,
are gonna be dropped from that particular switch.
So the rule specifies that certain packets are dropped.
This is the action taken.
And this eliminates that type of packet from being forwarded
by that switch.
You can also use SDN software to more efficiently control
large numbers of virtual machines,
and categorize them within virtual LANs,
allowing them to be grouped and administered easily
even if they're physically moved.
And this makes the network more agile.
The most commonly known SDN protocol
is the open flow protocol,
which is open source, meaning anyone can use it,
although companies such as Cisco have entered the market
with their own proprietary SDN solutions.
Remember that in SDN, there is a controller,
a server or a virtual machine, or perhaps a container,
and that controller manages your various network devices,
routers, switches, and so on.
Know also that there is a control plane
and that is the network connections for the management
of those network devices to and from the SDN controller.
And then the actual data plane,
which is where the actual packets of data are being sent.
All the other data on the network.
And ultimately the SDN allows for the efficient transmission
of data packets.