Would you like to inspect the original subtitles? These are the user uploaded subtitles that are being translated: 1 00:00:00,000 --> 00:00:05,000 align:middle line:84% So now let’s look at the difference between 2 00:00:05,000 --> 00:00:08,000 align:middle line:84% a classful and a classless routing protocol. 3 00:00:08,000 --> 00:00:12,000 align:middle line:84% Firstly, classful routing protocol do not advertise 4 00:00:12,000 --> 00:00:20,000 align:middle line:84% the subnet mask as an example, they would advertise network 10.0.0.0 5 00:00:20,000 --> 00:00:24,000 align:middle line:84% but would not inform other routers of the subnet mask. 6 00:00:24,000 --> 00:00:30,000 align:middle line:84% So other routers wouldn’t know if this is a /8 or /24 mask. 7 00:00:30,000 --> 00:00:35,000 align:middle line:84% Now this becomes very important in routing because for example 8 00:00:35,000 --> 00:00:40,000 align:middle line:84% if I had a PC configured with an IP address of 10.1.1.1 9 00:00:40,000 --> 00:00:47,000 align:middle line:84% and your Pc had an IP address of 10.1.2.1 are our PCs in the same subnet? 10 00:00:47,000 --> 00:00:54,000 align:middle line:84% Well that very depends because if the subnet mask used is /8 11 00:00:54,000 --> 00:00:59,000 align:middle line:84% then our PC's are on the same subnet but if the mask used is /24 12 00:00:59,000 --> 00:01:02,000 align:middle line:84% then our PC's are not in the same subnet. 13 00:01:02,000 --> 00:01:05,000 align:middle line:84% This makes routing very difficult 14 00:01:05,000 --> 00:01:08,000 align:middle line:84% so what classful routing protocols do 15 00:01:08,000 --> 00:01:14,000 align:middle line:84% is they assume that everyone else is using the same subnet mask as they are. 16 00:01:14,000 --> 00:01:18,000 align:middle line:84% So in other words, if they received a routing update 17 00:01:18,000 --> 00:01:23,000 align:middle line:84% with a network of 10.0.0.0 on a interface 18 00:01:23,000 --> 00:01:28,000 align:middle line:84% where the IP addresses configured with /24 mask 19 00:01:28,000 --> 00:01:33,000 align:middle line:84% the router will assume that other routers will also using with /24 mask. 20 00:01:33,000 --> 00:01:38,000 align:middle line:84% Now we all know that making assumptions can be very, very dangerous. 21 00:01:38,000 --> 00:01:45,000 align:middle line:84% What this means is that routers assumed network consistency 22 00:01:45,000 --> 00:01:49,000 align:middle line:84% in other words, that the same mask is used in the network. 23 00:01:49,000 --> 00:01:53,000 align:middle line:84% The routers assume that everyone else is using the same subnet mask 24 00:01:53,000 --> 00:01:56,000 align:middle line:84% as they are and that all mask are the same. 25 00:01:56,000 --> 00:02:00,000 align:middle line:84% In other words, everyone is using a /24 mask 26 00:02:00,000 --> 00:02:05,000 align:middle line:84% that’s not scalable or deployable in networks today 27 00:02:05,000 --> 00:02:11,000 align:middle line:84% so in today's networks, we don’t use classful routing protocols such as RIP version 1. 28 00:02:11,000 --> 00:02:17,000 align:middle line:84% classful routing protocols also summarized routes across classful boundaries. 29 00:02:17,000 --> 00:02:22,000 align:middle line:84% So when you go from a class A subnet like 10.0.0.0 30 00:02:22,000 --> 00:02:27,000 align:middle line:84% to a class B subnet like 172.16.0.0 31 00:02:27,000 --> 00:02:32,000 align:middle line:84% the routers will automatically summarize all subnets to the classful boundary. 32 00:02:32,000 --> 00:02:41,000 align:middle line:84% In other words a subnet of 10.1.1.0/24 will be summarize to 10.0.0.0/8 33 00:02:41,000 --> 00:02:46,000 align:middle line:84% example of classful routing protocols include RIP version 1 and IGRP 34 00:02:46,000 --> 00:02:51,000 align:middle line:84% IGRP is no longer used and you shouldn’t be using RIP version 1. 4159