Well, this is a software defined access fabric, meaning that it's encompassing
our access layer.
Well, our access layer is more than just wired clients.
We happen to have a lot of wireless devices out there these days, and because
all of our
access points reside at the access layer, it's going to have to be a part of
our architecture.
Now what we're going to find is that we have two different ways of building
wireless.
We can integrate it into the fabric, which is what we're going to talk about in
this
video, and then we can also say, you know what, we just want to deploy a WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
video, and then we can also say, you know what, we just want to deploy a
wireless solution
independent of the fabric itself.
And basically just treat the fabric like it's a network path at that point,
just a mechanism
for communicating between access point and wireless LAN controller.
And so we'll talk about that in the next video.
So now let's just focus on how can we integrate our access points and wireless
LAN controllers
into an SDA fabric?
Well as we can imagine, just like with a traditional wireless architecture, our WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
Well as we can imagine, just like with a traditional wireless architecture, our
access points are
going to connect into our access layer switches, and they'll receive power over
ethernet.
From these connections, remember these fabric edge nodes are just catalyst nine
case switches
for the most part.
We might have some more legacy 3650 3850s in there as well, but especially in
the modern
network, lots and lots of catalyst nine case.
So it's the same switches we'd be deploying into our access layer, even if we WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
So it's the same switches we'd be deploying into our access layer, even if we
weren't
deploying SDA.
So again, access points connecting, getting power over ethernet, all of these
things.
Well if we're going to integrate it into the fabric, these become known as
fabric access
points.
This is largely a terminology concept, but again, we do have the option of
building
wireless independent of the fabric.
And so it is an important distinction that if we see a conversation around a
fabric access
point, if we see it listed in the wireless LAN controller as being fabric WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
point, if we see it listed in the wireless LAN controller as being fabric
enabled, then
that's an access point that is fully integrated with the fabric.
So we're using the fabric word in the same way that we have fabric edge nodes
and fabric
border nodes.
This word fabric is being used very intentionally here.
Now let's think through things from an access point architecture perspective.
We know that we need a wireless LAN controller somewhere in the network. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
We know that we need a wireless LAN controller somewhere in the network.
And that is for the sake of performing lightweight access point operations.
And we need to build capwap tunnels to the wireless LAN controller.
So how do we get to that point?
Well, the access point is going to connect and it's going to receive an IP
address via
DHCP.
This is a benefit to lightweight access points.
We don't need to worry about what IP address they have.
We don't need to worry about static IP addresses in most situations.
So we leverage DHCP. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
So we leverage DHCP.
Well now this access point is simply an endpoint identifier to the upstream
fabric edge node.
And so it's actually going to do the registration.
So we've got our control plane node up here.
And we register just like we talked about.
We register the access point and both of these are going to do that
registration for the access
point as if it's any other device connecting to the switch, a laptop or a PC or WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
point as if it's any other device connecting to the switch, a laptop or a PC or
anything
along those lines.
Meanwhile the access point is going to learn about the wireless LAN controller
the traditional
way that we learn about the wireless LAN controllers.
And usually that involves DHCP option 43 where the DHCP itself delivers the
wireless LAN controller
IP address to the access point.
Either way the access point now knows where the wireless LAN controller is and
therefore
it can now build a tunnel towards the wireless LAN controller.
It can send traffic to this connection. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
It can send traffic to this connection.
But here's the question, where is the wireless LAN controller and how do we
attach it to the
fabric?
Well, we are going to attach it through none other than a fabric edge node.
So here we have a third fabric edge node.
It's another Nexus or catalyst 9k.
And so we are connecting in and now we can refer to this as a fabric wireless
LAN controller.
So in the same way that if an access point is integrated with the fabric, we're WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
So in the same way that if an access point is integrated with the fabric, we're
going
to do the same thing with the wireless LAN controller here.
And so it will also get registered by the way to the control plane node.
So all of these devices at this point are simply endpoint identifiers mapped to
the
R-locks of the individual fabric edge nodes.
And so these are simply endpoints that can communicate with one another.
At this point it's going to get a little more integrated but when everything is
first coming
online they're all just devices that need to communicate with one another. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
online they're all just devices that need to communicate with one another.
And so at this point we can form a cab web tunnel.
And so we're going to use the actual overlay type of communication.
So again if there's a laptop here that's connected to the same switch, I'm also
communicating
through VX LAN tunnels to get across to another fabric edge node or maybe down
here.
And so we can think of it the same way.
I'm simply extending communications through this fabric edge node destined for
this wireless WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
this wireless
LAN controller.
So I've got to find out where the wireless LAN controller is as an edge node.
I send my map request, it gets forwarded down to the appropriate edge node, I
get a map
reply back and now I know where to send it.
Ultimately I'm sending this traffic in the VX LAN tunnel that communicates with
that fabric
edge node that will connect me to the wireless LAN controller and we build a
cap-wap tunnel
this way.
Now notice what I just said. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
Now notice what I just said.
We are encapsulating this traffic inside of VX LAN tunnel and the traffic we're
encapsulating
is a cap-wap tunnel.
These are two different tunneling mechanisms operating at the same time.
Yes, my cap-wap is inside of a VX LAN tunnel which has MTU implications.
We need to increase the MTU already by 50 bytes for the VX LAN like we said and
now
if we're performing wireless across this we're going to need to increase it WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
if we're performing wireless across this we're going to need to increase it
again because
of the double encapsulation.
Now here is just cap-wap going from the access point to the 9K.
The 9K then has cap-wap inside of VX LAN going to the other 9K and then we just
deliver
pure cap-wap communications down to the wireless LAN controller.
So the two end devices, the wireless LAN controller and the AP, they don't see
the VX LAN, they
are just seeing the cap-wap traffic that was carried across the fabric. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
are just seeing the cap-wap traffic that was carried across the fabric.
At this point everything is fairly normal.
We're just using SDA as a transport mechanism.
But now here is where we can activate the fabric portions of this architecture.
The wireless LAN controller is going to see this access point come online.
It's going to register this access point and it is going to be configured with
catalyst
center integration.
So we let it know about catalyst center and therefore it becomes aware of the WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
So we let it know about catalyst center and therefore it becomes aware of the
control
plane node.
So first of all the access point is going to register to the wireless LAN
controller.
The wireless LAN controller is then going to send a query about this access
point to
the control plane node.
The purpose of this is to find out is the AP fabric attached or not.
Because if it is fabric attached then we want to let the fabric become aware WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
Because if it is fabric attached then we want to let the fabric become aware
that there's
this end point out here that happens to be an AP.
If the control plane node has a registration for that particular IP address
then we're
going to know that okay this access point is part of the SDA fabric and it didn
't come
through a border node or some indirect path or anything like that.
If we get a response back from the control plane node saying that yes this is
indeed
fabric attached then I'm going to register as the wireless LAN controller. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
fabric attached then I'm going to register as the wireless LAN controller.
I'm going to register to the control plane node to say that I want to register
the MAC
address for the AP.
Keep in mind the AP was registered from an IP perspective because we deal with
IP addresses
when we're talking about registering devices to the control plane node.
So we registered the IP address but now I want to register the MAC address.
I'm essentially claiming ownership of the access point and I'm alerting the WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
I'm essentially claiming ownership of the access point and I'm alerting the
control
plane node to say that IP address specifically that endpoint identifier is an
access point.
So now the control plane node is aware that that particular EID that was
registered is
actually an access point and it should be treated a little bit different.
So here's the fascinating fourth part about all of this. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
So here's the fascinating fourth part about all of this.
If we say for over here the control plane node is actually going to alert the
fabric
edge node about the fact that the endpoint identifier is an access point and
then the
fabric edge node is going to form a VXLAN tunnel to the access point.
We're actually forming a VXLAN tunnel to the AP.
This is pretty interesting because we know that we've got VXLAN inside of the WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
This is pretty interesting because we know that we've got VXLAN inside of the
fabric
and all of the tunnels connecting all of the different edge nodes but now on
top of saying
that we're running capwap inside of all of this I'm now actually going to run
not just
capwap but I'm also going to extend a VXLAN tunnel to the access point.
Meaning that the access point sends some traffic outside of the tunnel
specifically the capwap
communication still goes outside of the VXLAN tunnel but my wireless devices my WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
communication still goes outside of the VXLAN tunnel but my wireless devices my
wireless
stations, these wireless stations as traffic comes to the access point it is
going to be
sent out the VXLAN tunnel to the fabric.
Now that is a major distinction because if we think about lightweight access
points usually
we're sending wireless station traffic into the capwap tunnel which means we
have to go
all the way down to the wireless LAN controller.
We don't have to do that with SDA.
Our station traffic basically our data plane does not use capwap in this top WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
Our station traffic basically our data plane does not use capwap in this top
ology, in this
architecture.
When we're talking about fabric attached access points we are going to build VX
LAN tunnels
to our upstream devices and we're going to send our wireless station traffic
through
those VXLAN tunnels directly to the fabric edge node.
Meaning that when a wireless station packet shows up, so here's our wireless WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
Meaning that when a wireless station packet shows up, so here's our wireless
frame it
just showed up here.
I'm going to treat it as if it was a wired frame.
I'm going to check my cache, I'm going to figure out which fabric edge node to
send
it to and I'm going to encapsulate it into VXLAN and send it directly to my
next switch.
So I'm not actually sending it to the wireless LAN controller anymore.
Now am I still running capwap and mention that I'm still sending some amount of
traffic
via capwap and the answer is yes. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
via capwap and the answer is yes.
Control plane traffic still gets sent via capwap to the wireless LAN controller
.
This is how we can do radio resource management such as channel allocation.
We can do a lot of registering of information such as registering of wireless
stations which
helps with roaming.
That's all very important and continues to ride via the capwap tunnels for
wireless control
plane.
But the data plane traffic itself not going to be sent to the wireless LAN
controller via
capwap.
Now one last point I'd like to note is the fact that our wireless stations, WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
Now one last point I'd like to note is the fact that our wireless stations,
they do still
get registered via that control plane to the wireless LAN controllers and again
this is
important for the sake of roaming.
So if a wireless station roams from one access point connected to one fabric
edge node and
now all of a sudden I'm on another access point which is on a different fabric
edge
node we need to update the fabric to the fact that that wireless station has ro
amed.
Well when we roamed to the new AP it's going to perform that station WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
Well when we roamed to the new AP it's going to perform that station
registration message
to the wireless LAN controller to alert it to the fact that it has this new
station and
the wireless LAN control is going to say wait a second that was already on a
different
access point this is now roamed we need to update everyone about the new
location.
As such it sends an update to the control plane node.
So that the control plane node can update its EID to our lock mapping and it WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
So that the control plane node can update its EID to our lock mapping and it
can make
sure that it's sending traffic to the appropriate fabric edge node to
ultimately land on the
correct access point to get sent down to where the wireless station now resides
.
[BLANK_AUDIO]