Alright, we are now up and running over on the left there at sites 11 and 12,
but we
now want to zoom in on site 13 and give it a look.
Because notice how we have this site laid out.
We have two edge devices.
And that's going to be the case for a lot of our more critical locations,
because we
need to start thinking about redundancy and the fact that maybe I should have
two routers
there or two edge devices, because I don't want my whole site to be lost if I
have a
single edge failure.
In fact, we're going to be diving into T-lock extensions in the next skill, and
that takes
it even to the next level, because we want to make sure that, for example, edge
14 here
would be able to still leverage the internet through edge 13, and edge 13
should be able
to access MPLS via edge 14.
That would take care of the possibility of, let's say, edge 13 losing its
internet connection,
well, we might still have traffic forwarded to edge 13, so we want to be able
to leverage
the MPLS circuit and ultimately maintain our SD WAN topology regardless of what
happens
with the underlay.
And that's what we have to be really thinking about here.
We're forming an overlay network.
We're using tunnels, the Swiss Army line and knife of networking, to be able to
create
whatever type of overlay I want, and if that means that I'm forming connections
across
MPLS via a slightly different type of underlay, as far as the overlay is
concerned, the topology
has maintained itself and it stayed up.
Even if, from my perspective, I'm looking at it and saying, "Okay, yeah, but
there
were physical failures and yeah, we might have lost a couple of tunnels, but we
are at least
still able to use an MPLS tunnel going across a different set of physical
connections."
So that will be coming up again in the next skill.
In this skill, what we want to do is we want to build out this network here.
We want to worry about the fact that we've got two of these edge devices and we
want
to be able to deploy hosts here and make sure that we can use one of them and
if it fails,
that we can use the other one to get out to the rest of the network.
So those are going to feel a little bit like an enterprise networking design
class because
we need to think about things from a redundancy perspective, including the
first hop redundancy
protocol of choice.
And when I say choice, it's a very loose term because we don't have a choice,
we have
one option for an FHRP at the time of this video and that would be the industry
standardized
VRRP.
VRRP, which stands for the virtual router redundancy protocol, is what the
industry created when
Cisco created HSRP.
Now a lot of us who manage Cisco networks are very familiar with HSRP and
likely deploy
them in our network.
However, because HSRP requires Cisco hardware, well, when Viptela first created
this solution,
they didn't have a choice, they had to go with VRRP.
Now we can look at it and say, "Okay, that's great."
That originally we had VRRP in the same way that Viptela didn't support EIGRP.
So now that we have Cisco Edge devices, we can support EIGRP.
Cisco did add support for that.
So we might expect that we could also deploy HSRP.
Well, that's not the case.
With, for better or worse, at the time of this video, Cisco hasn't added HSRP
support,
which means that we're stuck using VRRP.
So truly just when it comes to the decision point, it's not a very difficult
decision,
we're simply going to take the protocol that we're allowed to use.
So what we're going to do here is we're going to build out a network.
And the way we're going to build this out logically is by having a network that
allows
us to connect another Ubuntu host here.
And so we want to create a subnet.
In our case, it's going to be 10.10.13.0/24.
And we are going to keep this exclusively in VPN 10.
Yeah, we could deploy another subnet here and add VPN 20 into the mix.
But for the sake of really focusing in on the dual edge design, as well as T-
lock extensions,
which as we mentioned, we'll be coming up here shortly.
I just want to focus in on a single VPN for the sake of keeping things simple
otherwise.
There's a lot to digest here.
And so we're just going to extend a single VPN down, which will remove or
otherwise reduce
the amount of physical connections we have to end up making here.
So how are we going to do this?
Well, we're going to deploy another one of these unmanaged switches here.
So an unmanaged switch, which will allow us to connect our Ubuntu machine to
edges 13
and 14 without having to worry about creating a whole bunch of the land
configuration on
a managed Cisco switch.
So the Ubuntu host will be using the .50 address.
And so it will be 10.10.13.50.
And then interestingly, edges 13 and 14 here.
What are we going to use upstream?
Because before we just said, well, this will use that 13 because it's edge 13.
This will use that 14 because it's edge 14.
But now what do we use for the default gateway here?
Dot 13 or dot 14?
Well, VRP is a little bit interesting VRP allows us to create a virtual IP that
will
be used as the default gateway, just like with HSRP same concept.
However, VRP allows us to then use one of these existing IP addresses.
So edge 13 will be dot 13.
And it will also be the virtual IP address that's used by edge 14 if edge 13
were to
go down.
So the default gateway will point to dot 13.
And then when we look at this from a topology perspective, what ends up
happening here is
the Ubuntu machine will use edge 13 as its default gateway to try to get out to
the
rest of the world.
However, if for any reason edge 13 were to have a problem and it goes down,
well, edge
14 will start to respond to our end or our requests for dot 13.
And it will allow us to send traffic this way.
So VRP does work a little bit different than HSRP in that regard.
However, in the end, it's accomplishing the same thing, which is providing us
with default
gateway redundancy.
Naturally, if edge 13 comes back online, because it owns dot 13 on its
interface, it's going
to have to take back over as the VRRP master.
And so we don't have to worry about preemption or anything like that.
We just have a master and a backup in the VRP terminology.
So the master and the backup will operate in this way because again, we're
going to use
edge 13's IP address as the virtual IP address for our default gateway.
Now one other thing in all of this for us to notice, and that has to do with
the fact
that edge 13 has a connection to the internet here, edge 14 has a connection to
the MPLS
network.
And this connection here, gig two going out to the internet, this is only for
control
components.
So we are not leveraging that connection for edge 14.
So the topology that we're building here shows that edge 13 has a single WAN
connection.
Edge 14 has a single WAN connection.
So that's the type of site we're building.
And it's one that we can expect to see in the real world as well.
When we have maybe an important site, we want to have redundancy.
Well we might end up splitting a connection like this so that we have one
connection going
to one router, one connection going to the other router, and now it's our job
to build
the redundancy onto the LAN side in order for us to make use of the fact that
we have
redundant routers.
So that'll be our focus for this skill is to bring this site online.
Let's go ahead and dive into more details about how we're going to get that
done.