WEBVTT 00:07.710 --> 00:16.470 Whenever your 48 is deployed in net mode in network address translation mode it acts as an OS I layer 00:16.470 --> 00:20.680 3 router as a router it does. 00:20.700 --> 00:31.680 Decisions decisions on where to send different packets that arrives 2 or different packets that it generates. 00:31.690 --> 00:41.250 Note it does so using a routing table routing table is actually a series of rules. 00:41.250 --> 00:44.910 Think of each rule as the next hope. 00:45.750 --> 00:51.710 Now the next top doesn't have to be the final destination of the packet. 00:51.720 --> 01:01.530 It can also be our path to another router that will run the packet forwards each routing hoping the 01:01.530 --> 01:11.310 routing part requires our 48 to do a routing table lookup that will pass the packet along until it reaches 01:11.430 --> 01:23.440 its destination no forty eight does two routing lookups for each session for the first packet that is 01:23.440 --> 01:33.430 sent by the originator and for the first packet that is sent by the responder as it finishes its routing 01:33.430 --> 01:41.110 lookups he writes the routing information in the session table and all other packets that belong to 01:41.110 --> 01:44.740 that session will follow this path. 01:46.120 --> 01:55.690 Now when your foot is tries to match a route to a packet destination it may find some routes to the 01:55.690 --> 01:57.260 same destination. 01:57.370 --> 01:59.650 Which one should he choose. 02:01.200 --> 02:02.550 Well it depends. 02:02.580 --> 02:10.570 It depends on the route attributes the road attributes determine the best road. 02:10.620 --> 02:13.350 All right that's enough for now. 02:13.440 --> 02:15.640 We will look at static crowds. 02:15.690 --> 02:19.380 These are roads that are entered manually. 02:19.500 --> 02:30.540 We will look at dynamic routing which is configured dynamically using dynamic protocols such as OS P.F.. 02:30.540 --> 02:39.240 We will also look at policy rounds which is following its very advanced policy routing mechanism. 02:39.240 --> 02:45.450 We will look at the different routing attributes Internet services routing. 02:45.900 --> 02:46.650 So let's start.