1 00:00:17,730 --> 00:00:20,920 OK, so let's see if we can complete this lab together. 2 00:00:21,570 --> 00:00:26,160 The first thing we need to do is configure and optimize HSRP. 3 00:00:31,330 --> 00:00:40,210 That means that we are going to configure HSRP on the core switch as in the topology, core 1 and core 4 00:00:40,210 --> 00:00:40,750 2. 5 00:00:48,320 --> 00:00:56,600 Core 1 and Core 2 are the switches that are configured with inter VLAN routing, as well as layer 6 00:00:56,600 --> 00:01:00,390 3 IP addresses for the various VLANs. 7 00:01:01,280 --> 00:01:06,680 In other words, they have these SVIs or switched virtual interfaces configured. 8 00:01:08,510 --> 00:01:12,680 So they're going to be used as the default gateway for the PCs. 9 00:01:14,290 --> 00:01:20,260 Now, we could configure the PCs to use switch 1 as their default gateway 10 00:01:21,360 --> 00:01:24,630 or they could use switch 2 as their default gateway. 11 00:01:25,700 --> 00:01:31,430 In other words, we could configure PCs in VLAN 10 to use this IP address as the default gateway 12 00:01:31,970 --> 00:01:37,110 and perhaps for devices in VLAN 20 this IP address as the default gateway. 13 00:01:37,940 --> 00:01:45,260 The problem with that is if this PC has core 1 configured as its default gateway and core 1 14 00:01:45,260 --> 00:01:53,660 goes down, PCs and VLAN 10 will no longer be able to connect to devices and other VLANs because their 15 00:01:53,660 --> 00:01:55,550 default gateway has gone down. 16 00:01:55,940 --> 00:02:03,680 So the idea with HSRP or hot standby routing protocol and other protocols such as VRRP or Virtual 17 00:02:03,680 --> 00:02:12,710 Router Redundancy Protocol and GLBP or Gateway Load Balancing Protocol is that they create a virtual 18 00:02:12,740 --> 00:02:15,470 router or virtual default gateway. 19 00:02:15,980 --> 00:02:22,310 So the idea is you run these protocols on the core switches and a virtual router or virtual default 20 00:02:22,310 --> 00:02:25,280 gateway is created for the PCs. 21 00:02:25,970 --> 00:02:32,480 If one of the core physical devices goes down, it's not a problem because the other physical device 22 00:02:32,480 --> 00:02:36,270 will do the routing on behalf of that virtual router. 23 00:02:36,710 --> 00:02:45,170 So we want to configure HSRP on these two core routers so that we have redundancy in case one of the physical 24 00:02:45,170 --> 00:02:46,220 routers goes down. 25 00:02:47,180 --> 00:02:51,550 PCs will still be able to use their virtual default gateway. 26 00:02:52,100 --> 00:03:02,300 So on core 1 let's start with VLAN 10 the command to use is standby and you specify a number 27 00:03:02,840 --> 00:03:11,530 you can do load sharing of traffic within a VLAN by using multiple group numbers. For the CCNA course 28 00:03:11,540 --> 00:03:14,210 however, we're just going to use one group 29 00:03:14,210 --> 00:03:22,120 number, the group number could be the same number as your VLAN number, but it doesn't have to be. 30 00:03:22,520 --> 00:03:28,940 I'm simply going to use group number one on all the VLANs to show you that the group number is 31 00:03:28,940 --> 00:03:31,940 not specific to a VLAN, group 32 00:03:31,940 --> 00:03:33,550 numbers can be in this range. 33 00:03:34,310 --> 00:03:42,170 So we type a standby group number 1, IP because we want to have HSRP configured for IPv4 34 00:03:42,800 --> 00:03:45,380 and we specify a virtual IP address. 35 00:03:49,100 --> 00:03:58,580 Now in this example, we want to optimize HSRP that means that we want core 1 to be the HSRP 36 00:03:58,610 --> 00:04:05,450 active router for VLANs where it is the spanning-tree root. Notice for this VLAN 37 00:04:05,450 --> 00:04:10,850 it's become active because there's no other router or switch configured for HSRP. 38 00:04:11,870 --> 00:04:18,430 But the idea is the switch is the spanning-tree root for VLANs 1, 10 and 30. 39 00:04:19,029 --> 00:04:24,200 We are going to want it to be the HSRP primary for those VLANs. 40 00:04:24,800 --> 00:04:33,080 We don't want this switch to be the HSRP primary or active router for VLAN 10 because it means that traffic 41 00:04:33,080 --> 00:04:37,250 will traverse across these links to get to the default gateway. 42 00:04:37,970 --> 00:04:44,840 And in the same way, we don't want switch 1 to be the HSRP active router when switch 2 is the spanning 43 00:04:44,840 --> 00:04:53,450 tree root for VLAN 20 because traffic would have to traverse this way to get to the HSRP default gateway. 44 00:04:54,460 --> 00:05:04,960 So hence, we are going to match HSRP active routers to VLANs and a way to ensure that is to change 45 00:05:05,050 --> 00:05:12,730 the priority of the active router the higher the priority, the more likely that that router or switch will 46 00:05:12,730 --> 00:05:16,660 become the HSRP active forwarder or active router. 47 00:05:17,890 --> 00:05:27,910 Default priority is 100, stand by one preempt allows us to force this switch to become the HSRP active 48 00:05:27,910 --> 00:05:29,230 router when it's up. 49 00:05:29,890 --> 00:05:36,730 So as an example, if it went down, so you turn off core 1, core 2 would become the HSRP active 50 00:05:36,730 --> 00:05:37,120 router 51 00:05:37,360 --> 00:05:39,160 while core 1 is down 52 00:05:39,670 --> 00:05:47,560 but when you turn on core 1 and it boots up again, preemption will force it to become the HSRP active 53 00:05:47,560 --> 00:05:48,570 router once again. 54 00:05:49,210 --> 00:05:49,810 So show 55 00:05:49,820 --> 00:05:50,550 standby 56 00:05:52,130 --> 00:05:55,190 we can see that we've got a group configured on VLAN 10. 57 00:05:56,140 --> 00:06:04,320 State is active, a virtual IP address is this, virtual Mac address is this, now this is the HSRP well 58 00:06:04,330 --> 00:06:05,400 known Mac address. 59 00:06:06,130 --> 00:06:12,280 This is the group number, group number is 1 because we created a group of one. 60 00:06:13,440 --> 00:06:20,120 This is a hexadecimal number, if we had created Group 10, the Mac address would have ended in 0A, 61 00:06:20,350 --> 00:06:22,800 A being hexadecimal for 10. 62 00:06:23,310 --> 00:06:29,310 If we had created group 11, it would have been AB, B being hexadecimal for 11. 63 00:06:30,290 --> 00:06:37,850 Active router is the local router preemption is enabled standby, router is not known yet we haven't configured 64 00:06:37,940 --> 00:06:41,720 switch 2, so switch 1 doesn't know about another 65 00:06:41,930 --> 00:06:45,440 HSRP router, priority is 200. 66 00:06:46,800 --> 00:06:55,170 On this side, if we type show stand by, we see nothing because we haven't configured HSRP on the 67 00:06:55,170 --> 00:07:02,490 switch yet, so on the same VLAN, VLAN 10, standby, make sure that you use the same number on both 68 00:07:02,490 --> 00:07:03,120 sides. 69 00:07:03,600 --> 00:07:06,440 IP same IP address. 70 00:07:07,740 --> 00:07:10,020 In other words, same virtual IP address. 71 00:07:11,000 --> 00:07:13,630 Now, we could specify a priority here. 72 00:07:16,270 --> 00:07:23,110 We don't need to because the default is already 100 but if we type show run and have a look at 73 00:07:23,230 --> 00:07:26,230 the configuration on VLAN 74 00:07:28,630 --> 00:07:36,670 10 notice the property is not displayed because it's the default priority the router has become a 75 00:07:36,670 --> 00:07:37,440 standby. 76 00:07:38,020 --> 00:07:42,620 I just hope he goes through different states and the state is standby. 77 00:07:43,060 --> 00:07:46,960 So show standby shows us that for this group. 78 00:07:48,630 --> 00:07:50,580 The local switch is a standby switch. 79 00:07:52,560 --> 00:07:54,080 Do the command again here. 80 00:07:55,500 --> 00:07:58,050 Switch 1 or core 1 is the active router, 81 00:07:59,240 --> 00:08:06,740 core 2 is the standby router or standby switch, it's a layer 3 switch but it's acting like a router. 82 00:08:08,390 --> 00:08:14,600 So forgive me if I use the terms interchangeably, a virtual IP address is that notice Mac address is 83 00:08:14,600 --> 00:08:20,270 the same, standby router is the local router, active router is core 84 00:08:20,270 --> 00:08:22,190 1 priority is this, 85 00:08:22,190 --> 00:08:23,180 that is the default. 86 00:08:24,370 --> 00:08:31,720 On this side, we've got an active router being the local router and it's now learnt about core 2 being 87 00:08:31,720 --> 00:08:32,919 the standby router.