CN Lec2.pdf

IT2050 - COMPUTER NETWORKS Lecture 2 IP Addressing IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Addressing with TCP/IP Address Physical Logical Port Address Address...

IT2050 - COMPUTER NETWORKS Lecture 2 IP Addressing IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Addressing with TCP/IP Address Physical Logical Port Address Address Address MAC Address IP Address Port Address Identify a Computer Identify a Process IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Physical Address Stored in the Network Interface Card (NIC) A hardware setting set by the manufacturer of NIC. Unchangeable Ex :- MAC address For Ethernet, the MAC address is a 48 bit or 12 Hex number Ex : 5A:B3:87:F1:93:7C 5A-B3-87-F1-93-7C MAC address operates in the Data Link Layer (Layer 2) Ethernet Frame CRC/FCS DATA DA SA SOF Preamble IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Logical Address Address scheme depends on the used protocol Widely used protocol is TCP/IP Ex :- IP Address 192.168.16.53 10.39.40.3 Logical address operates at the Network Layer (Layer 3) IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara IP Address Uniquely identifies devices IP Version 4 (IPV4) 32 bit scheme IP Addresses IP Version 6 (IPV6) (IPng) 128 bit scheme IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara IP Version 4 (IPV4) The 32 bits are represented in following manner. Byte 1. Byte 2. Byte 3. Byte 4 ( 1 byte = 8 bits) IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara IP Version 4 (IPV4) cont. IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara IP Version 4 (IPV4) cont. The minimum value of a byte 00000000 = 0 The maximum value of a byte 11111111 = 255 The minimum IP Address 0.0.0.0 The maximum IP Address 255.255.255.255 IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Network ID and Host ID IP Addresses  Network ID + Host ID Class Net ID Host ID A 1 Byte 3 Bytes B 2 Bytes 2 Bytes C 3 Bytes 1 Byte IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara IPv4 Address Classes 10 Rick Graziani [email protected] IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Classes of IP addresses cont. Class D is introduced for Multicasting Class E is reserved IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Classes of IP addresses cont. Class D Addresses A Class D address begins with binary 1110 in the first octet. First octet range 224 to 239. Class D address can be used to represent a group of hosts called a host group, or multicast group. Class E Addresses First octet of an IP address begins with 1111 Class E addresses are reserved for experimental purposes and should not be used for addressing hosts or multicast groups. IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara  Class A byte 1 0 Class B byte 1 1 0 Class C byte 1 1 1 0 Class Minimum Network ID Maximum Networks ID 0 0000000 0 1111111 A 0 127 10 000000.00000000 10 111111.11111111 B 128.0 191.255 C 110 00000.00000000.00000000 110 11111.11111111.11111111 192.0.0 223.255.255 IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara  Class A – 2^7 Class B – 2^14 Class C – 2^21 IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Network Address and Broadcast Address For the Network Address, the Host ID part of the IP Address will be considered as All 0s For the Broadcast Address, the Host ID part of the IP Address will be considered as All 1 Ex : 103.58.35.1 This is a Class A address Net ID is = 103 Host ID is = 58.35.1 Network Address  103.0.0.0 Broadcast Address  103.255.255.255 IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara  198. 8. 0. 1 Class C 1100 0110. 0000 1000. 0000 0000. 0000 0001 Network ID : 3 bytes (24 bits) Host ID : 1 byte (8 bits) Both in Network ID and Host ID all 0s and all 1s are reserved for special purposes. The actual maximum no. of Hosts per Network =28 - 2 = 254 Network Address : 1100 0110. 0000 1000. 0000 0000. 0000 0000 (198.8.0.0) Broadcast Address : 1100 0110. 0000 1000. 0000 0000. 1111 1111 (198.8.0.255) IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Classful Addressing - Subnet Mask Net ID part : All 1’s Host ID part : All 0’s IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Exercise IP Address Class Subnet Actual Network Broadcast Mask No.of Address Address hosts 140.35.45.55 50.60.70.5 201.35.40.201 125.38.55.185 193.201.55.105 127.53.35.10 IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara IP address of a Router A router has many ports. (LAN and WAN Ports) An IP address is assigned to each port. IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Default Gateway IP Address Network Address Gateway IP Address 120.0.0.0 120.0.0.50 152.20.0.0 152.20.0.50 200.53.30.0 200.53.30.50 201.55.30.0 201.55.30.50 138.57.0.0 138.57.0.50 180.50.0.0 180.50.0.50 The IP address of router port which is connected to a particular LAN is called the “Gateway IP Address” of the LAN IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Public IP Addresses A public IP address is any valid address that can be accessed over the Internet The Internet is a Public Computer Network which is spread all over the world. Allocations of IP addresses are controlled by the Internet Assigned Number Authority (IANA) which responsible for the IP address ranges allocation to different countries. CINTEC assigns different range of IP address to different Internet Service Providers (ISPs) The ISPs allocate IP addresses to their customers Sri Lanka Telecom(SLT) provides allocates 8 IP addresses for each 64 kb/s leased line. IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Private IP Addresses A private IP address is address assigned to a device on a private LAN that is accessible only within the LAN. A network which is not connected to Internet can use any IP address range without obtaining any permission It is not advisable to use any IP address since the network may connect to Internet in the future To avoid such problems, IANA has reserved some IP address ranges for private use Class Private Network Address No.of Networks A 10.0.0.0 1 B 172.16.0.0 to 172.31.0.0 16 C 192.168.0.0 to 192.168.255.0 256 IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara IP special addresses Net ID Host ID Remarks Network Address Specific All 0’s None Direct Broadcast Specific All 1’s Destination Address Address Limited Broadcast All 1’s All 1’s Destination Address Address This Host on this All 0’s All 0’s Source Address Network Specific host on this All 0’s Specific Destination Address network Loopback Address 127 Any Destination Address IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Network Address IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Direct Broadcast Address IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Limited Broadcast Address IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara This host on this network IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Specific host on this network IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Loopback address IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Classful Addressing IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Masking Concept IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara AND Operation IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Subnetting – Classless Addressing Suppose you are given a network address 150.100.0.0 /16 for your network. 10010110.01100100.00000000.00000000 You have the computers of Finance, Production and Administration Sections. In order to enhance the efficiency of network you want divide this into three networks. But you cannot get another two network addresses. This requirement can be satisfied from the same network address by using the subnet concept. Now the IP address is divided into three parts. Net ID Subnet ID Host ID IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Classless Addressing cont. The original Net ID bits not changed. Part of Host ID is allocated for “Subnet ID”. Most significant bits allocated as Subnet ID. XXXX XXXX. XXXX XXXX.. XXXX XXXX. XXXX XXXX Net ID Subnet ID Host ID IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Classless Addressing cont. subnets can be written as Subnet 0 10010110.01100100.00000000.00000000 Subnet 1 10010110.01100100.01000000.00000000 Subnet 2 10010110.01100100.10000000.00000000 Subnet 3 10010110.01100100.11000000.00000000 In dotted decimal, it can be written as, Subnet 0 address 150.100.0.0 /18 Subnet 1 address 150.100.64.0 /18 Subnet 2 address 150.100.128.0 /18 Subnet 3 address 150.100.192.0 /18 IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Classless Addressing cont. For the above example the Finance, Production and Administration Sections can be put to three subnets as follows. Consider the hosts in subnet 150.100.64.0 150.100.64.0 The IP addresses can be given as 150.100.64.1 R 150.100.64.2 150.100.128.0 150.100.64.3 150.100.64.4 etc. 150.100.192.0 IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara Classless Addressing cont. In classless addressing the number of bits for network address cannot be decided. Indicated with a “/” symbol. The IP address is written as, 150.100.64.1 /18 150.100.64.2 /18 150.100.64.3 /18 the subnet mask will be, 11111111.11111111.11000000.00000000 255.255.192.0 IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara  Write the possible 12 subnet addresses of 150.72.0.0 / 16 network. 150.72.96.0 / 20 150.72.0.0 / 20 150.72.16.0 / 20 150.72.112.0 / 20 150.72.32.0 / 20 150.72.128.0 / 20 150.72.48.0 / 20 150.72.144.0 / 20 150.72.64.0 / 20 150.72.160.0 / 20 150.72.80.0 / 20 150.72.176.0 / 20 IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara  VLSM Variable Length Sub-netting IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara  An organization is granted the block 130.34.12.64/26. The organization needs 4 subnets. What is the subnet prefix length? Solution We need 4 subnets, which means we need to add two more bits (log2 4 = 2) to the site prefix. The subnet prefix is then /28. 40 TCP/IP Protocol Suite IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara VLSM Variable Length subnet Masking The number of devices are not equal in all the subnets Prefixes vary for separate subnets IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara  Class-full routing – Only allows for one subnet mask for all networks VLSM & Classless routing – The process of subnetting a subnet – More than one subnet mask can be used – More efficient use of IP addresses as compared to classfull IP addressing IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara  An organization is granted a block of addresses with the beginning address 14.24.74.0/24. There are 232−24= 256 addresses in this block. The organization needs to have 11 subnets as shown below: a. 2 subnets, each with 64 addresses. b. 2 subnets, each with 32 addresses. c. 3 subnets, each with 16 addresses. d. 4 subnets, each with 4 addresses. Design the subnets. 44 TCP/IP Protocol Suite IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara TCP/IP Protocol Suite 45 IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara  VLSM Example using /30 subnets 207.21.24.0/24 network subnetted into eight /27 (255.255.255.224) subnets This network has seven /27 subnets with 30 hosts each AND eight /30 subnets with 2 hosts each. /30 subnets are very useful for serial networks. 207.21.24.192/27 subnet, subnetted into eight /30 (255.255.255.252) subnets IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara  207.21.24.192/27 207.21.24. 11000000 /30 Hosts Bcast 2 Hosts 0 207.21.24.192/30 207.21.24. 110 00000 01 10 11.193 &.194 1 207.21.24.196/30 207.21.24. 110 00100 01 10 11.197 &.198 2 207.21.24.200/30 207.21.24. 110 01000 01 10 11.201 &.202 3 207.21.24.204/30 207.21.24. 110 01100 01 10 11.205 &.206 4 207.21.24.208/30 207.21.24. 110 10000 01 10 11.209 &.210 5 207.21.24.212/30 207.21.24. 110 10100 01 10 11.213 &.214 6 207.21.24.216/30 207.21.24. 110 11000 01 10 11.217 &.218 7 207.21.24.220/30 207.21.24. 110 11100 01 10 11.221 &.222 Rick Graziani 47 [email protected] IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara  207.21.24.192/30 207.21.24.192/30 207.21.24.204/30 207.21.24.204/30 207.21.24.216/30 207.21.24.216/30 207.21.24.96/27 207.21.24.128/27 207.21.24.64/27 207.21.24.64/27 207.21.24.208/30 207.21.24.196/30 207.21.24.196/30 207.21.24.200/30 207.21.24.212/30 207.21.24.160/27 207.21.24.224/27 207.21.24.32/27 207.21.24.0/27 207.21.24.160/27 207.21.24.224/27 This network has seven /27 subnets with 30 hosts each AND seven /30 subnets with 2 hosts each (one left over). /30 subnets with 2 hosts per subnet do not waste host addresses on serial networks. IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara VLSM and the Routing Table Routing Table without VLSM RouterX#show ip route Displays one subnet mask for 207.21.24.0/27 is subnetted, 4 subnets all child routes. Classful C 207.21.24.192 is directly connected, Serial0 mask is assumed for the C 207.21.24.196 is directly connected, Serial1 parent route. C 207.21.24.200 is directly connected, Serial2 C 207.21.24.204 is directly connected, FastEthernet0 Each child routes displays its own subnet mask. Classful mask is included for the parent route. Routing Table with VLSM RouterX#show ip route 207.21.24.0/24 is variably subnetted, 4 subnets, 2 masks C 207.21.24.192 /30 is directly connected, Serial0 C 207.21.24.196 /30 is directly connected, Serial1 C 207.21.24.200 /30 is directly connected, Serial2 C 207.21.24.96 /27 is directly connected, FastEthernet0 Parent Route shows classful mask instead of subnet mask of the child routes. Each Child Routes includes its subnet mask. IT 2050| Computer Networks| IP addressing| Hansika Mahaadikara