Introduction to Networking with LANs and WANs
IP addresses
Objectives Be able to define what an IP address is Identify and describe the IP address classes Identify and describe network and host portio
ns of an IP address Describe what a broadcast address is used for Describe what private IP addresses are used f
or
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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
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Activity 11. 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
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ipconfig results
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The network part of the address Is used to route the packet to the correct network
i.e. 194.66.170 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 (http://www.internic.net/) to ensure that all address attached to the Internet are unique
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Host addresses
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Address representation (IP v4) An IP address is a 32 bit value
In theory this gives over 4 billion possible addresses (232) 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
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Address classes
Address 127.*.*.* is a reserved address to indicate loop back i.e. communicate with the device sending the
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Address classes
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Address classes
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Activity 2Look at the following IP addresses. Identify
which class they belong to:
192.168.1.254 64.240.32.28 10.1.27.252 130.254.254.253 127.0.0.1 145.10.10.256 254.100.100.155
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Class C
Class A
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
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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
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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
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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 - 255.0.0.0 Class B - 255.255.0.0 Class C - 255.255.255.0 Example
192.5.5.35 255.255.255.224 192.5.5.35/27
You cannot skip bits!19/04/2316 Richard Hancock
Activity 31. 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, 296
4. 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
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Activity 41. Build the network topology below in the
diagram within the lab
2. Assign 192.168.1.254 to PC0 and 192.168.1.253 to PC1
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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
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Questions... ...are there any?
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End!
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