Binary Concepts By: Nathan Miller

What is Binary? The binary numbering system is a method of storing ordinary numbers such as 56 or 250 as patterns of 1’s and 0’s. Computers can easily manipulate these binary patterns by treating 1 as “on” and “0” as off. Binary numbers are much easier and faster to work with because the computer does not need to learn large addition or multiplication tables.

Counting in Decimal The decimal numbering system is a base 10 numbering system. Decimal employs the digits 0-9. When counting past 9 an additional column is added. Or H T O 9 5 3 10^2 10^1 10^0 9 5 3

Counting in Binary The binary numbering system is a base 2 numbering system. Employs the digits 0-1 which represents an “off” and “on” position respectively. Instead of columns being 10^0, 10^1, 10^2 .. They are expressed as 2^0, 2^1, 2^2

Example 1 Convert the decimal number 115 to binary. Answer: 01110011 1

Example 2 Convert the decimal number 259 to binary Answer: 100000011 Base 2 2^8 2^7 2^6 2^5 2^4 2^3 2^2 2^1 2^0 256 128 64 32 16 8 4 2 1

Example 3 Convert the binary number 11101010 to decimal. Answer: 2^7+2^6+2^5+2^3+2^1 or 128+64+32+8+2 = 234 Base 2 2^7 2^6 2^5 2^4 2^3 2^2 2^1 2^0 1

IP Address

IPv4 Header Source: http://mattiasgeniar.be/2010/04/09/how-ipv6-headers-are-formed-compared-to-ipv4

What is an IP address? Formal Definition: Uniquely identifies host machines on a network. This identifier is used when sharing resources with other hosts in a network. Formal Definition: An IP (Internet Protocol) address is a unique identifier for a node or host connection on an IP network. An IP address is a 32 bit binary number usually represented as 4 decimal values, each representing 8 bits, in the range 0 to 255 (known as octets) separated by decimal points. This is known as "dotted decimal" notation. (St. Xavier’s College, Kolkata). Example: 140.179.220.200

IP Address Structure An IP address consists of four sections Each section (or octet) is 8 bits long which comes out to a total of 32 bits. Each octet can range from 0 to 255. The lowest being a value of 00000000 and the highest 11111111 respectively.

IP Address Structure 5 Classes of IP address A B C D and E Class A reserved for governments and large companies 1st octet 0 - 126 Class B reserved for medium companies 1st octet 128 - 191 Class C reserved for small companies 1st octet 192 - 223 Class D reserved for multicasting 1st octet 224 - 239 Class E reserved for experimentation/research 1st octet 240 - 255

IP Address Structure Private IP ranges: 10.0.0.0 through 10.255.255.255 172.16.0.0 through 172.31.255.255 192.168.0.0 through 192.168.255.255 These address ranges are used for Private internal networks. http://tools.ietf.org/html/rfc1918 As a result they are not routable on the Internet. NAT translates a private IP address to a public routable address

Types of Addresses Network Address – The IPv4 address block assigned to a network. Think of it as a collection of end-devices belonging to a club Broadcast Address – Special address in each network that allows an end-device to communicate with all others in the same network Host Address – The “usable” addresses assigned to end-devices that belong to a specific network Subnet Mask (SM) – 32-bit number that masks an IP address, and separates an address into a network and host portion.

IP Address Structure The Class of the IP address and subnet mask (SM) determine which part of the address belongs to the network and host. The network portion is assigned and the network administrator determines the host portion through subnetting. Ex. 192.169.1.34 with a subnet mask of 255.255.255.0 How do we determine the network and the host portion of an address? One method is to write the subnet mask out in binary

IP Address Structure Ex. 192.169.1.34 with a subnet mask of 255.255.255.0 How do we determine the network and the host portion of an address? Each 1 is part of the network address. Each 0 is the host portion of the address. 255 11111111 00000000 N H

IP Address Structure With that in mind. How do we tell what network an IP address is part of? The answer: By using a bitwise AND operation Question: Given an IP address of 193.111.10.250 and a subnet mask of 255.255.255.128. Determine the network this address belongs to 11000001 01101111 00001010 11111010 AND 11111111 10000000 Answer Decimal 193 111 10 128

Classful Subnetting In this scenario, the SM is fixed for the entire organization Borrow bits from the subnet mask. However, in this scheme, the SM once chosen is a fixed length. This is known as a contiguous addressing scheme For instance, 193.111.10.0/25 is a class C network address. We have LANs that require 68, 32 hosts respectively. Network Address HR BC 193 111 10 .10.1 - .10.126 .10.127 128 .10.1 - .10.254 .10.255 … N shhhhhhh Bit Map

Variable Length Subnet Masking (VLSM) IPv4 has its limitations Adjust the subnet mask length by borrowing additional bits from the host portion of the SM That is, subnet the subnet Done to conserve addressing space If all addresses are not assigned then there is much waste Solution: Borrow additional bits from the host portion of the address

Classless Inter Domain Routing (CIDR) Is a way of notating an IP address and its corresponding Subnet Mask (prefix) Ex. Net: 192.168.1.0 SM: 255.255.255.0 can be expressed as 192.168.1.0/24 The /24 corresponds to the number of digits set to the ‘1’ position in the subnet mask CIDR makes it possible for route summarization Instead of keeping a routing entry for each network summarize

Classless Subnetting Involves VLSM addressing We can borrow additional bits in the subnet mask to meet the demands of our network Done to conserve addressing space If all addresses are not assigned then there is much waste

Classless Subnetting Given a network address of 150.161.0.0/16 Create an addressing scheme for the following LAN requirements: LAN A (350) hosts, LAN B (200) hosts, LAN C (30) hosts, LAN D (30) hosts. Can use the .0 subnet. LAN Network CIDR Host Range BC Subnet Mask 150 161 /16 255.255.0.0 A /23 .0.1 - .1.254 .1.255 255.255.254.0 B 2 /24 .2.1 - .2.254 .2.255 255.255.255.0 C 3 /27 .3.1 - .3.30 .3.31 255.255.255.224 D 32 .3.33 - .3.62 .3.63

Sources IPv4 http://en.wikipedia.org/wiki/IPv4_Header#Header http://www.techiebird.com/networkclass.html http://en.wikipedia.org/wiki/Bitwise_operation http://www.orbit-computer-solutions.com/Types-of-IP-addresses.php http://www.iplocation.net/tools/netmask.php http://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing Binary Concepts http://packetlife.net/blog/2010/mar/4/teaching-binary-and-other-bases/ http://l3d.cs.colorado.edu/courses/CSCI1200-96/binary.html http://www.swansontec.com/binary.html Subnetting Concepts & Practice http://www.techrepublic.com/article/ip-subnetting-made-easy/6089187 http://www.9tut.com/subnetting-tutorial https://beausanders.org/main/index.php?option=com_content&view=article&id=72&Itemid=83