1 00:00:10,280 --> 00:00:15,830 Everyone that might have that here again in this lecture I'm going to speak about the packet flow in 2 00:00:15,920 --> 00:00:21,650 my critique and that's really an important topic to understand because when you know the packet flow 3 00:00:21,650 --> 00:00:29,540 how it works then it becomes very easy for you to implement the one you want to do any type of firewalling 4 00:00:29,570 --> 00:00:35,120 or Mangga rules or you want also to use the quality of service that all this happens inside the pie. 5 00:00:35,130 --> 00:00:40,880 So it's very important that you understand the backflow and Mike think how it works and everything else 6 00:00:41,030 --> 00:00:41,940 comes very easy. 7 00:00:41,940 --> 00:00:45,920 And that's the reason why the Course name is traffic control OK. 8 00:00:46,160 --> 00:00:48,820 So let's look what we have here. 9 00:00:48,840 --> 00:00:54,890 So that is the packet flow that we have from Mike that if we look at it at first instance we can say 10 00:00:54,920 --> 00:00:56,910 okay that's very complicated What is this. 11 00:00:56,930 --> 00:00:59,310 I cannot understand what does it mean. 12 00:00:59,360 --> 00:01:06,080 And also I was one of you that also at the beginning I was looking at it as like OK Can someone explain 13 00:01:06,080 --> 00:01:07,580 to you how this works. 14 00:01:07,700 --> 00:01:09,260 Because it's very complicated. 15 00:01:09,290 --> 00:01:13,510 I don't understand anything in how the packet is flowing from one box or another. 16 00:01:13,700 --> 00:01:20,510 But when I made it into small pieces and I took the pieces one by one and then I look at that that I 17 00:01:20,510 --> 00:01:23,330 could understand how the flow is happening. 18 00:01:23,330 --> 00:01:29,990 So if you look here this is the backflow that we have here and I'm going to call the each of the boxes 19 00:01:30,000 --> 00:01:31,090 you see here. 20 00:01:31,160 --> 00:01:32,150 I'll call them boxes. 21 00:01:32,150 --> 00:01:32,610 OK. 22 00:01:32,780 --> 00:01:38,460 So you can see that you have over here well the boxes we call it the lock and process. 23 00:01:38,480 --> 00:01:44,500 And on this box over here is where all the process inside the router happens. 24 00:01:44,930 --> 00:01:45,420 OK. 25 00:01:45,590 --> 00:01:47,100 And then you have this box here. 26 00:01:47,240 --> 00:01:49,530 This is the routing box. 27 00:01:49,580 --> 00:01:54,860 This box here is the empty glass box and this box here is the bridging box. 28 00:01:55,000 --> 00:02:00,130 And we are going to take those boxes one by one and we expand them. 29 00:02:00,230 --> 00:02:05,960 Of course I'm not going to do the appeal because in this lecture I'm going to speak only about the routing 30 00:02:06,050 --> 00:02:11,730 and the bridging because that's mostly used on Mike Vick if you want to know more about that. 31 00:02:12,080 --> 00:02:15,960 Then then you have then to see it yourself. 32 00:02:16,010 --> 00:02:20,870 But with my panache about the routing and the regime you'll be very easy for you to understand also 33 00:02:21,050 --> 00:02:23,850 how the puck flow when you use the others. 34 00:02:23,930 --> 00:02:30,710 So if we thought those boxes over here and we make them into one way so we can look here this is how 35 00:02:30,710 --> 00:02:36,730 it looks like you have the local processor box you have the routing box which is Naisi you have the. 36 00:02:36,770 --> 00:02:41,420 They have to bunk five cars and they may switch between the two and less. 37 00:02:41,600 --> 00:02:48,320 And you have the bridging box which is they are two and then here you have what we call the interface 38 00:02:48,380 --> 00:02:49,670 the Constellation. 39 00:02:49,670 --> 00:02:53,270 And here is the out interface encapsulation. 40 00:02:53,270 --> 00:02:56,640 So this really represents what it was here. 41 00:02:56,810 --> 00:03:03,620 So I just made it that simple so you know what is happening on each of the boxes so if we go back here 42 00:03:03,950 --> 00:03:07,710 on the locker process that's where the process of the packet happens inside the mine. 43 00:03:07,790 --> 00:03:10,880 So that is in the lock up process on the resulting layer. 44 00:03:10,880 --> 00:03:18,680 That's where the routing happens when you for example you are sending traffic from your network to another 45 00:03:18,680 --> 00:03:20,080 network as an example. 46 00:03:20,090 --> 00:03:23,420 This is where the happen on the routing layer. 47 00:03:23,420 --> 00:03:29,840 So this is where the decision of the last three happened and Bill is here also in case you are configuring 48 00:03:30,090 --> 00:03:30,480 us. 49 00:03:30,590 --> 00:03:32,690 So in this box all the decision happened. 50 00:03:32,870 --> 00:03:38,180 And if you are having for example a bridge like all your ports inside the bridge and you're sending 51 00:03:38,180 --> 00:03:44,990 from or the number you do not want to port it to do that this is where the decision of the bridging 52 00:03:45,020 --> 00:03:45,680 happened. 53 00:03:45,860 --> 00:03:46,420 OK. 54 00:03:46,430 --> 00:03:52,840 So let's take the pieces one by one and then we'll see how they look at that. 55 00:03:52,850 --> 00:03:59,310 So if we go now to the make it a bit simplified so what I've done here. 56 00:03:59,530 --> 00:04:06,820 So I took out the ambulance S and I think if you go back here to the first picture so you can see here 57 00:04:06,820 --> 00:04:09,010 we have here and there that's traffic. 58 00:04:09,160 --> 00:04:13,320 And and what we have here is ampere us all together to get out. 59 00:04:13,570 --> 00:04:20,350 And then I took the capture nation and here the out the encapsulation and I made it simplified to only 60 00:04:20,350 --> 00:04:22,630 have the routing and the switching. 61 00:04:22,750 --> 00:04:26,530 So we go here and we see this is how it looks like. 62 00:04:26,590 --> 00:04:33,180 So we have the box which is for bridging the two and we have three around thing and that is how it looks. 63 00:04:33,220 --> 00:04:41,060 It's much simpler now because we are going to do some examples about the routing and about the bridging. 64 00:04:41,110 --> 00:04:41,770 OK. 65 00:04:42,070 --> 00:04:46,720 And over here we have the lock up process that's something we have to keep it because again that's where 66 00:04:46,870 --> 00:04:50,210 the process of the packets happen inside the crowd. 67 00:04:50,510 --> 00:04:51,030 OK. 68 00:04:51,100 --> 00:04:56,130 Now we are going to dig into each of those boxes and see how they look like. 69 00:04:56,350 --> 00:04:59,740 If we go first to the routing because the router. 70 00:04:59,820 --> 00:05:01,800 My critique is a router or. 71 00:05:01,950 --> 00:05:02,360 OK. 72 00:05:02,410 --> 00:05:09,340 So we work first on their office so I will take this piece over here the routing and look how close. 73 00:05:09,340 --> 00:05:12,820 So this is the real way that it looks. 74 00:05:12,820 --> 00:05:18,490 So if I take the spottier this one this is the routing. 75 00:05:18,730 --> 00:05:21,350 And this is the box which is here. 76 00:05:21,520 --> 00:05:28,150 And if you look for the main picture you can see this is the routing so here that is the routing. 77 00:05:28,480 --> 00:05:35,380 So you can see that I have taken this picture over here and I have put it here so you can see it's the 78 00:05:35,380 --> 00:05:36,100 same one. 79 00:05:36,340 --> 00:05:37,420 So that is the wrong thing. 80 00:05:37,420 --> 00:05:38,960 So what happened here. 81 00:05:39,160 --> 00:05:46,330 That's when the traffic comes to here that it will say Are you in traffic or you are not. 82 00:05:46,330 --> 00:05:53,440 And I got that if you are an IP traffic means that it's going to another IP that go into this process 83 00:05:53,440 --> 00:05:54,240 over here. 84 00:05:54,550 --> 00:06:00,390 And this process so this box has also a sup process inside of it. 85 00:06:00,610 --> 00:06:01,090 All right. 86 00:06:01,240 --> 00:06:05,290 So this process has a process and if we want to we can look at it here. 87 00:06:06,440 --> 00:06:08,860 So I will open this up process. 88 00:06:08,980 --> 00:06:10,570 So does this do something. 89 00:06:10,570 --> 00:06:18,220 So I took that picture and this house looks likes as a sop process so we can see that the the routing 90 00:06:18,220 --> 00:06:23,720 decision has inside of it subprocess and you can see it has rerouting it has. 91 00:06:23,830 --> 00:06:28,710 I think the person I'd be set policy routing forward and so forth. 92 00:06:28,720 --> 00:06:32,040 So in my case I'm not going to use IP. 93 00:06:32,080 --> 00:06:32,780 SEC. 94 00:06:32,920 --> 00:06:36,370 OK so I'm going to take out the IP stack. 95 00:06:36,520 --> 00:06:41,580 But just to mention that this process also has a sap process inside of it. 96 00:06:41,680 --> 00:06:44,280 And that's what we call the chain. 97 00:06:44,320 --> 00:06:44,940 OK. 98 00:06:44,950 --> 00:06:52,660 So this if we want to see how it looks and then if we go here then we can see that we have taken the 99 00:06:52,720 --> 00:06:54,200 IP out. 100 00:06:54,460 --> 00:06:58,410 So I took out the IP set then the routing decision. 101 00:06:58,450 --> 00:07:02,010 This box will look like this who have pre-roll thing. 102 00:07:02,110 --> 00:07:07,950 You have the forward you have to push out the input output and the routing decision. 103 00:07:08,000 --> 00:07:14,800 Now as I said inside the routing here there is also inside this sub process there is a process called 104 00:07:15,130 --> 00:07:23,950 chain for example pretty routing if we go here to represent this spot in a road routing connection tracking 105 00:07:23,980 --> 00:07:32,610 mangled routing and this nation that that means if we go back to the picture that when the traffic is 106 00:07:32,610 --> 00:07:39,660 coming to the protracting over here then you can look here on the chain and you say OK on the priority 107 00:07:39,680 --> 00:07:49,650 chain Well I want to for example make a for example in Mangu that you know that you can do in Mangere 108 00:07:49,650 --> 00:07:54,740 room inside the rerouting chain and do all possible to make an mine. 109 00:07:55,070 --> 00:07:55,490 OK. 110 00:07:55,530 --> 00:08:02,130 So that's important to understand because then you can see every time that the packet arrive to a chain 111 00:08:02,250 --> 00:08:07,710 then you can do what you can do inside this chain as you can see here inside those chains there are 112 00:08:07,950 --> 00:08:15,180 a lot of information for example the road pre-landing that's where you can make some rules. 113 00:08:15,300 --> 00:08:22,080 Then it's before it arrives to the connection tracking so you can for example first of packets on the 114 00:08:22,080 --> 00:08:23,200 rope without them. 115 00:08:23,400 --> 00:08:29,070 And then the connection tracking isn't responsible for the IP firewall. 116 00:08:29,130 --> 00:08:30,240 As an example. 117 00:08:30,420 --> 00:08:37,260 So that means that before it arrives to the firewall then you can stop some packet on the road rerouting. 118 00:08:37,480 --> 00:08:42,020 OK you can do for example Mango you can do this generation. 119 00:08:42,600 --> 00:08:45,880 And of course we have to check all the other chain as well. 120 00:08:45,960 --> 00:08:48,370 They put the forward to operate at the bus stop. 121 00:08:48,540 --> 00:08:56,160 But something important to mention that you can see that mangle rules are always before the rules and 122 00:08:56,310 --> 00:09:03,440 before the now you can see here we have the mango rule here before the destination. 123 00:09:03,690 --> 00:09:04,740 We can look here. 124 00:09:04,750 --> 00:09:11,620 The Mengal impled inside the chair is before the filter impled which is also in the food chain. 125 00:09:11,620 --> 00:09:17,430 So it's before the firewall and mangled forward as before. 126 00:09:17,430 --> 00:09:25,020 Also the filter on the floor the manga outpolled is before the filter on the output of the mango post-rock 127 00:09:25,020 --> 00:09:29,350 thing is before Denot of on the starting chain. 128 00:09:29,460 --> 00:09:36,720 So you can see that is everywhere and Man-God is important because on the mango You are making some 129 00:09:36,720 --> 00:09:40,430 labeling on the on the connections and on the packet. 130 00:09:40,560 --> 00:09:46,500 And that's something you can use it for the one you want to do filtering as an example or when you want 131 00:09:46,500 --> 00:09:48,580 to do quality of service as well. 132 00:09:48,900 --> 00:09:57,060 So those are the chain that means if we look back here to this graph Let's see if for example the packet 133 00:09:57,060 --> 00:09:59,000 came to the routing. 134 00:09:59,070 --> 00:10:05,910 We didn't do anything and go to the routing decision that it's a four way means just going to another 135 00:10:06,450 --> 00:10:08,060 IP as an example. 136 00:10:08,070 --> 00:10:09,790 So when it comes to the forwarding. 137 00:10:09,810 --> 00:10:13,020 And you say what I want to block the packet forwarding. 138 00:10:13,020 --> 00:10:18,850 Then you can look through the chain of the forwarding and then you can see OK for where they can I block. 139 00:10:19,020 --> 00:10:23,880 Then you can see and you can say yes I can I have a full auto forward here. 140 00:10:23,940 --> 00:10:29,720 Then you can create a rule on the on the forward chain. 141 00:10:29,890 --> 00:10:35,370 Then in this case you can you can block the traffic going forward to somewhere else. 142 00:10:35,370 --> 00:10:41,600 So that's very important to understand these packet flow because it makes your life easier. 143 00:10:41,820 --> 00:10:42,360 OK. 144 00:10:42,540 --> 00:10:44,400 So this is what I wanted to explain. 145 00:10:44,400 --> 00:10:52,860 So if we go back here to do a routing so we see here that we took the routing box and the route in box 146 00:10:52,860 --> 00:10:54,480 looks like this. 147 00:10:54,660 --> 00:11:01,490 And this has a subprocess and this is a process and it has inside of it IP stack. 148 00:11:01,740 --> 00:11:09,690 So what I've done here I have taken how I set to make it look better and then then inside this process 149 00:11:09,720 --> 00:11:17,250 of the routing are also the chain and that's the chain that are available and you know when the packet 150 00:11:17,250 --> 00:11:22,470 arrives to any of those chain then what you can do you can do filtering you can do mangle you can do 151 00:11:22,800 --> 00:11:24,770 now you can do whatever you want. 152 00:11:24,930 --> 00:11:25,380 OK. 153 00:11:25,470 --> 00:11:30,990 And based on what you see here and here are the chain rerouting input for output or something and each 154 00:11:30,990 --> 00:11:33,140 one has a function inside of it. 155 00:11:33,410 --> 00:11:40,020 OK so what I want to do I will use this routing after being shipped to 5 and I'll put it back in the 156 00:11:40,080 --> 00:11:43,840 normal chart that we showed at the beginning. 157 00:11:43,920 --> 00:11:48,780 But before I do that let's move to the bridging because we said we need to see the routing and we need 158 00:11:48,780 --> 00:11:49,740 to see the bridging. 159 00:11:49,830 --> 00:11:57,760 So this is the bridging part and also if you want we can go to the first one so I'm taking now this 160 00:11:57,760 --> 00:12:04,090 one the bridge and park which is this one here so you can see that is how it looks so I took this box 161 00:12:04,780 --> 00:12:06,200 and now it looks like this. 162 00:12:06,210 --> 00:12:10,690 So that is the box the same one but I just took it by itself. 163 00:12:11,380 --> 00:12:17,090 And inside this box also there is a subprocess. 164 00:12:17,380 --> 00:12:19,190 So it is the process of the breeching. 165 00:12:19,210 --> 00:12:19,720 OK. 166 00:12:19,900 --> 00:12:22,610 So as you can see I make it a bit bigger. 167 00:12:23,050 --> 00:12:25,110 So this is the subprocess. 168 00:12:25,130 --> 00:12:28,290 Do you have a bridge destination that you have for print. 169 00:12:28,340 --> 00:12:34,120 We have here the firewall the rerouting which include the bridging decision and so forth. 170 00:12:34,390 --> 00:12:40,390 So to make it simple Also the bridge you have inside the bridge what we call the IP firewall. 171 00:12:40,390 --> 00:12:47,350 That means that if the packet is going inside the bridge so say to Boston in a bridge and it's going 172 00:12:47,350 --> 00:12:51,780 from one for to another four but there it is inside the same bridge. 173 00:12:51,790 --> 00:12:57,910 So the two boats on the side the same bridge what you can do you can make it also firewall inside the 174 00:12:57,910 --> 00:13:00,230 bridge by enabling the IP firewall. 175 00:13:00,610 --> 00:13:06,330 But most of the time we don't need that because we have the firewall on Layer 3 so I don't want to really 176 00:13:06,380 --> 00:13:09,530 to do I'd be FEIBEL inside the bridge itself. 177 00:13:09,610 --> 00:13:15,990 So to make it easy I have decided to take those IP firewall here to remove them. 178 00:13:16,000 --> 00:13:21,360 Those ones that I have only the bridging that's OK to make it simple. 179 00:13:21,460 --> 00:13:23,940 So after I took out the IP firewall. 180 00:13:23,950 --> 00:13:28,600 Now if you want to put the routing and the bridging together that is how it looks. 181 00:13:28,620 --> 00:13:34,470 So this picture is that is the bridging after we took out the IP firewall and did the routing after 182 00:13:34,470 --> 00:13:43,520 we took out the IP SEC and of course this looks as this one this one. 183 00:13:43,520 --> 00:13:49,490 So what I've done I just made the bridging and routing simplified and then I added them here and now 184 00:13:49,550 --> 00:13:51,150 it looks like this. 185 00:13:51,620 --> 00:13:52,170 OK. 186 00:13:52,310 --> 00:14:00,410 So this is the packet flow for the routing and for the bridging again on the routing first we took out 187 00:14:00,410 --> 00:14:03,930 the Ampere us when we looked through the packet flow. 188 00:14:04,010 --> 00:14:11,490 We took out the encapsulation the the operation and then I took each box by itself and made them simplified 189 00:14:11,900 --> 00:14:17,480 from routing I took out the IP stack and we've seen in the routing there are also some processes which 190 00:14:17,480 --> 00:14:21,400 are the chains and then from the bridging I took out the firewall. 191 00:14:21,500 --> 00:14:29,390 And I made it simplified and then I added here and now we have the backflow for the routing and for 192 00:14:29,390 --> 00:14:30,230 the bridging. 193 00:14:30,440 --> 00:14:37,100 So for now what we have is more a simplified way that the though how it looks like. 194 00:14:37,100 --> 00:14:38,650 Now I need to do examples. 195 00:14:38,660 --> 00:14:44,370 I'm going to do five examples for all the drafting and the bridging to show you how fast the package 196 00:14:44,390 --> 00:14:47,370 is flowing when you want to send it on the mike.