Introduction to Networking with LANs and WANs IP addresses

Objectives  Be able to define what an IP address is Be able to define what an IP address is  Identify and describe the IP address classes Identify and describe the IP address classes  Identify and describe network and host portions of an IP address Identify and describe network and host portions of an IP address  Describe what a broadcast address is used for Describe what a broadcast address is used for  Describe what private IP addresses are used for Describe what private IP addresses are used for 22/08/20152Richard Hancock

The Internet Protocol  Every machine MUST have a unique address  This is referred to as the IP address  This address is used to route packets of information using TCP/IP to a specific machine  The address is made up of two parts: a network address and a host address 22/08/20153Richard Hancock

Activity 1 1. Start up your PC or laptop and connect it to the college network. 2. Click on the Start button and in the dialog box at the bottom the Start menu type in cmd 3. At the DOS prompt type cd\ 4. Now type in ipconfig and press Enter 22/08/2015Richard Hancock4

ipconfig results 22/08/2015Richard Hancock5

The network part of the address  Is used to route the packet to the correct network  i.e would direct the packet to one part of the Staffordshire university network  Once the packet is within the network  The host part of the IP address is important to direct the packet to actual machine within that network  The network address size changes depending on the size of network in which the host is connected  Class A, B, and C  All network addresses are issued by InterNIC ( to ensure that all address attached to the Internet are uniquehttp:// 22/08/20156Richard Hancock

Host addresses 22/08/20157Richard Hancock

Address representation (IP v4)  An IP address is a 32 bit value  In theory this gives over 4 billion possible addresses (2 32 )  In reality the actual number of available addresses is a lot less than this  An IP address is represented by dotted decimal numbers  In reality within the network the values are represented in binary  As humans we do not use binary, as these are difficult for us to remember  Also it is very easy with a large number sequence to make mistakes when setting the IP address 22/08/20158Richard Hancock

Address classes Address 127.*.*.* is a reserved address to indicate loop back  i.e. communicate with the device sending the request 22/08/20159Richard Hancock

Address classes 22/08/201510Richard Hancock

Address classes 22/08/201511Richard Hancock

Activity 2 Look at the following IP addresses. Identify which class they belong to:        /08/2015Richard Hancock12 Class C Class A Class B Reserved Invalid Class E

Broadcast address  An IP address which is used when communications are required with ALL of the devices with a certain network address  This value is 255 in the host part of the address 22/08/201513Richard Hancock

Private IP addresses  A number of IP addresses have been reserved for private use on local LANS  If you setup a Microsoft windows network it will default to a class C private network IP address 22/08/201514Richard Hancock

Subnets  Subnets allow for a host part of a host address to indicate a subnet  These are smaller local networks within the major network  The advantage is that this allows a packet to be more tightly direct to a host  The disadvantage is valuable host addresses are used to create a subnet  More details about subnets will be given during the course 22/08/201515Richard Hancock

Subnet address  Also 32 bits in length  Indicates which part of the IP address is the network, and which part is the host  Each class has a default subnet mask  Class A  Class B  Class C  Example   /27  You cannot skip bits! 22/08/201516Richard Hancock

Activity 3 1. What are the two parts that make up an IP address?  Network portion/Host portion 2. What are the five classes of IP address, and which ones can be commercially used?  Classes A, B, C, D, E. A B and C can be used commercially 3. For an IPv4 IP address, how many bits are used and what is the total amount of addresses that can be derived?  32 bits – 4, 294, 967, What is the purpose of a subnet?  To identify the network portion of an IP address 5. What will a broadcast IP address actually do?  Transmit to all devices on a particular network or subnet 22/08/201517Richard Hancock

Activity 4 1. Build the network topology below in the diagram within the lab 2. Assign to PC0 and to PC1 3. Test connectivity between the two PC’s 22/08/2015Richard Hancock18

Summary  IP addresses are used to route packets of data throughout a network  IPv4 uses 32 bits  Hierarchical in nature  Classes are A, B, C, D and E  Classes A, B and C are used commercially  Broadcast addresses reach all host machines on a network 22/08/201519Richard Hancock

Questions... ...are there any? 22/08/201520Richard Hancock

End! 22/08/201521Richard Hancock