2. IP Addresses Mark Woodhouse and Arthur Manning

3. IP Addressing Used packets created in Layer 3 of the Open Systems Interconnection (OSI) Model Hierarchical addressing scheme Example: Structure of this course

4. Course Structure CCAI Semester 1Semester 2Layer 3Layer 4IP AddressesSubnetting. IP Addresses. Semester 1. Layer 3CCAI

5. IP Address Structure Four binary octets (bytes) in dotted- decimal format Example: 208. 142. 79. 225 8 bits

6. IP Address Parts 130. 142. 79. 225 Network PartHost Part Balance between Network and Host parts of the IP address varies, based on the “Class” of the IP Address

7. IP Address Classes Class “A” addresses –1 st Octet has a decimal value between 1 and 126 (first binary digit is 0) –Allows for a maximum of ~16 million hosts 108. 142. 79. 225 NetworkHost

8. IP Address Classes Class “B” addresses –1 st Octet has a decimal value between 128 and 191 (first 2 binary digits are 10) –Allows for a maximum of ~65 thousand hosts 128. 142. 79. 225 Network Host

9. IP Address Classes Class “C” addresses –1 st Octet has a decimal value between 192 and 223 (first 3 binary digits are 110) –Allows for a maximum of 254 hosts 208. 142. 79. 225 NetworkHost

10. IP Address Classes Class “D” and “E” addresses –1 st Octet has a decimal value above 223 (first 3 binary digits are 111) –Used for special purposes, not generally available

11. Two Special IP Addresses Network Address: all host bits set to zero 208. 142. 79. 0 NetworkHost

12. Two Special IP Addresses Broadcast Address: all host bits set to one 208. 142. 79. 255 NetworkHost Broadcast packets are forwarded to all hosts on the network!

13. IP Address Classes - Exercise Tell me which class the following addresses belong to: 201. 181. 7. 42 128. 17. 47. 146 3. 1. 1. 2 184. 11. 72. 55 193. 4. 9. 9 Class C Class B Class A Class B Class C

14. Subnets Mark Woodhouse and Arthur Manning

15. What is Subnetting? Borrowing 2 or more bits from the HOST portion of the IP address to extend the NETWORK portion. Divides your allotted IP addresses into separate, discrete networks Final host part of the IP address must contain at least 2 bits

16. Benefits of Subnetting Limits the extent of Broadcast Domains –Instead of going to all IP addresses on the network, broadcasts are forwarded only to those machines on the same subnet Better organization of IP addresses within the enterprise Different media might be used for different LAN segments

17. Subnet Mask Indicates what portion of the IP address represents the network 10001100.10110011.11110000.11001000 11111111.11111111.00000000.00000000 10001100.10110011.00000000.00000000 140.179.240.200 Class B address Class B Net Mask Network Part 140.179

18. Default Subnet Masks Class A Subnet Mask –255. 0. 0. 0 Class B Subnet Mask –255. 255. 0. 0 Class C Subnet Mask –255. 255. 255. 0

19. Borrowing Host Bits to Subdivide the Network Space At least 2 bits must be borrowed from the host part of the IP address At least 2 bits must be left for the Host part of the IP address

20. Example Class B Subnet Mask 11111111.11111111.11100000.00000000 255. 224. 0 Network PartHost Part 11111111.11111111.00000000.00000000 255. 0. 0 Network PartHost Part Three bits borrowed from Host Part to extend the Network Part of the address

21. Example Class B Subnet 000 001 010 011 100 101 110 111 Network Address – Can’t be Used 001 – Useable Subnet Address 010 – Useable Subnet Address 011 – Useable Subnet Address 100 – Useable Subnet Address 101 – Useable Subnet Address 110 – Useable Subnet Address Broadcast Address – Can’t be Used 000 001 010 011 100 101 110 111 Network Address – Can’t be Used 001 – Useable Subnet Address 010 – Useable Subnet Address 011 – Useable Subnet Address 100 – Useable Subnet Address 101 – Useable Subnet Address 110 – Useable Subnet Address Broadcast Address – Can’t be Used Possible Networks

22. Host Addresses on the 011 Subnet 01100000.00000000 01100000.00000001 01100000.00000010. 01111111.11111101 01111111.11111110 01111111.11111111 Network Address Useable Address. Useable Address Broadcast Address (32 x 256)-2 = 8190 Total Useable Hosts on the 011 Subnet SubnetHost