- [Narrator] Enterprise WAN connections
allow us to inter-connect main offices
with branch locations among other things,
and that allows us to share resources.
We can share access to centrally located
data, services or applications.
Traditionally, dedicated circuits have been used,
to achieve this connectivity.
Things such as frame relay or MPLS.
Although these provide reliability
and security for the connection,
our modern networks require some re-thinking of this.
Cloud usage as we know is on the rise.
So we need ways to simplify the management
of wide area networks.
We also need a way to include our cloud resources.
More and more enterprises are using cloud based storage.
And that's why SD-WAN is also on the rise.
SD-WAN stands for software-defined wide area network.
As the name suggests, this uses software to control,
and to manage the interactions
between branch locations and our central resources.
When we're looking at the function of SD-WAN,
one of the big advantages,
is that there's no longer the need
for backhauling your traffic.
And when we say backhauling your traffic,
we mean that historically with these dedicated circuits,
traffic would have to go from the branch,
back to the main site,
no matter what type of traffic it was.
Whether that was WAN internet traffic,
whether that was traffic destined for shared resources,
whatever that is, all of the traffic was backhauled
over that WAN connection to the main office.
So that offers the potential for saturation
of the WAN connection.
Instead, we want to look here at what SD-WAN allows us to do.
If we take a look at the very simplified topology,
we can see that we have a branch location,
connected over an MPLS circuit,
which is a traditional WAN connection method,
that's connected back to a data center.
At the data center,
we have some advanced security and inspection happening.
So that's why we would tunnel
all of our traffic from the branch,
back to the data center for inspection.
Now in this traditional WAN setup,
all of the traffic from the branch,
is backhauled to the data center
for those security services.
That includes traffic destined to the cloud,
or the public internet,
and traffic destined locally
within the organization as well.
So as we mentioned and as you can probably imagine,
this can cause a myriad of performance issues,
and delay.
Depending on your circuit speed,
it can cause some bandwidth issues on the MPLS connections.
SD-WAN addresses this by its ability to interact
with all kinds of cloud applications.
More and more our applications are going cloud-based.
Think of how cheap and easy AWS storage is now.
And how Office 365 has turned to a cloud platform,
for enterprise email access.
SD-WAN can easily interact with applications
like AWS, Dropbox, Azure, Office 365 and many, many more.
So this means that hosting applications
in either public or private clouds,
will allow direct traffic between the cloud application
and the branch location.
It will allow that rather than backhauling
all of the traffic through a central data center.
So that's a big reason that we're moving more and more
toward SD-WAN.
SD-Wan solutions can intelligently control
the path of traffic,
in order to optimize traffic flow,
and to reduce unnecessary bandwidth in our networks.
Now you might be wondering, what happens to the
security inspection services,
since that traffic is now not being routed
through the data center any longer.
That's been addressed as well,
because most SD-WAN offerings
now provide end-to-end traffic encryption and inspection.
Additionally, more and more
next generation features are being added.
Things such as anti-malware systems,
and bot-net intervention.
Many features that you would see
on next generation security devices.
Another big advantage of SD-WAN solutions,
is that they provide traffic transport independence.
And in order to understand that,
we need to understand the difference
in an overlay network, and an underlay network.
An underlay network is simply the
physical network infrastructure,
responsible for the delivery of packets.
We see that here in this example.
We have several sites and a data center,
all interconnected by physical infrastructure.
SD-WAN on the other hand,
that is a type of overlay network.
And overlay networks are simply a virtual network
built on top of an underlay network,
or built on top of the actual physical infrastructure.
Overlay networks aren't anything new,
those have been around for a long, long time.
Overlay networks even include things like
voiceover IP, or VPNs.
Those run on top of the internet as an overlay.
With SD-WAN as the overlay network,
this gives us transport independence.
And by this we mean that our WAN connections,
can be made up of all different types
of connection combinations.
We might have some LTE connections,
we might have serial connections,
wireless connections, satellite connections, MPLS,
it doesn't matter what's running as our underlay network
because SD-WAN solutions can very intelligently
and coherently choose the best data path transmission.
And that's great news for us as network administrators,
because it simplifies our job even further.
Now that we understand what SD-WAN is,
and why that's being increasingly used
in our modern enterprise networks,
in our next video we want to take a look
specifically at Cisco's SD-WAN solution,
and how we would see that commonly implemented
in an enterprise network.