1 00:00:00,000 --> 00:00:01,740 In this lesson, we're going to explore 2 00:00:01,740 --> 00:00:04,019 the Routing Redundancy Protocols. 3 00:00:04,019 --> 00:00:06,689 Now, Routing Redundancy Protocol is a network protocol 4 00:00:06,689 --> 00:00:08,820 that prevents disruptions in communication 5 00:00:08,820 --> 00:00:12,060 by automatically rerouting data traffic in case of a path 6 00:00:12,060 --> 00:00:13,770 or device failure to help ensure 7 00:00:13,770 --> 00:00:15,480 the continuous network availability 8 00:00:15,480 --> 00:00:18,150 and reliability are going to be maintained. 9 00:00:18,150 --> 00:00:20,640 Now, while there are many routing redundancy protocols used 10 00:00:20,640 --> 00:00:23,520 in our networks, like the Hot Standby Router Protocol, 11 00:00:23,520 --> 00:00:25,350 the Virtual Router Redundancy Protocol, 12 00:00:25,350 --> 00:00:27,338 and the Gateway Load Balancing Protocol, 13 00:00:27,338 --> 00:00:30,000 all of these are typically grouped up together 14 00:00:30,000 --> 00:00:33,240 under the name of a First Hop Redundancy Protocol. 15 00:00:33,240 --> 00:00:35,130 Now, the First Hop Redundancy Protocol, 16 00:00:35,130 --> 00:00:37,050 also known as FHRP, 17 00:00:37,050 --> 00:00:38,700 is a set of protocols that are designed 18 00:00:38,700 --> 00:00:40,290 to ensure network reliability 19 00:00:40,290 --> 00:00:41,790 by providing automatic failover 20 00:00:41,790 --> 00:00:44,610 to a backup router, in case the primary router fails, 21 00:00:44,610 --> 00:00:48,030 in order for you to maintain uninterrupted network services. 22 00:00:48,030 --> 00:00:49,530 Now, let me provide you with an analogy 23 00:00:49,530 --> 00:00:51,480 to help solidify this concept. 24 00:00:51,480 --> 00:00:53,250 Let's pretend that you're driving on the highway 25 00:00:53,250 --> 00:00:54,780 and suddenly a lane is closed 26 00:00:54,780 --> 00:00:56,760 due to some ongoing construction work. 27 00:00:56,760 --> 00:00:58,920 Thankfully, your city has already been smart enough 28 00:00:58,920 --> 00:01:01,140 to provide some signs and some alternative routes, 29 00:01:01,140 --> 00:01:02,700 so you can easily navigate around 30 00:01:02,700 --> 00:01:04,769 that construction without any significant delays 31 00:01:04,769 --> 00:01:06,000 to your commute, and so you'll be able 32 00:01:06,000 --> 00:01:07,920 to arrive to work on time. 33 00:01:07,920 --> 00:01:10,560 Now, this is exactly what the First Hop Redundancy Protocols 34 00:01:10,560 --> 00:01:12,570 do for us inside of our networks, 35 00:01:12,570 --> 00:01:13,620 because they're designed to ensure 36 00:01:13,620 --> 00:01:16,020 that even if a primary path is unavailable, 37 00:01:16,020 --> 00:01:19,200 the network traffic can easily be dynamically routed over 38 00:01:19,200 --> 00:01:21,210 another path to help ensure the smooth 39 00:01:21,210 --> 00:01:22,740 and uninterrupted communications 40 00:01:22,740 --> 00:01:24,750 that are going to occur for our networks. 41 00:01:24,750 --> 00:01:26,880 The First Hop Redundancy Protocols are able 42 00:01:26,880 --> 00:01:30,090 to determine when a primary router or your first hop fails, 43 00:01:30,090 --> 00:01:32,430 and then it immediately redirects the packets 44 00:01:32,430 --> 00:01:34,110 to a standby router instead, 45 00:01:34,110 --> 00:01:35,610 and that way the communications 46 00:01:35,610 --> 00:01:37,860 will continue without any issues. 47 00:01:37,860 --> 00:01:40,320 The First Hop Redundancy Protocol is going to provide us 48 00:01:40,320 --> 00:01:43,710 with three main benefits, reliability, load balancing, 49 00:01:43,710 --> 00:01:45,540 and seamless transitions. 50 00:01:45,540 --> 00:01:47,580 First, we have reliability. 51 00:01:47,580 --> 00:01:50,820 Reliability really is the cornerstone of our network design, 52 00:01:50,820 --> 00:01:53,250 and incorporating a First Hop Redundancy Protocol 53 00:01:53,250 --> 00:01:55,350 will help to ensure that our communications remain up 54 00:01:55,350 --> 00:01:57,540 and running, even if a single router inside 55 00:01:57,540 --> 00:01:58,920 that configuration fails, 56 00:01:58,920 --> 00:02:01,320 because the First Hop Redundancy Protocol will simply 57 00:02:01,320 --> 00:02:03,660 reroute that traffic around the failed router 58 00:02:03,660 --> 00:02:05,280 inside of our networks. 59 00:02:05,280 --> 00:02:07,320 Second, we have load balancing. 60 00:02:07,320 --> 00:02:09,060 Now, the First Hop Redundancy Protocol 61 00:02:09,060 --> 00:02:11,430 not only helps when a router fails completely, 62 00:02:11,430 --> 00:02:12,630 but can also be configured 63 00:02:12,630 --> 00:02:15,510 to distribute your network traffic across multiple routers 64 00:02:15,510 --> 00:02:17,670 in order to prevent a single device from becoming 65 00:02:17,670 --> 00:02:19,410 overwhelmed with too much traffic. 66 00:02:19,410 --> 00:02:21,510 And this in turn will increase the efficiency 67 00:02:21,510 --> 00:02:23,430 of our network communications. 68 00:02:23,430 --> 00:02:25,710 Third, we have seamless transitions. 69 00:02:25,710 --> 00:02:28,200 The First Hop Redundancy Protocol is designed to ensure 70 00:02:28,200 --> 00:02:31,260 that data always continues to flow properly by making quick 71 00:02:31,260 --> 00:02:33,570 and seamless transitions from sending data 72 00:02:33,570 --> 00:02:36,000 to one failed router over by redirecting it 73 00:02:36,000 --> 00:02:39,240 to a standby router instead, when the router fails. 74 00:02:39,240 --> 00:02:41,790 This all happens seamlessly without your end users even 75 00:02:41,790 --> 00:02:44,460 being aware of it, and this in turn leads to a better 76 00:02:44,460 --> 00:02:46,770 and more reliable user experience. 77 00:02:46,770 --> 00:02:49,590 Now, to make the First Hop Router Redundancy Protocol work, 78 00:02:49,590 --> 00:02:51,870 we're going to rely on two critical components, 79 00:02:51,870 --> 00:02:55,140 and these are the Virtual IP and the Subinterface. 80 00:02:55,140 --> 00:02:57,360 Now, a Virtual IP is an IP address 81 00:02:57,360 --> 00:02:59,490 that is not bound to a specific device, 82 00:02:59,490 --> 00:03:02,130 but instead is going to be serving as a representative 83 00:03:02,130 --> 00:03:05,280 for one or more devices inside of our network. 84 00:03:05,280 --> 00:03:07,710 Now, in the First Hop Redundancy Protocol, 85 00:03:07,710 --> 00:03:10,140 we're going to have the Virtual IP address as an address 86 00:03:10,140 --> 00:03:11,790 that the devices in the network are going to use 87 00:03:11,790 --> 00:03:13,560 as their default gateway. 88 00:03:13,560 --> 00:03:15,030 This means that no matter which 89 00:03:15,030 --> 00:03:17,460 of your physical routers is actively routing the packets 90 00:03:17,460 --> 00:03:19,650 at any given time, your network devices 91 00:03:19,650 --> 00:03:21,780 are always going to continue to send their packets 92 00:03:21,780 --> 00:03:24,300 to this unchanging Virtual IP instead, 93 00:03:24,300 --> 00:03:27,000 to ensure a smooth and uninterrupted network experience, 94 00:03:27,000 --> 00:03:29,010 because the First Hop Redundancy Protocol 95 00:03:29,010 --> 00:03:31,800 will then reroute the traffic from that Virtual IP 96 00:03:31,800 --> 00:03:34,920 to the primary or secondary router based on which one is up 97 00:03:34,920 --> 00:03:37,980 and available to handle your routing needs at that time. 98 00:03:37,980 --> 00:03:39,720 Now, a Subinterface on the other hand, 99 00:03:39,720 --> 00:03:42,300 is designed to allow a single physical interface on a router 100 00:03:42,300 --> 00:03:46,020 or switch to be subdivided into multiple logical interfaces. 101 00:03:46,020 --> 00:03:48,810 Each Subinterface can be configured independently, 102 00:03:48,810 --> 00:03:50,760 and each one can belong to different VLANs 103 00:03:50,760 --> 00:03:52,590 with its own separate security policies 104 00:03:52,590 --> 00:03:53,970 being attached to it. 105 00:03:53,970 --> 00:03:56,490 This allows each Subinterface to have more autonomy 106 00:03:56,490 --> 00:03:57,960 and to provide you with the ability 107 00:03:57,960 --> 00:03:59,670 to provide more specific controls 108 00:03:59,670 --> 00:04:02,100 to each of your Subinterfaces. 109 00:04:02,100 --> 00:04:03,900 Subinterfaces are cost efficient, 110 00:04:03,900 --> 00:04:05,190 and they help us when we're conducting 111 00:04:05,190 --> 00:04:06,810 traffic management too. 112 00:04:06,810 --> 00:04:09,540 This is because our Subinterfaces allow us to segment 113 00:04:09,540 --> 00:04:11,340 and manage our networks without the need 114 00:04:11,340 --> 00:04:12,630 for additional physical hardware. 115 00:04:12,630 --> 00:04:14,520 And this in turn is going to help 116 00:04:14,520 --> 00:04:16,110 to ensure a smoother data flow 117 00:04:16,110 --> 00:04:18,420 and a more enhanced security posture. 118 00:04:18,420 --> 00:04:20,730 Now, there are three main protocols that are considered 119 00:04:20,730 --> 00:04:23,130 to be First Hop Redundancy Protocols. 120 00:04:23,130 --> 00:04:25,620 These are known as the Hot Standby Router Protocol, 121 00:04:25,620 --> 00:04:27,540 the Virtual Router Redundancy Protocol, 122 00:04:27,540 --> 00:04:29,880 and the Gateway Load Balancing Protocol. 123 00:04:29,880 --> 00:04:32,820 First, we have the Hot Standby Router Protocol. 124 00:04:32,820 --> 00:04:34,350 The Hot Standby Router Protocol, 125 00:04:34,350 --> 00:04:37,110 or HSRP, was first developed by Cisco 126 00:04:37,110 --> 00:04:38,580 as a redundancy protocol 127 00:04:38,580 --> 00:04:40,770 that can establish a fault tolerant default gateway 128 00:04:40,770 --> 00:04:43,530 for your devices on a local network segment. 129 00:04:43,530 --> 00:04:46,740 HSRP enables two or more routers to work together 130 00:04:46,740 --> 00:04:48,570 by presenting the underlying devices 131 00:04:48,570 --> 00:04:49,920 as a single virtual router 132 00:04:49,920 --> 00:04:52,440 to the host on your local area network. 133 00:04:52,440 --> 00:04:55,500 Inside of a Hot Standby Router Protocol configuration, 134 00:04:55,500 --> 00:04:58,050 one router will be elected as the active router, 135 00:04:58,050 --> 00:04:59,190 and it's going to be expected to handle 136 00:04:59,190 --> 00:05:01,500 all the network's routing responsibilities. 137 00:05:01,500 --> 00:05:04,260 While another one is designed as the standby router, 138 00:05:04,260 --> 00:05:05,520 and it's going to wait to take over 139 00:05:05,520 --> 00:05:08,370 at any time the active router fails in the future. 140 00:05:08,370 --> 00:05:10,650 This transition will be seamless to your users, 141 00:05:10,650 --> 00:05:11,483 and it helps to ensure 142 00:05:11,483 --> 00:05:13,542 that minimum packet loss is going to be experienced 143 00:05:13,542 --> 00:05:16,920 and that you don't have uninterrupted network services. 144 00:05:16,920 --> 00:05:19,080 The Hot Standby Router Protocol also provides 145 00:05:19,080 --> 00:05:21,030 a special feature known as preempting. 146 00:05:21,030 --> 00:05:22,770 This is where a higher priority router 147 00:05:22,770 --> 00:05:25,620 can take over as the active router if it comes online 148 00:05:25,620 --> 00:05:27,900 after the initial election was made. 149 00:05:27,900 --> 00:05:31,140 Second, we have the Virtual Router Redundancy Protocol. 150 00:05:31,140 --> 00:05:33,150 The Virtual Router Redundancy Protocol, 151 00:05:33,150 --> 00:05:34,980 also known as VRRP, 152 00:05:34,980 --> 00:05:37,890 is a standard redundancy protocol that functions similarly 153 00:05:37,890 --> 00:05:39,900 to the Hot Standby Router Protocol, 154 00:05:39,900 --> 00:05:43,080 but there are a few key differences you should be aware of. 155 00:05:43,080 --> 00:05:46,110 VRRP is considered to be an open standard, 156 00:05:46,110 --> 00:05:49,230 unlike the more proprietary format of HSRP 157 00:05:49,230 --> 00:05:50,940 that was developed by Cisco. 158 00:05:50,940 --> 00:05:53,760 This means that since VRRP is an open standard, 159 00:05:53,760 --> 00:05:55,770 it is not tied to a specific vendor, 160 00:05:55,770 --> 00:05:56,940 and this allows for higher levels 161 00:05:56,940 --> 00:05:59,130 of compatibility across multiple different brands 162 00:05:59,130 --> 00:06:00,120 of networking equipment. 163 00:06:00,120 --> 00:06:03,930 VRRP also enables the configuration of multiple routers 164 00:06:03,930 --> 00:06:06,870 to act as a single virtual router with one designated 165 00:06:06,870 --> 00:06:09,990 as the primary router and the other serving as backups. 166 00:06:09,990 --> 00:06:11,610 If the primary router fails, 167 00:06:11,610 --> 00:06:13,650 one of the backups will automatically take over 168 00:06:13,650 --> 00:06:15,300 the primary router's role to ensure 169 00:06:15,300 --> 00:06:17,640 that the network's default gateway remains available 170 00:06:17,640 --> 00:06:19,650 to the hosts on that network. 171 00:06:19,650 --> 00:06:22,410 The Virtual Router Redundancy Protocol also provides us 172 00:06:22,410 --> 00:06:24,570 with a simple and automatic election scheme 173 00:06:24,570 --> 00:06:26,580 that doesn't require any additional configuration 174 00:06:26,580 --> 00:06:28,830 on the end user's devices too. 175 00:06:28,830 --> 00:06:31,920 Third, we have the Gateway Load Balancing Protocol. 176 00:06:31,920 --> 00:06:35,580 The Gateway Load Balancing Protocol, also known as GLBP, 177 00:06:35,580 --> 00:06:37,590 is another Cisco developed protocol 178 00:06:37,590 --> 00:06:39,510 that takes redundancy a step further 179 00:06:39,510 --> 00:06:42,330 by adding load balancing capabilities into our mix. 180 00:06:42,330 --> 00:06:46,590 Like HSRP and VRRP, the Gateway Load Balancing Protocol 181 00:06:46,590 --> 00:06:49,290 is designed to allow multiple routers to provide redundancy 182 00:06:49,290 --> 00:06:50,640 for the virtual IP address 183 00:06:50,640 --> 00:06:52,500 that's assigned to the group of routers. 184 00:06:52,500 --> 00:06:55,230 However, GLBP is uniquely designed 185 00:06:55,230 --> 00:06:56,640 so that all of your configured routers 186 00:06:56,640 --> 00:06:58,710 can simultaneously forward packet 187 00:06:58,710 --> 00:07:01,050 in order to effectively distribute the traffic load 188 00:07:01,050 --> 00:07:03,330 amongst all the routers in the group. 189 00:07:03,330 --> 00:07:04,410 This is achieved by assigning 190 00:07:04,410 --> 00:07:08,130 a different Virtual MAC address to each GLBP group member, 191 00:07:08,130 --> 00:07:10,680 and the GLBP active virtual gateway will 192 00:07:10,680 --> 00:07:12,870 then assign each of these addresses to clients, 193 00:07:12,870 --> 00:07:14,970 so that multiple routers can share the traffic load 194 00:07:14,970 --> 00:07:17,100 being handled on a given network. 195 00:07:17,100 --> 00:07:19,410 The Gateway Load Balancing Protocol is great 196 00:07:19,410 --> 00:07:21,990 at load balancing, of course, but it also does provide us 197 00:07:21,990 --> 00:07:25,920 with redundancy like HSRP and VRRP do. 198 00:07:25,920 --> 00:07:28,260 This is because the Gateway Load Balancing Protocol 199 00:07:28,260 --> 00:07:29,760 will automatically redirect traffic 200 00:07:29,760 --> 00:07:31,470 to other routers inside of the group 201 00:07:31,470 --> 00:07:33,270 if any of those routers fail. 202 00:07:33,270 --> 00:07:35,850 And this helps to ensure continuous network availability 203 00:07:35,850 --> 00:07:38,910 while also optimizing our network's resource utilization. 204 00:07:38,910 --> 00:07:41,130 So remember, routing redundancy protocols 205 00:07:41,130 --> 00:07:42,030 are designed to provide us 206 00:07:42,030 --> 00:07:44,520 with network reliability and efficiency. 207 00:07:44,520 --> 00:07:46,080 Routing redundancy protocols 208 00:07:46,080 --> 00:07:48,270 like the Hot Standby Router Protocol, 209 00:07:48,270 --> 00:07:50,190 the Virtual Router Redundancy Protocol, 210 00:07:50,190 --> 00:07:52,320 and the Gateway Load Balancing Protocol 211 00:07:52,320 --> 00:07:54,480 are all going to work behind the scenes to ensure 212 00:07:54,480 --> 00:07:56,700 that the data flow within our network will continue 213 00:07:56,700 --> 00:07:58,740 to run even if a single router fails 214 00:07:58,740 --> 00:08:01,020 during our daily network operations. 215 00:08:01,020 --> 00:08:02,610 As we continue to depend on our networks 216 00:08:02,610 --> 00:08:04,500 for everything from global communications 217 00:08:04,500 --> 00:08:06,540 to streaming our favorite television shows, 218 00:08:06,540 --> 00:08:09,270 ensuring router redundancy is really a critical aspect 219 00:08:09,270 --> 00:08:11,310 of our network designs for both our home 220 00:08:11,310 --> 00:08:12,783 and office networks.