1 1 00:00:00,730 --> 00:00:03,580 Network availability, in this section of the course, 2 2 00:00:03,580 --> 00:00:05,890 we're going to talk about network availability. 3 3 00:00:05,890 --> 00:00:07,690 Now, network availability is a measure 4 4 00:00:07,690 --> 00:00:10,650 of how well a computer network can respond to connectivity 5 5 00:00:10,650 --> 00:00:13,420 and performance demands that are being placed upon it. 6 6 00:00:13,420 --> 00:00:15,410 This is usually going to be quantitatively measured 7 7 00:00:15,410 --> 00:00:17,590 as uptime, where we count the amount of time 8 8 00:00:17,590 --> 00:00:18,630 the network was up, 9 9 00:00:18,630 --> 00:00:20,500 and divide that by the total amount of time 10 10 00:00:20,500 --> 00:00:22,310 covered by the monitoring period. 11 11 00:00:22,310 --> 00:00:25,330 For example, if I monitor the network for a full year 12 12 00:00:25,330 --> 00:00:27,930 and I only had five minutes and 16 seconds of downtime 13 13 00:00:27,930 --> 00:00:32,930 during that year, this would equate to an uptime of 99.999%. 14 14 00:00:33,070 --> 00:00:35,760 Now this is known as the five nines of availability. 15 15 00:00:35,760 --> 00:00:37,320 And it's considered the gold standard 16 16 00:00:37,320 --> 00:00:38,760 in network availability. 17 17 00:00:38,760 --> 00:00:40,790 This is considered to be an extremely available 18 18 00:00:40,790 --> 00:00:42,290 and high quality network, 19 19 00:00:42,290 --> 00:00:44,500 but there is going to be downtime in your networks. 20 20 00:00:44,500 --> 00:00:47,800 It's a fact of life, devices fail, connections go down, 21 21 00:00:47,800 --> 00:00:50,840 and incorrect configurations are sometimes going to be applied. 22 22 00:00:50,840 --> 00:00:53,070 There are a lot of reasons that downtime occurs, 23 23 00:00:53,070 --> 00:00:55,430 but our goal is to minimize that downtime 24 24 00:00:55,430 --> 00:00:57,560 and increase our availability. 25 25 00:00:57,560 --> 00:00:59,960 In order to reach the highest levels of availability, 26 26 00:00:59,960 --> 00:01:02,130 we need to build in availability and redundancy 27 27 00:01:02,130 --> 00:01:04,070 into our networks from the beginning. 28 28 00:01:04,070 --> 00:01:05,780 We also are going to use quality of service 29 29 00:01:05,780 --> 00:01:08,290 to ensure that our end-users are happy with the networks 30 30 00:01:08,290 --> 00:01:10,180 and the services that we're providing them. 31 31 00:01:10,180 --> 00:01:12,400 So in this section on network availability, 32 32 00:01:12,400 --> 00:01:14,660 we're really going to focus on two domains. 33 33 00:01:14,660 --> 00:01:16,020 We're going to see domain two, 34 34 00:01:16,020 --> 00:01:17,400 which is network implementations, 35 35 00:01:17,400 --> 00:01:19,740 and domain three, network operations. 36 36 00:01:19,740 --> 00:01:21,820 In here, we're going to talk about two objectives. 37 37 00:01:21,820 --> 00:01:24,830 Objective 2.2 and objective 3.3. 38 38 00:01:24,830 --> 00:01:27,750 Now objective 2.2 states, that you must compare and contrast 39 39 00:01:27,750 --> 00:01:30,670 routing technologies and bandwidth management concepts. 40 40 00:01:30,670 --> 00:01:32,240 Objective 3.3 states, 41 41 00:01:32,240 --> 00:01:33,920 that you must explain high availability 42 42 00:01:33,920 --> 00:01:35,470 and disaster recovery concepts 43 43 00:01:35,470 --> 00:01:37,860 and summarize which is the best solution. 44 44 00:01:37,860 --> 00:01:39,260 So let's get started talking 45 45 00:01:39,260 --> 00:01:40,710 all about the different ways for us 46 46 00:01:40,710 --> 00:01:42,900 to increase the availability, reliability, 47 47 00:01:42,900 --> 00:01:44,850 and quality of service within our networks 48 48 00:01:44,850 --> 00:01:46,350 in this section of the course. 49 49 00:01:47,390 --> 00:01:49,743 (ethereal music)