1. Network Layer (part2)6-1 INT-201: Computer Network and Communication System อ. ดร. ภัทร ลีลาพฤทธิ์ Dr. Pattara Leelaprute Computer Engineering Department Kasetsart University pattara.l@ku.ac.th http://www.cpe.ku.ac.th/~pattara/int201 Computer Networking: A Top Down Approach, 4 th edition. Jim Kurose, Keith Ross Addison-Wesley, July 2007. Special Module: IP address

2. Network Layer (part2)6-2 Internet Address

3. Network Layer (part2)6-3 Internet Classes Classfull Addressing

4. Network Layer (part2)6-4 IP Address Class

5. Network Layer (part2)6-5 No. of Network / Host

6. Network Layer (part2)6-6 IP address in decimal notation 2 7 2 6 2 5 2 4 2 3 2 2 2 1 2 0 1 0 0 1 1 1 1 0 xxxx x xxx 158.108.2.61 10011110 01101100 00000010 00111101 128 + 16 + 8 + 4 + 2 + = 158

7. Network Layer (part2)6-7 IP address practice 10011110 01101100 00100000 00010010 158.108.32.18 00001100 00011001 00000001 00010111 12.25.1.23 11001001 01111101 10001001 11010101 201.125.137.213 #1 #2 #3

8. Network Layer (part2)6-8 IP address in decimal notation 158.108.2.61 10011110 01101100 00000010 00111101 www.ku.ac.th

9. Network Layer (part2)6-9 Class ranges of Internet Address

10. Network Layer (part2)6-10 IP Address Class A 50% B 25% C 12.5% D E

11. Network Layer (part2)6-11 IP Addressing: introduction r IP address: 32-bit identifier for host, router interface r interface: connection between host/router and physical link m router’s typically have multiple interfaces m host typically has one interface m IP addresses associated with each interface 223.1.1.1 223.1.1.2 223.1.1.3 223.1.1.4 223.1.2.9 223.1.2.2 223.1.2.1 223.1.3.2 223.1.3.1 223.1.3.27 223.1.1.1 = 11011111 00000001 00000001 00000001 223 111

12. Network Layer (part2)6-12 Subnets r IP address: m subnet part (high order bits) m host part (low order bits) r What’s a subnet ? m device interfaces with same subnet part of IP address m can physically reach each other without intervening router 223.1.1.1 223.1.1.2 223.1.1.3 223.1.1.4 223.1.2.9 223.1.2.2 223.1.2.1 223.1.3.2 223.1.3.1 223.1.3.27 network consisting of 3 subnets subnet

13. Network Layer (part2)6-13 Subnets 223.1.1.0/24 223.1.2.0/24 223.1.3.0/24 Recipe r To determine the subnets, detach each interface from its host or router, creating islands of isolated networks. Each isolated network is called a subnet. Subnet mask: /24

14. Network Layer (part2)6-14 IP addressing: CIDR CIDR: Classless InterDomain Routing m subnet portion of address of arbitrary length m address format: a.b.c.d/x, where x is # bits in subnet portion of address 11001000 00010111 00010000 00000000 subnet part host part 200.23.16.0/23