0 1 00:00:00,480 --> 00:00:05,440 ... 1 2 00:00:05,450 --> 00:00:11,670 ... 2 3 00:00:14,940 --> 00:00:23,490 An Internet Protocol address (IP address) is a numerical label assigned to each device connected to 3 4 00:00:23,620 --> 00:00:32,280 the computer network that uses the Internet protocol for communication an IP address serves two principal 4 5 00:00:32,280 --> 00:00:43,770 functions: host or network interface identification and location addressing. Internet Protocol version 4 (IPv4) defines an IP address as a  5 6 00:00:43,800 --> 00:00:46,570 32-bit number.[ 6 7 00:00:46,610 --> 00:00:55,550 However, because of the growth of the Internet and the depletion of available IPv4 addresses, 7 8 00:00:55,740 --> 00:01:05,580 a new version of IP (IPv6), using 128 bits for the IP address. 8 9 00:01:06,660 --> 00:01:22,770 When the PDU named segment reaches the Network Layer, this layer adds the IPv4 or IPv6 headers 9 10 00:01:22,770 --> 00:01:30,780 to the segment and PDU name is converted to «Packet» in network layer. 10 11 00:01:31,150 --> 00:01:35,060 And let's take a look to IP version 4 header now. 11 12 00:01:35,220 --> 00:01:43,080 And as you can see that there are lots of fields in IP v4 version header and they are 12 13 00:01:43,120 --> 00:01:45,220 version field, 13 14 00:01:45,350 --> 00:01:55,040 They are type of service fields, header length field, total length field , fragment offset, protocol, TTL 14 15 00:01:55,330 --> 00:02:01,690 header checksum, source and destination IP addresses and IP option. 15 16 00:02:01,900 --> 00:02:11,490 Please keep in mind that there are lots of fields in here as you can see. 16 17 00:02:11,610 --> 00:02:13,740 lets take a look to ipv4 limitations. 17 18 00:02:13,740 --> 00:02:20,280 As we talked in our first slide of our course, almost 50 billion devices will be connected to internet 18 19 00:02:20,370 --> 00:02:22,170 by 2020. 19 20 00:02:22,190 --> 00:02:25,540 but however Available IPv4 addresses 20 21 00:02:25,590 --> 00:02:32,870 are decreasing. In spite of IPv4 is still the most common used protocol, 21 22 00:02:32,910 --> 00:02:41,460 it seems like our next step will be IPv6 which can provide a broad ip address range. 22 23 00:02:42,210 --> 00:02:51,930 IPv6 provides a huge IP address range and more secure environment. With IPv4, we will not 23 24 00:02:51,930 --> 00:02:59,460 Network Address Translation operation which converts 24 25 00:02:59,460 --> 00:03:05,630 private ip addresses into public ip addresses. 25 26 00:03:05,870 --> 00:03:12,540 And let's take a look to the differences between IPV 4 and IP version 6. 26 27 00:03:12,580 --> 00:03:23,180 The first difference is address size. IPV 4 is thirty eight bit number while IP version 6 is one hundred 27 28 00:03:23,240 --> 00:03:26,180 and twenty eight bit number. 28 29 00:03:26,180 --> 00:03:33,190 The second is address format. IPV 4 is shown in decimal notation. 29 30 00:03:33,200 --> 00:03:43,160 As you can see there are dots between the decimal numbers while IP version 6 is shown in hexadecimal 30 31 00:03:43,460 --> 00:03:49,070 notation and there is a difference in the prefix notation as well. 31 32 00:03:49,190 --> 00:03:57,800 And the biggest difference between these guys is really the number of the addresses that they are supporting. 32 33 00:03:57,830 --> 00:04:08,360 As you can see there ipv4 is supporting this and Ip version 6 is supporting a really huge 33 34 00:04:08,360 --> 00:04:12,110 number of IP addresses. 34 35 00:04:12,110 --> 00:04:13,000 Let's take a look. 35 36 00:04:13,000 --> 00:04:15,240 The IP version 6 header now. 36 37 00:04:15,250 --> 00:04:26,470 Ipv6 header is pretty straight forward as you can see. on the screen there are 14 fields 37 38 00:04:26,530 --> 00:04:34,090 in the IP version for header as you can see version I H-L type of service total length and et 38 39 00:04:34,510 --> 00:04:43,540 but there are just 8 fields in ipv6 header and they are version, traffic class 39 40 00:04:43,540 --> 00:04:53,690 flow label, payload length….. 40 41 00:04:53,700 --> 00:04:55,190 Let's take a look to the routers. 41 42 00:04:55,200 --> 00:05:06,300 Now. A router is a Layer 3 network gateway device, meaning that it connects two or more networks and 42 43 00:05:06,420 --> 00:05:12,100 that the router operates at the network layer of the OSI model. 43 44 00:05:12,300 --> 00:05:19,830 The main function of router is «ip routing» using the routing table entries. 44 45 00:05:19,920 --> 00:05:26,620 If you remember from our previous slides, on the switches 45 46 00:05:29,730 --> 00:05:37,320 there was a MACaddress table and switches we were making the switching by using the MAC address entries on 46 47 00:05:37,320 --> 00:05:38,990 the Mac table. 47 48 00:05:39,150 --> 00:05:44,060 But what rotuers are doing is, this is a router 48 49 00:05:44,190 --> 00:05:55,310 this guy is keeping a routing table this time routing table which consists of IP Address entries, 49 50 00:05:55,970 --> 00:06:04,660 and routers are making IP routing by using the IP address is kept in the routing table. 50 51 00:06:05,770 --> 00:06:14,350 And here is backplane of a router as you can see there are some equipments in here, like on off switch 51 52 00:06:15,130 --> 00:06:24,580 , like the input power connection, like the gigabit ethernet ports like usb ports and something like that 52 53 00:06:24,580 --> 00:06:30,810 if you want to check routers' physical view, deeply there is a great application on Google 53 54 00:06:30,900 --> 00:06:39,130 Play store and you can simply go the Google Play store and type Cisco 3D interactive 54 55 00:06:39,190 --> 00:06:46,600 catalog and you can check the physical view of the routers deeply there. 55 56 00:06:46,870 --> 00:06:47,770 .. 56 57 00:06:48,190 --> 00:06:50,980 Let's take a look to the router memory now. 57 58 00:06:51,100 --> 00:06:52,600 In router memory. 58 59 00:06:52,600 --> 00:06:55,900 We have four types of memory. 59 60 00:06:55,930 --> 00:07:00,180 The first one is RAM 60 61 00:07:00,190 --> 00:07:02,560 The second is ROM. 61 62 00:07:02,770 --> 00:07:08,510 And the other ones are NVRAM and the flash. In RAM 62 63 00:07:08,800 --> 00:07:18,040 We are storing the running I O S, which is the operating system of the router and the running configuration 63 64 00:07:18,160 --> 00:07:24,060 routing and ARP tables and packet buffers. in the ROM 64 65 00:07:24,310 --> 00:07:34,560 We are storing the boot up instructions and limited Ios, in the NVRAM we are storing the sturtup config. 65 66 00:07:34,750 --> 00:07:41,320 And in the flash we are storing the IOS itself and the other system files. 66 67 00:07:41,470 --> 00:07:46,020 And please keep in mind that just ram is valotile. 67 68 00:07:46,450 --> 00:07:50,150 So how a router boots up? 68 69 00:07:50,300 --> 00:07:52,660 Let's take a look at this. 69 70 00:07:52,690 --> 00:08:00,290 The first thing when router is booting up is POST: power on self tests. on this step. 70 71 00:08:00,330 --> 00:08:05,120 The hardware is being checked. 71 72 00:08:05,330 --> 00:08:15,910 Then ROM loads the bootstrap program and searches for the IOS which is the operating system of 72 73 00:08:16,510 --> 00:08:27,580 the router . than iOS is being loaded from the flash and the startup configuration is loaded from the 73 74 00:08:27,670 --> 00:08:36,900 NVRAM and in the last step, boot process is completed as everything is loaded into the ram. 74 75 00:08:37,170 --> 00:08:39,500 Let's take a look through the routing process. 75 76 00:08:39,510 --> 00:08:52,320 If source and destination have same network IDs, source sends the packet directly to the destination 76 77 00:08:52,370 --> 00:08:57,860 That's a really important thing that you should keep on your mind. 77 78 00:08:58,040 --> 00:09:01,370 But what is a Network ID? 78 79 00:09:01,560 --> 00:09:10,280 (network ID) is a portion of the IP address that is used to identify individuals or devices on a network 79 80 00:09:10,280 --> 00:09:15,530 such as a local area network or the Internet. On our later section 80 81 00:09:15,710 --> 00:09:21,180 We'll see how we can calculate the network ID value as well. 81 82 00:09:21,410 --> 00:09:30,020 But If source and destination have different network IDs from each other, source sends the packet to 82 83 00:09:30,380 --> 00:09:38,780 A default gateway is the node in a computer network using the Internet 83 84 00:09:38,780 --> 00:09:46,740 Protocol Suite that serves as the forwarding host (router) to other networks when no other route specification 84 85 00:09:46,750 --> 00:09:50,720 matches the destination IP address of a packet. 85 86 00:09:50,750 --> 00:10:04,500 For example in here PC one wants to communicate with the PC 4, they have different network IDs the 86 87 00:10:04,720 --> 00:10:07,930 network id of PC one is .1 87 88 00:10:10,460 --> 00:10:21,360 network ID of pc 4 is .20, 20 I'm going to show you how I calculate these numbers 88 89 00:10:21,370 --> 00:10:26,800 later sections then because they have different network IDs, 89 90 00:10:26,810 --> 00:10:36,490 If PC one wants to communicate with the PC 4 , this guy directly throws the packet to the default 90 91 00:10:36,490 --> 00:10:45,980 gateway which is the internal interface IP address of this router on the middle. 91 92 00:10:46,410 --> 00:10:57,870 But if PC one wants to communicate with the PC two and because they have the same network IDs, the packet 92 93 00:10:57,870 --> 00:11:10,270 the packet is not forwarded to default gateway and that is directly forwarded to the PC two. 93 94 00:11:10,290 --> 00:11:15,630 So let's take a look how we can configure an IP address for switches. 94 95 00:11:15,630 --> 00:11:27,060 Now, if we want to communicate the default gateway on switch the command we're using is IP default-gateway 95 96 00:11:27,180 --> 00:11:34,140 and the IP address of the router's internal interface. 96 97 00:11:34,360 --> 00:11:42,210 And if you want to configure a default gateway for hosts, for example for this PC, if I want 97 98 00:11:42,210 --> 00:11:51,480 to configure the default gateway, on the Internet Options There is a field showing us the default gateway 98 99 00:11:51,510 --> 00:12:02,630 I can simply fill this here with the IP address of the default gw configure my host. 99 100 00:12:02,630 --> 00:12:11,330 So the next thing we are going to focus on is the routing table. in computer networking routing table 100 101 00:12:11,500 --> 00:12:21,250 is a data table stored in a router or a networked computer that lists the best paths to particular network 101 102 00:12:21,340 --> 00:12:22,320 destinations. 102 103 00:12:22,480 --> 00:12:28,290 and in some cases, metrics (distances) associated with those routes 103 104 00:12:28,540 --> 00:12:33,890 The key term in here is the best path. 104 105 00:12:33,910 --> 00:12:45,600 For example let's say that you want to go from London to Manchester. what you will do is you open the Google 105 106 00:12:48,110 --> 00:12:52,300 Maps perhaps. 106 107 00:12:52,560 --> 00:12:57,230 And London is here and Manchester is in here let's say. 107 108 00:12:57,530 --> 00:13:05,870 And when you open the Google Maps you use the London to the From field and you enter the Manchester 108 109 00:13:05,870 --> 00:13:07,860 to the destination field. 109 110 00:13:08,000 --> 00:13:14,160 Then Google Maps shows you a few 110 111 00:13:14,270 --> 00:13:19,240 Alternate paths how to how to get from London to Manchester. 111 112 00:13:19,330 --> 00:13:22,810 But offers you one best path. 112 113 00:13:22,840 --> 00:13:33,480 That's the fastest one. 113 114 00:13:33,480 --> 00:13:43,460 So routing table is something like that too in the routing table You will always have the best path for the particular . 114 115 00:13:43,550 --> 00:13:44,510 destination. 115 116 00:13:44,540 --> 00:13:53,060 In here we're seeing an example of the routing table and we need to type "show ip route" simply to display 116 117 00:13:53,060 --> 00:13:54,820 the routing table in here. 117 118 00:13:54,830 --> 00:14:03,740 And as you can see in here for example that's a routing table entry which shows us the how we can reach 118 119 00:14:03,740 --> 00:14:09,130 the 0.1 network , via1.6. 119 120 00:14:09,140 --> 00:14:12,730 It's saying us then that's the best path. 120 121 00:14:12,770 --> 00:14:23,740 And in here also we have another best path. 121 122 00:14:23,740 --> 00:14:31,100 We have also routing tables on our PCs.And to see our PCs routing table, we can type "route print" on our command window. 122 123 00:14:31,630 --> 00:14:40,620 So as I told you if I want to check the router's routing table, I'm typing "show ip route" command and 123 124 00:14:40,680 --> 00:14:47,080 I'm seeing the best paths for the particular destinations. 124 125 00:14:48,610 --> 00:14:53,020 So how I'm going to examine the routing table entries? 125 126 00:14:53,250 --> 00:15:02,710 So in a routing table entry we have some text characters and some numbers as 126 127 00:15:02,710 --> 00:15:10,540 you can see the first character is you're seeing on the routing table entry identifies how the network 127 128 00:15:10,540 --> 00:15:12,880 was learned by the router. 128 129 00:15:12,910 --> 00:15:23,770 For example if this route was learned by statically or learned by a dynamic routing protocol such as maybe 129 130 00:15:23,800 --> 00:15:30,190 EIGRP, OSPF or something like that. 130 131 00:15:30,310 --> 00:15:35,170 The second field identifies destination to the network. 131 132 00:15:35,170 --> 00:15:43,240 Then this field identifies the administrative distance which is the thrustworthiness 132 133 00:15:43,450 --> 00:15:52,240 of the route source . then this field identifies the metric to reach to the remote network and this 133 134 00:15:52,270 --> 00:15:57,820 field identifies the next hop IP address to reach to the remote network. 134 135 00:15:57,850 --> 00:16:06,150 And this field identifies the amount of elapsed time since the network was discovered and here identifies 135 136 00:16:06,160 --> 00:16:11,530 the outgoing interface on the router to reach the destination network. 136 137 00:16:13,170 --> 00:16:21,810 So let's take a look to router packet forwarding now. Routers 137 138 00:16:21,810 --> 00:16:31,020 automatically know the directly connect to networks guys and remote networks must be learned by static routing 138 139 00:16:31,080 --> 00:16:42,380 or dynamic routing protocols.For example if router one wants to communicate with router 2 what I'm gonna do is I'm going to go 139 140 00:16:42,750 --> 00:16:53,630 to router zero and say this guy that hey dude if you want to communicate with this network for example 140 141 00:16:53,930 --> 00:17:04,010 because this guy knows the directly connected interfaces automatically and this guy does not know anything 141 142 00:17:04,070 --> 00:17:10,830 about in here, in here and in here and in here also. 142 143 00:17:11,120 --> 00:17:17,310 So what I'm going to do is I'm going to go to this guy and I'm going to configure something saying that 143 144 00:17:17,720 --> 00:17:19,150 hey router zero. 144 145 00:17:19,370 --> 00:17:27,020 if you want to communicate with the network 2.0 send your packet to for example here 145 146 00:17:27,380 --> 00:17:33,420 Or if you are to communicate with 3.0 send your packet to here. 146 147 00:17:33,680 --> 00:17:42,710 I can manually configure this or use the dynamic routing protocol saying that if you want to go the 147 148 00:17:42,710 --> 00:17:52,660 here use the EIGRP protocol, if you want to go here use the OSPF protocol or something like that. 148 149 00:17:52,820 --> 00:17:58,760 I'm going to show you in much deeper on our later sections. 149 150 00:17:58,760 --> 00:18:00,230 Again. 150 151 00:18:00,430 --> 00:18:08,350 So let's take a look at the basic router configuration now. in a basic router configuration we can simply 151 152 00:18:08,380 --> 00:18:11,950 configure hostname for example. 152 153 00:18:12,070 --> 00:18:15,670 So let's say that we have a router named 153 154 00:18:15,670 --> 00:18:21,090 My router, in the config mode. 154 155 00:18:21,370 --> 00:18:31,840 I need to type host name command and I need to give a host name to our device and as soon as I type 155 156 00:18:31,840 --> 00:18:39,590 the enter as you can see the host name changed to r0 156 157 00:18:40,000 --> 00:18:49,360 And if I want to configure the interface, I need to go to the interface mode by typing interface and 157 158 00:18:49,360 --> 00:18:53,800 the name of the interface which is fa 0/1 for this one. 158 159 00:18:54,160 --> 00:19:05,040 And I am typing IP address and the IP address of the interface and the subnet mask of the interface. 159 160 00:19:05,050 --> 00:19:13,720 All right guys if you could not understand what I'm telling about in here don't worry we are going 160 161 00:19:13,720 --> 00:19:17,990 to make separate a wonderful packet tracer 161 162 00:19:18,010 --> 00:19:21,780 Lab examples and you'll get 162 163 00:19:21,790 --> 00:19:24,690 All of these concepts easily 163 164 00:19:24,730 --> 00:19:25,770 Trust me. 164 165 00:19:26,050 --> 00:19:30,910 So to verify the interface configuration the command I'm using. 165 166 00:19:30,910 --> 00:19:40,930 This time is show IP interface brief and I can check the IP addresses attached to each interface 166 167 00:19:41,080 --> 00:19:43,250 by using this command.