1
00:00:00,390 --> 00:00:10,560
So another problem for Paul is he wants these VMS VM one and VM two to be in the same subnet.

2
00:00:10,980 --> 00:00:13,620
But Peter, the network guy won't allow that.

3
00:00:13,950 --> 00:00:21,030
He wants to implement a rooted infrastructure, so to contain broadcasts and for better network design.

4
00:00:21,510 --> 00:00:30,180
Peter, the network engineer, wants the VMs to be in separate VLANs and tells Paul that a VLAN cannot

5
00:00:30,180 --> 00:00:32,430
span across the data center.

6
00:00:32,670 --> 00:00:37,740
So VM one and VM two need to be in separate subnets.

7
00:00:38,250 --> 00:00:39,960
Now, this is a problem for Paul.

8
00:00:40,200 --> 00:00:50,010
He wants to have VMs on multiple hypervisors in the same subnet, so he wants a VM running on ESXi server

9
00:00:50,010 --> 00:00:58,590
on the left as well as iSCSI server on the right as well as on say a KVM server or other ESXi servers.

10
00:00:58,680 --> 00:01:01,950
All those virtual machines need to be in the same subnet.

11
00:01:02,190 --> 00:01:05,970
So he wants to span subnets across the data center.

12
00:01:06,420 --> 00:01:08,910
Peter, however, says that's not possible.

13
00:01:10,550 --> 00:01:16,760
Another advantage for the overlay setup is the virtual machines can be in the same subnet.

14
00:01:17,270 --> 00:01:25,040
So VM one and VM two can be in the same subnet, even though they span across a routed infrastructure.

15
00:01:25,640 --> 00:01:32,660
So there's nothing stopping virtual machine one, virtual machine two, virtual machine three and virtual

16
00:01:32,660 --> 00:01:35,870
machine four all being in the same subnet.

17
00:01:35,870 --> 00:01:42,230
Even though they span different parts of the data center, the tunnels between the hypervisors can be

18
00:01:42,230 --> 00:01:46,820
dynamically set up and torn down depending on where the VMs are.

19
00:01:47,180 --> 00:01:54,920
So if a virtual machine is moved via the motion to a different ESXi server, the VXLAN tunnel can automatically

20
00:01:54,920 --> 00:01:59,510
be torn down and re-established to the new hypervisor.

21
00:01:59,990 --> 00:02:08,539
Basically, with a virtual network or an overlay network, the server administrator can create and tear

22
00:02:08,539 --> 00:02:14,540
down virtual networks without involving the network administrator.

23
00:02:15,020 --> 00:02:21,020
The physical infrastructure simply needs to move traffic from one part of the network to another part

24
00:02:21,020 --> 00:02:21,920
of the network.

25
00:02:22,460 --> 00:02:27,620
Now, obviously, you need to think about quality of service and other factors, but the moral of the

26
00:02:27,620 --> 00:02:34,250
story is the network administrator's role and responsibilities has been reduced dramatically.

27
00:02:34,760 --> 00:02:42,530
By using an orchestration tool, the server administrator can dynamically, efficiently and very quickly

28
00:02:42,770 --> 00:02:46,070
at scale deploy virtual networks.

29
00:02:46,490 --> 00:02:48,980
And I'm going to show you an example of that in a moment.