Well, big takeaway from this skill should be that we understand how traffic
flows among
the different virtual machines that exist inside of a single virtual host or a
hypervisor,
and then also between different hypervisor, different vswitches, and talking to
devices
out on the rest of the network, including a default gateway.
So let's go ahead and go through these challenges.
And we need to keep in mind, first and foremost, that there is going to be pin
ning involved
here.
And so we might just want to take a moment to decide where these VMs are going WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
And so we might just want to take a moment to decide where these VMs are going
to be
pinned.
Now we weren't told this, but they are going to get pinned to one of these
links.
Now they could both get pinned to the same link.
That is certainly an option as well.
So maybe we just do that here in this situation, and then VMC it could be to
either one of these
uplinks.
So now that we've established the pinning, let's go through these challenges.
So first of all, VMA sends a packet to VMB.
So once again, we're talking about downstream switching. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
So once again, we're talking about downstream switching.
This is going to act like any other switch.
It's going to directly switch and allow VMA and VMB to communicate with each
other without
ever sending packets off of the box.
Now interestingly, this can be a challenge because we might have network
monitoring up
here, and we want to know what that traffic looks like.
And so this can make it so we have a hard time seeing that traffic.
But it is a reality.
Now we could possibly set up span on the virtual switch and send information
about that traffic
off of the box. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
off of the box.
But by default, the native switching of this V switch is going to make it so
that this
switch up here never sees those packets.
And so if we have security policy up here as well, that's going to get
completely bypassed
by the fact that again, our physical network never sees the packet, which is
interesting,
especially if the network team is in charge of the physical network, but the
server team
is in charge of this network.
Well, that as you can imagine might cause a little bit of conflict there.
Now moving on to the next one, virtual machine, a sent a packet to virtual WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
Now moving on to the next one, virtual machine, a sent a packet to virtual
machine C. Well,
I can't bridge this gap.
There is a air gap between the two virtual switches.
I guess if we want to use air quotes for air gap, there we might want to do
that.
It's all in software after all, but we do see that there's traffic isolation
here.
So for a VM a to communicate to VMC, we're going to need to go off of its
pinned link
here or through its pinned link up to the switch.
The switch will get will take that packet, check its cam table and see that the WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
The switch will get will take that packet, check its cam table and see that the
MAC address
lives out this port, it's pinned link, and that will eventually get to virtual
machine
C.
So this traffic isolation are these is going to be achieved by deploying
multiple V switches,
but we also get the traffic to show up on the physical switching infrastructure
.
So that's another way that we could do that in order to see the traffic on our
network.
Now next virtual machine, a sent a packet to its gateway.
Let me change colors here. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
Let me change colors here.
We're trying to send to our gateway.
Well, once again, we are going to go out our pinned link.
We don't have any other choice here.
That's the definition of pinning.
So I'm going to send it up to the switch and that'll get switched over to the
appropriate
port and sent out to the gateway.
And by the way, VMB would do the same thing.
It would send out the same pinned link as we see and it would get sent to the
gateway
this direction.
So we've got multiple virtual machines that can all access their default gate
ways.
Now lastly, virtual machine A sends a broadcast packet. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
Now lastly, virtual machine A sends a broadcast packet.
Our diagram is getting a little bit busy here, but if I send a broadcast packet
now into
the virtual switch, what happens?
Well, a virtual switch is going to do what any other switch would do.
It's going to send a copy of that packet to all of the other virtual machines
that
might be attached to that V switch.
But notice that VMC here doesn't receive it from the V switch.
It's not attached to that V switch.
So does it get a copy of it?
Well, yes, because like all these other packets, we're going to send a copy up WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
Well, yes, because like all these other packets, we're going to send a copy up
to our pinned
up link.
And so the switch is going to send that flooded traffic out all of the other
links.
Now is it a problem that it got sent back down to the same virtual switch?
Well, no, because it's going to show up on a pinned link that all these other
virtual
machines have already received a copy of that.
And so we're going to prevent that from happening.
And then same thing over here, we're going to prevent this from going anywhere, WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
And then same thing over here, we're going to prevent this from going anywhere,
but this
one since it hits the pinned up link is going to follow the pinned up link and
make sure
our copy does get to virtual machine C. So what we see here is that our pinned
traffic
is a great way to achieve load balancing and redundancy, but it doesn't cause
looping.
And we don't have to run spanning tree, which is the most beautiful thing at
all.
Of all, now it does have to exist at the very edge of our networks.
We can't run pinning in the middle of our networks, but because we have so many
of these
hypervisors and virtual hosts in our data center, as well as, like I said, WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
hypervisors and virtual hosts in our data center, as well as, like I said,
technology like
UCS.
We do see that pinning is important inside of data center networking.
I hope this has been informative for you and I'd like to thank you for viewing.