So for the matching exercise right above this video,
I wanted to take just a minute right now
and review our answers together.
So regarding these components, an overlay segment.
An overlay segment really is a layer two
logical broadcast domain.
And think of a broadcast domain like a VLAN
where if a broadcast is sent at layer two
into that network segment it's gonna be forwarded
or propagated to all other devices
that are in that same logical broadcast domain.
So just like a VLAN is a broadcast domain
or a subsection if you will, WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
or a subsection if you will,
of a physical switch like a separate room
instead of a building.
At layer two when we implement overlay segments
instead of NSX,
each of those overlay segments
is also a logical layer two broadcast domain.
And here's an example if this VM here,
we'll call that VMA is being hosted on ESXi-A
and it's connected to this logical segment
called Segment 10.
And then over here on ESXi-B
for another VM over here is also connected
to that same logical segment.
VMA over here and VMB over here
are both in the same layer two broadcast domain. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
are both in the same layer two broadcast domain.
And the same would be true for these two VMs here.
If this was VMC, for example, and VMD
and VMC is being hosted on ESXi-A over here,
but connected to this logical segment called Segment 20.
And over here VMD is being hosted by ESXi-B
and is connected to this logical segment.
Then VMC and VMD are both in the same
layer two logical broadcast domain.
So if this VM here VMC sent a broadcast in the network,
that broadcast should be seen over by VMD over here, WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
that broadcast should be seen over by VMD over here,
over on ESXi-B.
Now behind the scenes to make that all happen,
ESXi-A would be forwarding that over the tunnel
using GENEVE for encapsulation
and send that information over the tunnel
where ESXi-B would deencapsulate it
and then forward it to the destination.
Or in the case of layer two broadcast that destinations
where that layer two broadcast need to be sent.
So this topology, everybody in segment 20
sees all the broadcasts for segment 20
and everybody in segment 10 sees the broadcast
associated with VLAN 10.
Now there are some shortcuts as well that can be taken
by the ESXi host. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
by the ESXi host.
For example, if there's an ARP request that VMA is making
and ESXi-A knows exactly where that layer two address lives,
it can go ahead and respond back to VMA
and answer that ARP response
without actually sending that traffic over the tunnel.
But that's due to the control plane here of the NSX manager
and it populating the ESXi transport nodes
regarding where those MAC addresses live.
But at the end of the day, an overlay segment
is like a layer two broadcast domain.
And that concept of the common layer two broadcast domain
also leads us to this third option, WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
also leads us to this third option,
which is part of our matching,
which is VMs that should be on the same segment
are VMs that are connected
to the same layer two broadcast domain.
So any VMs for example, VMA here
and VMB here, if they're both connected
to the overlay segment 10,
they're both in the same layer two broadcast domain.
And as a result, they should also at layer three
have a IP address on the same subnet.
So if we have a 10.10.10 network with a slash 24.
Over here this one could be
for example 10.10.10.50. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
for example 10.10.10.50.
And over here this could be 10.10.10.51
both in the same layer three subnet of 10 10 zero.
So I'm just gonna draw a little arrow here
just to reinforce that Vms
who are in the same layer two broadcast domain
at layer two should also have an IP address
in the same subnet at layer three.
So lemme clean that up a little bit.
And one of the matching options in the question above
was about the IP address that's used
to reach the other end of a GENEVE tunnel.
And that IP address associated with the GENEVE tunnel
is the tunnel endpoint address. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
is the tunnel endpoint address.
So here in this topology, this tunnel endpoint address,
here on ESXi-A is at 11.111.11.11.
And over here in ESXi-B it's 22.22.22.22.
And if we were to look at the VM kernel adapters
on each of these hosts, we would find a VM kernel adapter
with that associated IP address.
So this host is using the VM kernel adapter
and it's corresponding IP address for the tunnel endpoint
for the logical communication over the transport network
as they send data back and forth,
for example, from ESXi-A encapsulating the data
and sending it over to ESXi-B. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
and sending it over to ESXi-B.
And then there was a couple matches about this option here
of get segments and this option here
about get logical switches.
And just to confirm that in the world of NSX,
let's head over to the command lane interface
over here on ESXi-A.
So here on ESXi-A, I've got an SSH session open
to go into the NSX cli,
we'll type in nsxcli, press enter.
And boom, now we're at the nsxcli
on this host transport node.
So here, if we do the command get segments
and press center, it's currently showing me
that on this ESXi host, WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
that on this ESXi host,
it has no logical segments associated with it.
(laughs lightly)
And I'm a little shocked. I'm like, whoa, why is that?
And the reason here that it's showing those segments
is because at the moment
I'm doing this demonstration of this review,
there are no VMs that are running
that are attached to any of our segments.
So I also recommend, let's just go ahead
and power up a couple VMs and then come back
and take a look here on ESXi-A
and see whether or not it now knows about a segment.
So here on the vSphere client,
let's click on the network tab right here. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
let's click on the network tab right here.
Let's go down to segment 10
and let's identify a VM that's both connected to segment 10
and also it's running on ESXi-A
or will be once we powered on.
So at the moment, this VM right here
is not currently powered on.
So we'll select it, we'll go ahead and we'll right click
and we'll click on power and then power it on.
And so now that this VM is now gonna be powered up
and is connected to this segment, segment 10 yellow,
if we go back now to the nsxcli on ESXi-A.
ESXi-A is now gonna be aware
of that layer two broadcast domain, WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
of that layer two broadcast domain,
this segment called Seg 10 yellow.
So let's go back to the cli and verify that.
So back at the cli, my hands will never leave my arms.
We'll simply hit the up arrow key.
For get segments, press enter and baa bing baa boom.
It now knows about this VNI
is virtual network identifier for this segment.
Here's the UUID for that segment
and there's its name Seg 10 yellow.
Now synonymous with this command of get segments,
we could use the older command of get logical switches.
Just like that to show us the logical switches.
And that's also gonna show us the same logical switch. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
And that's also gonna show us the same logical switch.
So here we have the same VNI number, we have the same UUID,
and we also have the same name.
So even though the commands are being migrated
from the logical dash switches over to the command segments,
we still have a lot of backwards compatibility
with the older set.
And as of this recording,
I'm in the version 4.1 X flavor of NSX.
So for our matching game,
the command get segments
is synonymous with get logical switches
and the command get logical switches
is synonymous with get segments.
So those two can be used interchangeably. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
So those two can be used interchangeably.
So thanks for joining me in this skill
regarding deploying some NSX overlay segments
and also verifying them.
And I'll see you my friend, in the very next skill.
Until then, I hope this has been informative
and I'd like to thank you for viewing.