IP Addressing Objectives:  Internet Architecture IPv4 Addressing IP

IP Addressing Objectives: Internet Architecture IPv4 Addressing IP address Classes Subnets and subnet mask Subnets design with IP addressing IPv6

Internet Architecture Taibah University Two computers, anywhere in the world, following certain hardware, software, protocol specifications, can communicate, reliably even when not directly connected. LANs are no longer scalable beyond a certain number of stations or geographic separation. 2

Internet Addresses Taibah University IP Address as a 32-Bit Binary Number 3

Decimal Equivalents of 8-Bit Patterns Taibah University 4

Binary and Decimal Conversion Taibah University 5

IP Address Classes Taibah University 6

IP Address Classes Taibah University 7

IP Addresses as Decimal Numbers Taibah University 8

Hosts for Classes of IP Addresses Taibah University Class A (24 bits for hosts) 224 - 2* 16,777,214 maximum hosts Class B (16 bits for hosts) 216 - 2* 65,534 maximum hosts Class C (8 bits for hosts) 28 - 2* 254 maximum hosts * Subtracting the network and broadcast reserved address 9

IPv4 Address Classes Taibah University 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 First octet range 240 to 255. Class E addresses are reserved for experimental purposes and should not be used for addressing hosts or multicast groups. 10

IP Addresses as Decimal Numbers Taibah University 11

Network IDs and Broadcast Addresses Taibah University An IP address such as 176.10.0.0 that has all binary 0s in the host bit positions is reserved for the network address. An IP address such as 176.10.255.255 that has all binary 1s in the host bit positions is reserved for the broadcast address. 12

Private Addresses Taibah University 13

Reserved Address Space Taibah University Network ID Broadcast address Hosts for classes of IP addresses 14

Basics of Subnetting Taibah University Classical IP addressing Subnetworks Subnet mask Boolean operations: AND, OR, and NOT Performing the AND function 15

Subnetworks Taibah University To create a subnet address, a network administrator borrows bits from the original host portion and designates them as the subnet field. 16

Subnetworks Taibah University 17

Subnet Mask Taibah University Determines which part of an IP address is the network field and which part is the host field Follow these steps to determine the subnet mask: – 1. Express the subnetwork IP address in binary form. – 2. Replace the network and subnet portion of the address with all 1s. – 3. Replace the host portion of the address with all 0s. – 4. Convert the binary expression back to dotted-decimal notation. 18

Subnet Mask Taibah University Subnet mask in decimal 255.255.240.0 19

Boolean Operations: AND, OR, and NOT Taibah University AND is like multiplication. OR is like addition. NOT changes 1 to 0, and 0 to 1. 20

Performing the AND Function Taibah University 21

Range of Bits Needed to Create Subnets Taibah University 22

Subnet Addresses Taibah University 23

Creating a Subnet Taibah University Determining subnet mask size Computing subnet mask and IP address Computing hosts per subnetwork Boolean AND operation IP configuration on a network diagram Host and subnet schemes Private addresses 24

Determining Subnet Mask Size Taibah University Class B address with 8 bits borrowed for the subnet 130.5.2.144 (8 bits borrowed for subnetting) routes to subnet 130.5.2.0 rather than just to network 130.5.0.0. 25

Determining Subnet Mask Size Taibah University Class C address 197.15.22.131 with a subnet mask of 255.255.255.224 (3 bits borrowed) 11000101 Network Field 00001111 00010110 100 00011 SN Host Field The address 197.15.22.131 would be on the subnet 197.15.22.128. 26

Subnetting Example with AND Operation Taibah University 27

IP Configuration on a Network Diagram Taibah University The router connects subnetworks and networks. 28

Subnet Example Taibah University Given the Class B address 190.52.0.0 Class B Using /24 subnet. Network Network Network Network Host Subnet Host Host Internet routers still “see” this net as 190.52.0.0 190.52.1.2 190.52.2.2 190.52.3.2 But internal routers think all these addresses are on different networks, called subnetworks 29

Subnet Example Taibah University Network Network Subnet Host Using the 3rd octet, 190.52.0.0 was divided into: 190.52.1.0 190.52.5.0 190.52.9.0 190.52.13.0 190.52.17.0 190.52.2.0 190.52.6.0 190.52.10.0 190.52.14.0 190.52.18.0 190.52.3.0 190.52.7.0 190.52.11.0 190.52.15.0 190.52.19.0 190.52.4.0 190.52.8.0 190.52.12.0 190.52.16.0 and so on . 30

Subnet Example Taibah University Network address 190.52.0.0 with /16 network mask Using Subnets: subnet mask 255.255.255.0 or /24 Network Network Subnet Host 190 190 190 190 190 190 190 52 52 52 52 52 52 52 0 1 2 3 Etc. 254 255 Host Host Host Host Host Host Host Subnet s 255 Subnets 28 - 1 Cannot use last subnet as it contains broadcast 31

Subnet Example Taibah University Subnet 0 (all 0’s subnet) issue: The address of the subnet, 190.52.0.0/24 is the same address as the major network, 190.52.0.0/16. Network Network 190 190 190 190 52 52 52 52 Subnet Host 0 1 Etc. 254 Host Host Host Host Subnet s 255 Subnets 28 - 1 190 52 255 Host Last subnet (all 1’s subnet) issue: The broadcast address for the subnet, 190.52.255.255 is the same as the broadcast address as the major network, 190.52.255.255. 32

Host Subnet Schemes Taibah University The number of lost IP addresses with a Class C network depends on the number of bits borrowed for subnetting. 33

IP addressing crisis Taibah University Address Depletion Internet Routing Table Explosion 34

IPv4 Addressing Taibah University Subnet Mask One solution to the IP address shortage was thought to be the subnet mask. Formalized in 1985 (RFC 950), the subnet mask breaks a single class A, B or C network in to smaller pieces. 35

Short Term Solutions: IPv4 Enhancements Taibah University CIDR (Classless Inter-Domain Routing) – RFCs 1517, 1518, 1519, 1520 VLSM (Variable Length Subnet Mask) – RFC 1009 Private Addressing - RFC 1918 NAT/PAT (Network Address Translation / Port Address Translation) – RFC 36

IPv4 versus IPv6 Taibah University IP version 6 (IPv6) has been defined and developed. IPv6 uses 128 bits rather than the 32 bits currently used in IPv4. IPv6 uses hexadecimal numbers to represent the 128 bits. IPv4 37

Long Term Solution: IPv6 (coming) Taibah University IPv6, or IPng (IP – the Next Generation) uses a 128-bit address space, yielding 340,282,366,920,938,463,463,374,607,431,768,211,456 possible addresses. IPv6 has been slow to arrive IPv4 revitalized by new features, making IPv6 a luxury, and not a desperately needed fix IPv6 requires new software; IT staffs must be retrained IPv6 will most likely coexist with IPv4 for years to come. Some experts believe IPv4 will remain for more than 10 years. 38