Network layer addressing used for Internet Protocol

IP Addresses

1. Mr. Vipul H. Kondekar ([email protected]) Assistant Professor, Electronics & Telecommunication Engineering Walchand Institute of Technology, Solapur (www.witsolapur.org) Network Layer: IP Addressing-Part I Walchand Institute of Technology, Solapur 1

2. At the end of this session, students will be able to Identify the valid IPv4 Address. Classify the given IP address. Walchand Institute of Technology, Solapur 2 Learning Outcomes

3. Contents Introduction Dotted Decimal form Representation of IP Address Classful IP Addressing Network ID and Host ID representation Address blocks and Addresses per block for each class. Walchand Institute of Technology, Solapur 3

4. Walchand Institute of Technology, Solapur 4 Introduction: The identifier used in the IP layer in TCP/IP suite to identify each device connected to the Internet is called the Internet address or IP address. An IP address is a 32-bit address that uniquely and universally defines the connection of a host or a router to the Internet. IP addresses are unique. They are unique in the sense that each address defines one, and only one, connection to the Internet. Two devices on the Internet can never have the same address.

5. Walchand Institute of Technology, Solapur 5 Dotted decimal form of IP Address An IP address is a 32-bit address . The IP addresses are unique . The address space of IPv4 is 2 32 or 4,294,967,296.

6. Walchand Institute of Technology, Solapur 6 Dotted decimal form of IP Address IP addresses are written in a so-called dotted decimal notation Each byte is identified by a decimal number in the range [0..255]: Example: 10001111 10000000 10001001 10010000 1 st Byte = 128 2 nd Byte = 143 3 rd Byte = 137 4 th Byte = 144 128.143.137.144

7. Walchand Institute of Technology, Solapur 7 Find the error, if any, in the following IP addresses: a. 111.56.045.78 b. 221.34.7.8.20 c. 75.45.301.14 d. 11100010.23.14.67 Solution a. There are no leading zeroes in dotted-decimal notation (045). b. We may not have more than four numbers in an IP address. c. In dotted-decimal notation, each number is less than or equal to 255; 301 is outside this range. d. A mixture of binary notation and dotted-decimal notation is not allowed. Check your understanding?

8. Walchand Institute of Technology, Solapur 8 CLASSFUL ADDRESSING Figure 1 Classes in IP Address Figure 2 Flowchart for Identifying the classs based on bit values Table 1 Percentage of classwise Addresses

9. Walchand Institute of Technology, Solapur 9 Find the class of each address: a. 227.12.14.87 b.193.14.56.22 c.14.23.120.8 d. 252.5.15.111 e.134.11.78.56 Solution a. The first byte is 227 (between 224 and 239); the class is D. b. The first byte is 193 (between 192 and 223); the class is C . c. The first byte is 14 (between 0 and 127); the class is A. d. The first byte is 252 (between 240 and 255); the class is E. e. The first byte is 134 (between 128 and 191); the class is B. Figure 3 Classes in IP Address based on decimal value of first byte

10. Walchand Institute of Technology, Solapur 10 Figure 4 Netid and hostid The network address is the beginning address of each block. It can be found by applying the default mask to any of the addresses in the block (including itself).

11. Walchand Institute of Technology, Solapur 11 Concept of Masking Table 1 Default masks

12. Walchand Institute of Technology, Solapur 12 A network with two levels of hierarchy (not subnetted)

13. Walchand Institute of Technology, Solapur 13 A network with three levels of hierarchy (subnetted)

14. Walchand Institute of Technology, Solapur 14 Subnetting and Supernetting IP addresses are designed with two levels of hierarchy. Figure 2 Hierarchy concept in a telephone number

15. Walchand Institute of Technology, Solapur 15 Advantages of subnetting With subnetting, IP addresses use a 3-layer hierarchy: Network Subnet Host Improves efficiency of IP addresses by not consuming an entire address space for each physical network. Reduces router complexity. Since external routers do not know about subnetting, the complexity of routing tables at external routers is reduced.

16. Walchand Institute of Technology, Solapur 16 Addresses in a network with and without subnetting

17. Walchand Institute of Technology, Solapur 17 Default mask and subnet mask

18. Walchand Institute of Technology, Solapur 18 Comparison of a default mask and a subnet mask

19. Walchand Institute of Technology, Solapur 19 What is the subnetwork address if the destination address is 200.45.34.56 and the subnet mask is 255.255.240.0? Solution We apply the AND operation on the address and the subnet mask. Address ➡ 11001000 00101101 00100010 00111000 Subnet Mask ➡ 11111111 11111111 11110000 00000000 Subnetwork Address ➡ 11001000 00101101 00100000 00000000.

20. Walchand Institute of Technology, Solapur 20 Subnetting Vs Supernetting: In subnetting, we need the first address of the subnet and the subnet mask to define the range of addresses. n sub =n+log 2 S ;n sub =Length of subnet ID,n= Length of net_id,S=No. of subnets In supernetting, we need the first address of the supernet and the supernet mask to define the range of addresses . n super =n-log 2 C n super =Length of supernet ID,n= Length of net_id,C=No. of Blocks forming Supernet

21. Walchand Institute of Technology, Solapur 21 Supernetting Example: Company XYZ needs to address 400 hosts. Its ISP gives them two contiguous Class C addresses: 207.21.54.0/24 207.21.55.0/24 Company XYZ can use a prefix of 207.21.54.0 /23 to supernet these two contiguous networks. (Yielding 510 hosts) 207.21.54.0 /23 207.21.54.0/24 207.21.55.0/24

22. Walchand Institute of Technology, Solapur 22 A supernetwork

23. Walchand Institute of Technology, Solapur 23 Comparison of subnet, default, and supernet masks

24. References Walchand Institute of Technology, Solapur 24 Data communication- B.A. Forouzan 4th Edition Tata Mc Graw hill Publication. TCP/IP protocol suit- B.A. Forouzan 4th Edition Tata Mc Graw hill Publication. Computer Networking, J. Kurose & K. Ross Computer networks- Andrew S.Tanenbaum Internetworking TCP/IP Principal, Protocol and Architecture -Douglas Comer- Addision -Wesley TCP/IP Illustrated, The Protocols – W. Richard Slevens , G.Gabrani –PE pub. Data and computer communication – William Stallings. - PE pub.

25. Walchand Institute of Technology, Solapur 25 Thanks!!