1
00:00:00,000 --> 00:00:10,000
So here’s switch 2, enable conf t int vlan 10 standby

2
00:00:10,000 --> 00:00:16,000
now it’s important that the same group number be used on both sides

3
00:00:16,000 --> 00:00:21,000
otherwise, we'll have 2 active routers in different groups

4
00:00:21,000 --> 00:00:25,000
and you'd want to do that if you want to split the load

5
00:00:25,000 --> 00:00:29,000
within a VLAN and use 2 separate IP addresses.

6
00:00:29,000 --> 00:00:31,000
but We won’t be doing that right now

7
00:00:31,000 --> 00:00:33,000
we wanted the election to take place

8
00:00:33,000 --> 00:00:37,000
between this 2 switches for the same virtual router.

9
00:00:37,000 --> 00:00:40,000
So we're going to specify IP address

10
00:00:40,000 --> 00:00:44,000
and the IP address in our case is 10.1.10.254

11
00:00:44,000 --> 00:00:48,000
we can now hit carriage return

12
00:00:48,000 --> 00:00:58,000
and we won’t change the priority by default, it is 100

13
00:00:58,000 --> 00:01:02,000
so if we configure that again as 100

14
00:01:02,000 --> 00:01:07,000
and type do sh run int vlan 10

15
00:01:07,000 --> 00:01:10,000
you’ll notice that the priority doesn’t display

16
00:01:10,000 --> 00:01:12,000
because that’s the default once again.

17
00:01:12,000 --> 00:01:15,000
So all I need to configure is that command

18
00:01:15,000 --> 00:01:18,000
and now when we type show standby

19
00:01:18,000 --> 00:01:25,000
we can see that for group 1 on VLAN 10

20
00:01:25,000 --> 00:01:28,000
the local router is the standby router

21
00:01:28,000 --> 00:01:31,000
the virtual IP address is 10.1.10.254

22
00:01:31,000 --> 00:01:35,000
that’s the virtual HSRP router that’s been configured.

23
00:01:35,000 --> 00:01:37,000
There’s the virtual MAC address

24
00:01:37,000 --> 00:01:43,000
hello and hold time are set to the defaults, make sure that you set them the same

25
00:01:43,000 --> 00:01:47,000
if you do change them, so make sure that it’s the same on both routers.

26
00:01:47,000 --> 00:01:50,000
Preemption is disabled in this example

27
00:01:50,000 --> 00:01:55,000
the active router is 10.1.10.1 and the priority is 200

28
00:01:55,000 --> 00:01:59,000
in other words, switch 1 is the active router

29
00:01:59,000 --> 00:02:04,000
and has a priority of 200, the local router is the standby router

30
00:02:04,000 --> 00:02:08,000
and has a default priority of 100.

31
00:02:08,000 --> 00:02:10,000
Back on switch 1  show standby

32
00:02:10,000 --> 00:02:13,000
shows us that the router is still active

33
00:02:13,000 --> 00:02:19,000
so the local router is active but the standby router of 10.1.10.2

34
00:02:19,000 --> 00:02:24,000
in other words, switch 2 is now shown with its priority of 100.

35
00:02:24,000 --> 00:02:30,000
So that’s how you configure basic HSRP

36
00:02:30,000 --> 00:02:34,000
on the active router, we've configured this

37
00:02:34,000 --> 00:02:38,000
and on the standby router, we only configure a single command.

38
00:02:38,000 --> 00:02:44,000
Now once we’ve done that on router 1, which is acting as our PC

39
00:02:44,000 --> 00:02:49,000
let’s see if we can ping the virtual router.

40
00:02:49,000 --> 00:02:52,000
So ping 10.1.10.254 the ping works

41
00:02:52,000 --> 00:03:00,000
and if I type sh arp IP address of virtual router, MAC address of virtual router.

42
00:03:00,000 --> 00:03:05,000
Now this thing doesn’t exist at the moment even if I turn that off.

43
00:03:05,000 --> 00:03:10,000
This router isn’t physically connected to our topology on GNS3 at all

44
00:03:10,000 --> 00:03:14,000
I’m only showing the icon here to show how it fits in the topology.

45
00:03:14,000 --> 00:03:17,000
So it’s not on, it's not physically connected anywhere

46
00:03:17,000 --> 00:03:24,000
but router 1 acting as PC 1 is able to ping that IP address

47
00:03:24,000 --> 00:03:27,000
because in actual fact it’s pinging switch 1

48
00:03:27,000 --> 00:03:32,000
so on switch 1, we can use the debug, debug ip icmp

49
00:03:32,000 --> 00:03:40,000
go back into router 1 and notice were getting output

50
00:03:40,000 --> 00:03:47,000
on the console of switch 1, its sending an echo reply back to 10.1.10.11

51
00:03:47,000 --> 00:03:55,000
which is router 1 acting as PC 1 from a source IP address of 10.1.10.254

52
00:03:55,000 --> 00:04:04,000
the virtual router's IP address so debug ip icmp on router 1 acting as our PC

53
00:04:04,000 --> 00:04:11,000
notice this PC believes that it's talking to this IP address

54
00:04:11,000 --> 00:04:15,000
and it believes its talking to this MAC address

55
00:04:15,000 --> 00:04:19,000
whereas in actual fact it's communicating with switch 1.

56
00:04:19,000 --> 00:04:23,000
Now before we run a test and test fail over

57
00:04:23,000 --> 00:04:27,000
we need to configure HSRP on VLAN 20

58
00:04:27,000 --> 00:04:29,000
and then we'll be able to test connectivity

59
00:04:29,000 --> 00:04:31,000
between router 1 and router 2

60
00:04:31,000 --> 00:04:35,000
and then verify what happens when an interface goes down

61
00:04:35,000 --> 00:04:39,000
I'll turn off debugging on switch 1

62
00:04:39,000 --> 00:04:44,000
go into VLAN 20 standby group number

63
00:04:44,000 --> 00:04:46,000
I’m going to specify 1 to show you

64
00:04:46,000 --> 00:04:50,000
that you can use the same group number in different VLANs

65
00:04:50,000 --> 00:04:52,000
but these are separated from each other

66
00:04:52,000 --> 00:04:54,000
because they're in different VLANs

67
00:04:54,000 --> 00:04:59,000
IP address 10.1.20.254 in this example

68
00:04:59,000 --> 00:05:02,000
so VLAN 20 virtual IP address

69
00:05:02,000 --> 00:05:06,000
that's all that I’m going to configure on switch 1

70
00:05:06,000 --> 00:05:13,000
I’d like to show you how preemption works

71
00:05:13,000 --> 00:05:15,000
so I’m going to wait a while

72
00:05:15,000 --> 00:05:18,000
so that this router can become the active router

73
00:05:18,000 --> 00:05:21,000
and then I'll enable preemption on switch 2

74
00:05:21,000 --> 00:05:26,000
to show you that it forces itself to become the active router

75
00:05:26,000 --> 00:05:29,000
for that VLAN when we enable preemption.

76
00:05:29,000 --> 00:05:33,000
So the status speak it did change to active

77
00:05:33,000 --> 00:05:36,000
but this output is when it was still in the speak stage.

78
00:05:36,000 --> 00:05:40,000
So active router is unknown, standby router is unknown

79
00:05:40,000 --> 00:05:45,000
local priority is 100, active virtual MAC address is unknown

80
00:05:45,000 --> 00:05:48,000
but when we do show standby again

81
00:05:48,000 --> 00:05:53,000
local router is now active, standby router is unknown

82
00:05:53,000 --> 00:05:58,000
so active router is the local router using this MAC address.

83
00:05:58,000 --> 00:06:02,000
So it’s the same MAC address on VLAN 10 and VLAN  20

84
00:06:02,000 --> 00:06:04,000
but it doesn’t cause a conflict

85
00:06:04,000 --> 00:06:08,000
because MAC address is on layer 2 addresses

86
00:06:08,000 --> 00:06:11,000
and are contained within the relevant VLAN

87
00:06:11,000 --> 00:06:14,000
so show run interface vlan 20

88
00:06:14,000 --> 00:06:19,000
that’s the config of a HSRP on switch 1 for VLAN 20

89
00:06:19,000 --> 00:06:24,000
on switch 2 now, int vlan 20

90
00:06:24,000 --> 00:06:38,000
standby group number 1  IP 10.1.20.254 standby 1 priority 200

91
00:06:38,000 --> 00:06:43,000
so let’s see if it forces itself to become active

92
00:06:43,000 --> 00:06:47,000
without the preemption keyword

93
00:06:47,000 --> 00:06:52,000
so do show standby preemption is currently disabled

94
00:06:52,000 --> 00:06:56,000
it’s in the speak state and just gone to standby

95
00:06:56,000 --> 00:07:03,000
so notice even though this router has a higher priority of 200

96
00:07:03,000 --> 00:07:06,000
the active router remains the active router

97
00:07:06,000 --> 00:07:09,000
because we haven’t put the preempt keyword in

98
00:07:09,000 --> 00:07:13,000
to force this router to become the active router

99
00:07:13,000 --> 00:07:19,000
we use the command standby 1 preempt

100
00:07:19,000 --> 00:07:25,000
and what we should see and it just happened over there.

101
00:07:25,000 --> 00:07:28,000
Notice state change to active

102
00:07:28,000 --> 00:07:33,000
so for VLAN 20 group 1 the state just changed

103
00:07:33,000 --> 00:07:36,000
and we can see that in the output.

104
00:07:36,000 --> 00:07:39,000
Do the show standby command again

105
00:07:39,000 --> 00:07:43,000
notice the local router is the active router for VLAN 20

106
00:07:43,000 --> 00:07:47,000
group 1 and the standby router is switch 1

107
00:07:47,000 --> 00:07:53,000
we can see as an example, that state change on switch 1

108
00:07:53,000 --> 00:07:57,000
so preemption forces the local switch in this example

109
00:07:57,000 --> 00:08:01,000
to be the active router for VLAN 20.

110
00:08:01,000 --> 00:08:05,000
So what have we done, switch 1 is the active router for VLAN 10

111
00:08:05,000 --> 00:08:10,000
switch 2 is the active router for VLAN 20

112
00:08:10,000 --> 00:08:14,000
we have configured HSRP on both VLANs in this example

113
00:08:14,000 --> 00:08:19,000
so the next step is to configure the default gateways on the PC's

114
00:08:19,000 --> 00:08:24,000
and then test connectivity when an interface goes down.