1 00:00:01,180 --> 00:00:03,950 In this video we're going to discuss writing. 2 00:00:04,180 --> 00:00:11,260 We look at the basics of IP writing and look at different routing protocols including distance vector 3 00:00:11,650 --> 00:00:18,250 and a linked state writing protocols with compay the differences between distance vector writing protocols 4 00:00:18,250 --> 00:00:23,660 such as rip and link state running protocols such as OSPF. 5 00:00:23,800 --> 00:00:31,440 We'll also discuss some of the methods that distance vector writing protocols use to stop loops writing 6 00:00:31,450 --> 00:00:39,280 protocols are very important because they advertise networks and use various mechanisms to prevent loops 7 00:00:40,760 --> 00:00:43,890 before discussing writing protocols such as always. 8 00:00:43,910 --> 00:00:50,410 All right Joe A-P you need to know the difference between a raftered versus a routing protocol. 9 00:00:50,660 --> 00:00:58,970 You should also be able to differentiate and explain the advantages and disadvantages of using static 10 00:00:59,240 --> 00:01:02,480 routes versus dynamic running protocols. 11 00:01:02,480 --> 00:01:09,040 So why would you want to use a static route versus a dynamic writing protocol such as always B.F.. 12 00:01:09,140 --> 00:01:15,880 And as mentioned we want to talk about distance vector and link state running protocols. 13 00:01:15,940 --> 00:01:21,370 So what is the difference between a routed protocol and a rough protocol. 14 00:01:22,190 --> 00:01:26,150 Now a rotted protocol a use the data. 15 00:01:26,150 --> 00:01:31,250 Examples would be IP version 4 or IP version 6. 16 00:01:31,250 --> 00:01:40,340 When you use a Hialeah protocol such as HGP or ATP that protocol is using a lower layer protocol such 17 00:01:40,340 --> 00:01:47,560 as IP version for IP version 6 to carry the user data from one device to another. 18 00:01:47,840 --> 00:01:56,600 So when you connect to a Web site and you're viewing a web page that would be deemed to be routed data 19 00:01:57,320 --> 00:02:03,380 data from the web server is being routed to your PC. 20 00:02:03,380 --> 00:02:11,180 Now the addressing scheme used to buy routed protocols is based on the specific protocol such as IP 21 00:02:11,180 --> 00:02:17,100 version for using a 32 bit address and IP version 6 using a hundred and twenty eight. 22 00:02:17,120 --> 00:02:25,020 But address now how do routers know where devices are in a network. 23 00:02:25,400 --> 00:02:35,570 As an example my PC is based in the UK but when I go to Facebook com traffic is sent from my PC to Facebook 24 00:02:35,750 --> 00:02:39,050 based in California and back again. 25 00:02:39,050 --> 00:02:46,520 How does my device actually reach the Facebook servers in a data center in California. 26 00:02:46,520 --> 00:02:51,600 And how does the data get back to my PC in the UK. 27 00:02:51,710 --> 00:02:56,450 How is the user data forwarded from one device to another. 28 00:02:56,450 --> 00:03:05,000 Now it's important to realize that every router along the path between my PC in the UK and Facebook 29 00:03:05,000 --> 00:03:13,100 does come makes an independent routing decision as an example if I trace to Facebook dot com. 30 00:03:13,370 --> 00:03:22,770 And in this case I'm going to set the time out to a low valley such as 50 milliseconds. 31 00:03:22,850 --> 00:03:32,480 Traffic is being forwarded from my PC on a hop by hop basis from one router to the next until it hopefully 32 00:03:32,480 --> 00:03:34,980 reaches Facebook dot com. 33 00:03:35,300 --> 00:03:41,860 Every one of these hops is an independent router making independent routing decisions. 34 00:03:41,870 --> 00:03:48,360 Now Facebook and a lot of other big Web sites will have data centers scattered around the world. 35 00:03:48,530 --> 00:03:55,130 So my traffic may not actually be going all the way to the U.S. but maybe going to a local data center 36 00:03:55,220 --> 00:03:56,300 in Europe. 37 00:03:56,300 --> 00:03:59,920 That all depends on how the network is configured. 38 00:04:00,110 --> 00:04:08,630 These riding decisions made by rodders is known as the hop by hop rotting paradigm with unicast traffic 39 00:04:09,230 --> 00:04:13,720 routing is based on destination address only not on source address. 40 00:04:13,880 --> 00:04:21,560 Serratus decide which traffic goes based on the destination IP address in by example its address and 41 00:04:21,620 --> 00:04:24,580 Rodders will decide wait to route traffic. 42 00:04:24,580 --> 00:04:31,970 Based on the destination IP address and information stored in writing tables every router along the 43 00:04:31,970 --> 00:04:40,390 path needs to determine an outgoing interface to forward traffic to reach the destination IP address. 44 00:04:40,520 --> 00:04:47,220 To do that routers communicate information about networks using routing protocols. 45 00:04:47,300 --> 00:04:55,790 They will then determine the best path to the destination IP address using criteria specific to that 46 00:04:56,030 --> 00:04:58,260 individual rodding protocol. 47 00:04:58,640 --> 00:05:06,230 As an example RP uses hop count to determine the best path OSPF uses the bandwidth of interfaces to 48 00:05:06,230 --> 00:05:07,840 determine the best path. 49 00:05:08,030 --> 00:05:13,290 The GOP uses bandwidth and delay to determine the best path. 50 00:05:13,370 --> 00:05:21,290 So running protocols are used to automatically advertise networks between routers and that's how rodders 51 00:05:21,290 --> 00:05:25,790 learn about the available networks in a topology. 52 00:05:25,790 --> 00:05:32,360 It's also important to note that if a router doesn't know about a destination IP address. 53 00:05:32,360 --> 00:05:38,440 In other words information about vector destination IP address is not in its routing table. 54 00:05:38,510 --> 00:05:45,350 It will drop unicast packets destination IP addresses are matched against networks and subnets in the 55 00:05:45,350 --> 00:05:47,000 road as a writing table. 56 00:05:47,000 --> 00:05:53,600 So if a router receives traffic going to an IP address of let's say ten to one that wanted one but that 57 00:05:53,690 --> 00:05:58,610 IP address doesn't match a network in the rodders writing table. 58 00:05:58,880 --> 00:06:04,310 The Rato will drop the packets because it doesn't know where to forward them. 59 00:06:04,310 --> 00:06:11,480 Essentially if you tell Harada send traffic to IP address or tendered wondered wondered one and the 60 00:06:11,480 --> 00:06:19,460 router doesn't know how to get to that network or IP address the router will drop the traffic if there 61 00:06:19,460 --> 00:06:22,150 is no matching rot in the writing table. 62 00:06:22,310 --> 00:06:24,160 Traffic gets dropped. 63 00:06:24,170 --> 00:06:30,950 This applies specifically to unicast packets where we are doing our routing based on destination IP 64 00:06:30,950 --> 00:06:32,090 address. 65 00:06:32,090 --> 00:06:39,620 So in summary writing protocols allow Radice to learn about Destination networks that facilitates the 66 00:06:39,620 --> 00:06:44,220 exchange of a rafted information between devices. 67 00:06:44,240 --> 00:06:51,200 Routers can dynamically learn about networks in the topology and can then make routing decisions based 68 00:06:51,200 --> 00:07:00,350 on different criteria such as bandwidth hop count or delay to determine the best path route is then 69 00:07:00,350 --> 00:07:07,430 simply choose an outgoing interface based on the writing table and will then forward packets out of 70 00:07:07,670 --> 00:07:10,940 that interface to reach a destination.