Network Addressing

Exam Objective: Explain the properties and characteristics of TCP/IP Objectives Exam Objective: Explain the properties and characteristics of TCP/IP Exam Objective: Explain common TCP and UDP ports, protocols, and their purpose

What is a computer network address? Pm video 5:33 A network address serves as a unique identifier for a computer on a network When set up correctly, computers can determine the address of other computers on the network and use these to send messages to each other One of the best known forms of network addressing is the IP address Another form of addressing is the MAC address

MAC Address vs IP Address A MAC address is embedded at the factory and is used to uniquely identify a network adapter MAC addresses are required for networking to work Many network adapters allow you to override the MAC address, but even so it still identifies your computer on the local network A MAC address is kind of like the color, size and shape of your physical mail box IP addresses are assigned manually or by software and are used to uniquely identify a network device on a network IP addresses are also required for networking to work The network has to know what computer to send data to An IP Address is kind of like your postal address

IP Address MAC Address

Static Address vs Dynamic Address A Static IP address is one that is manually and permanently assigned to a computer or device A Dynamic IP address is assigned by a server each time a device (or client) connects to the network A DHCP (dynamic host configuration protocol) server assigns addresses to a DHCP client that is requesting an address

Ipv4 vs ipv6 pm video 11:55 An IP address can have 32 or 128 bits Internet Protocol version 4 (IPv4) uses a 32-bit address to identify a network connection IPv4 provides over 4 billion unique addresses, but there is now a shortage of IPv4 IP addresses Internet Protocol version 6 (IPv6) was created partially due to the shortage of IPv4 addresses IPv6 uses a 128-bit IP address, which provides 340 undecillion addresses

Ipv6 addresses 2001:0000:0B80:0000:0000:00D3:9C5A:00CC An IPv6 address has 128 bits written as 8 blocks of hexadecimal numbers separated by colons Each block in an IPv6 address is 16 bits Example: 2001 in hex is 0010 0000 0000 0001 in binary Leading 0s in a 4-character hex block can be eliminated Example: The IP address above can be simplified: 2001:0000:B80:0000:0000:D3:9C5A:CC If blocks contain all zeros, they can be written as double colons, but only one set of double colons can be used Example: The IP address above can be further simplified: 2001:0000:B80::D3:9C5A:CC

Routers for example don’t see IP addresses the same as we do IPv4 Addresses An IPv4 address is represented as four decimal numbers separated by periods, such as 192.168.1.8 An octet is each of the four decimal numbers and can be any number from 0 to 255 The dotted decimal format was created only to make working with IP addresses easier Routers for example don’t see IP addresses the same as we do An IPv4 address is actually 32 bits long and is made up of 4 groups, which are each 8 bits long

Binary to decimal & decimal to binary Each number in the dotted decimal format (192.168.1.0) represents an 8 bit binary number (192 decimal is equal to 11000000 binary) and each 1 or 0 is a single bit The largest possible 8-bit number is 11111111 binary which is equal to 255 decimal The largest possible decimal IP address is 255.255.255.255 (known as a broadcast address) 11111111.11111111.11111111.11111111 (binary)

IPv4 addresses are divided into 3 main classes IPv4 Classes IPv4 addresses are divided into 3 main classes used to identify a specific network and a specific host With class A addresses the first octet identifies the network and the last three identify the host With class B addresses the first two octets identify the network and the last two identify the host With class C addresses the first three octets identify the network and the last octet can be used to identify the host

Subnets pm video 9:10 Large networks can be divided into smaller networks called subnetworks or subnets Subnetting allows you to create multiple logical networks that exist within a single Class A, B, or C network If you do not subnet, you are only able to use one network from your Class A, B, or C network, which is unrealistic and not very efficient Consider a Class A Network - It is not practical to have 16 million nodes in the same domain

Subnet Masks The subnet mask identifies which part of an IP address is the network id and which is the host id Subnet masks help a device know if an IP address is part of it’s network or belongs to another network Open a command line window and type “ipconfig” without switches and press enter This will display the IP address assigned to your computer It will also show the subnet mask and default gateway

Default subnet masks for classes of IP addresses Subnet masks can be viewed as a group of ones followed by a group of zeros In a subnet mask if the bits are turned on (or are 1’s), the corresponding bit is used for the network If the bits are turned off (or are 0’s) the bit is for the host Default subnet masks for classes of IP addresses

Public Address vs Private Address A public IP address is one that is available to the Internet and a private IP address is one that is used on a private network You can use a router with NAT (Network Address Translation) redirection for Internet access NAT is a protocol that substitutes the public IP address of the router for the private IP address of a computer that needs to communicate on the Internet

Private IP Address Classes and Ranges