1
00:00:13,570 --> 00:00:21,610
So that was the configuration for VLAN 10, that means that for the PC and VLAN 10 we can configure

2
00:00:22,210 --> 00:00:33,250
the PC to use a default gateway of that HSRP router, the IP address that we need to configure the PC,

3
00:00:33,250 --> 00:00:37,930
as is shown in the output here, 10.1.10.10, 

4
00:00:38,970 --> 00:00:44,280
so 10.1.10.10/24 subnet mask.

5
00:00:45,590 --> 00:00:47,450
So I'll open up a command prompt.

6
00:00:49,980 --> 00:00:57,870
IP config, that's the IP address of the PC, can it ping its default gateway?

7
00:00:57,900 --> 00:00:58,830
Yes, it can.

8
00:00:59,550 --> 00:01:08,700
Now notice the arp cache, notice the Mac address used here for the default gateway is the HSRP router.

9
00:01:09,980 --> 00:01:15,530
In other words, the virtual Mac address, as we can see over here.

10
00:01:16,960 --> 00:01:24,610
So once we've got our network configured, we should be able to ping devices in other VLANs. So let's

11
00:01:24,610 --> 00:01:32,470
complete the configuration of HSRP and both of these core routers and then configure default gateways

12
00:01:32,590 --> 00:01:36,100
on other devices and test connectivity.

13
00:01:37,400 --> 00:01:49,980
So configuration on VLAN 10 is as follows, on VLAN 20 this device is not the spanning-tree root.

14
00:01:50,980 --> 00:01:54,940
So we want core 2 to be

15
00:01:55,830 --> 00:02:02,130
the HSRP active router for VLAN 20, because it's the root.

16
00:02:05,240 --> 00:02:14,510
So all we'll do here is use the command standby IP 10.1.20.254 now before I configure switch

17
00:02:14,510 --> 00:02:19,120
2 I want this device to become the active router.

18
00:02:19,820 --> 00:02:21,260
So we need to give it some time

19
00:02:21,590 --> 00:02:28,400
and then I'll show you what happens when the other device comes online with a higher priority and preemption.

20
00:02:29,550 --> 00:02:38,100
Switch 2 will become the active router once we configure it, but notice now that core 1 is active.

21
00:02:38,700 --> 00:02:40,170
So if I type show standby

22
00:02:42,990 --> 00:02:51,090
for VLAN 20, the local router is the active router because the standby router is not known.

23
00:02:52,240 --> 00:02:59,080
Virtual IP address is this notice the virtual Mac address is the same Mac address, but that's not a

24
00:02:59,080 --> 00:03:06,370
problem because these devices are in different VLANs, so they don't see each others traffic.

25
00:03:07,150 --> 00:03:13,840
So devices in one VLAN won't be confused with sending traffic to the wrong device in another VLAN

26
00:03:14,290 --> 00:03:17,170
because VLANs separate Mac addresses.

27
00:03:20,650 --> 00:03:26,890
So on the switch interface VLAN 20, standby one IP address.

28
00:03:28,080 --> 00:03:37,770
is gonna be 10.1.20.254, but now what I'm gonna do is I'm going to force this device to

29
00:03:37,770 --> 00:03:46,470
have a higher priority and I'm gonna force preemption so that it becomes the active router. Notice

30
00:03:46,470 --> 00:03:48,960
as soon as I did that, it became active.

31
00:03:50,900 --> 00:03:54,300
I'll show you in a moment what happens if we don't use preemption.

32
00:03:55,230 --> 00:04:02,910
So show standby shows us that the local switch is the active router, virtual IP address is

33
00:04:02,910 --> 00:04:05,700
this, local router is active.

34
00:04:06,120 --> 00:04:09,480
Standby router is unknown but let's check again.

35
00:04:10,200 --> 00:04:10,860
There you go.

36
00:04:11,190 --> 00:04:11,670
Standby

37
00:04:11,670 --> 00:04:13,110
router is core 1

38
00:04:13,710 --> 00:04:18,029
and what you'll notice on core 1 is that the state changed to standby.

39
00:04:20,130 --> 00:04:31,470
So show stand by again for VLAN20 shows us that this router is no longer the active router it is the

40
00:04:31,470 --> 00:04:38,250
stand by router. Router 2 or Core 2 has become the active router

41
00:04:39,510 --> 00:04:42,330
and we can see something similar on this side.

42
00:04:43,030 --> 00:04:52,040
OK, so that's VLAN 20, show spanning-tree VLAN 30 core 1 is the root for VLAN 30.

43
00:04:52,560 --> 00:04:56,100
So we want core 1 to become the HSRP active.

44
00:04:58,410 --> 00:05:07,740
But let me show you what happens, firstly, if you don't configure preemption, so I'll specify on core 2 that

45
00:05:07,740 --> 00:05:13,550
for VLAN 30 the standby router is 10.1.30.254

46
00:05:14,100 --> 00:05:17,700
that's all I'll configure. Once again

47
00:05:20,500 --> 00:05:28,480
for VLAN 10 and VLAN 30 we don't want the router to be the active router so all I've configured

48
00:05:28,780 --> 00:05:31,510
is this command standby one, an IP address.

49
00:05:34,250 --> 00:05:47,570
Now on core 1 interface VLAN 30 standby 1 IP 10.1.30.254 standby 1 priority

50
00:05:48,560 --> 00:05:49,240
200.

51
00:05:49,820 --> 00:05:54,220
So I'm going to change the priority but not configure preemption.

52
00:05:54,890 --> 00:05:56,200
So notice the difference.

53
00:05:56,420 --> 00:06:00,410
Show run shows us the output on VLAN 10

54
00:06:00,410 --> 00:06:05,960
it's configured with preemption, on VLAN 30 it's not configured with preemption

55
00:06:06,440 --> 00:06:09,380
and notice it became a standby device.

56
00:06:09,980 --> 00:06:12,400
This device is already the active device.

57
00:06:13,160 --> 00:06:23,270
So without preemption, if a device is already the active device or active router the other device

58
00:06:23,270 --> 00:06:26,670
it is not gonna force itself to become the active router.

59
00:06:27,350 --> 00:06:28,730
So show standby again.

60
00:06:29,480 --> 00:06:31,670
Local router is the active router.

61
00:06:32,210 --> 00:06:34,460
Just need to give it some time to sort itself out.

62
00:06:35,840 --> 00:06:37,520
On this side it's going to stand by.

63
00:06:41,520 --> 00:06:49,470
So core 1 has learnt that core 2 is the active router and the local device is the standby router.

64
00:06:50,850 --> 00:06:56,610
On this site that should hopefully sort itself out, that might be a packet tracer issue, but notice

65
00:06:56,610 --> 00:06:58,790
the local router is the active router.

66
00:06:59,520 --> 00:07:02,580
We still see standby router as unknown.

67
00:07:03,360 --> 00:07:09,360
The point is, is that this device, even though it's got a higher priority, has not become active.

68
00:07:10,590 --> 00:07:12,020
And that's not what we want.

69
00:07:12,660 --> 00:07:20,580
We want to type stand-by 1, preempt so that we force core 1 to become active and notice

70
00:07:20,580 --> 00:07:23,690
now that I've done that, it's become the active router.

71
00:07:24,270 --> 00:07:31,950
So Show Standby shows us that preemption is enabled and it's become the active router

72
00:07:32,280 --> 00:07:37,580
and core 2 is now the standby router and we can see that in the output here.

73
00:07:37,590 --> 00:07:38,790
So show standby.

74
00:07:39,900 --> 00:07:41,250
We can see that the active

75
00:07:41,250 --> 00:07:46,860
router is core 1 local router or local switch is the standby router.

76
00:07:47,900 --> 00:07:52,080
So don't forget to specify both a priority and preemption.

77
00:07:52,610 --> 00:07:59,210
Now, what about for VLAN 100? Show spanning tree and let's do that for VLAN 100.

78
00:07:59,930 --> 00:08:07,790
In this example, we made switch 2 the route for VLAN 100 that may have been better to make switch

79
00:08:07,790 --> 00:08:09,950
1 the route for VLAN 100

80
00:08:10,400 --> 00:08:16,940
but I simply wanted to load the VLANs across the links and we have configured Ether channel here so

81
00:08:16,940 --> 00:08:19,220
it will improve performance

82
00:08:20,360 --> 00:08:26,300
but that means we need to configure core 2 as the HSP active router.