Networking Objectives Understand what hardware is required for networking and what function each piece of hardware performs Cables Network interface card (NIC) Hub Switch Wireless access point Wireless interface card (WIC)
Networking What is a network? A computer network is where many computers are connected together. Networked computers can share files, offer services (such as email) and allow communication. The biggest network in the world is the internet!
Networking Connecting computers There are two ways we can connect computers. Wired and wireless. Wired connections tend to be more common as they are more reliable. However as wireless is becoming faster and more reliable more people are using it. Especially for mobile devices and laptops. You will look at what hardware is needed for both wireless and wired connections. You will also look at how a network could contain both wired and wireless connections.
Networking Wired connections Wired connections use cables to connect computers to the network. The most common type of connection is a Cat-5, also known as twisted pair. It is known as twisted pair as it contains 4 pairs of wires all twisted together in pairs. (see the bottom right image) Twisting the wires reduces electric interference and increases reliability. Cat 5 cables can run at speeds ranging from 10mbit/s to 10Gbit/s. The faster the speed the shorter the cable must be.
Networking NIC A network interface card (NIC) is used to connect a computer to a network using a cat-5 cable. The interface card may be built into the motherboard. The connection will look like the image in the bottom right. One end of the cat-5 cable will be plugged in here and the other would be connected to a hub, switch or a router. You can not connect two laptops together using one cat-5 cable.
Networking Hub A hub is a device which allows several computers to be connected together. The number of computers it can support is based on the number of connections, or ports, it has. A 8 port hub can support 8 computers. 16 port hub can support 16 and so on. Packets sent to a hub are sent to every other computer connected to the hub. This is known as a broadcast. Computers that receive a packet not intended for them will ignore it.
Networking Hub in practice Packet A packet is sent to one port on the hub.
Networking Hub in practice Packet Packet Packet Packet Packet The packet is then duplicated and sent to all ports.
What is a NIC and cat-5 cable What is a hub and what does it do? Networking Activity Make notes on – What is a NIC and cat-5 cable What is a hub and what does it do?
This is much more efficient. A switch uses less network bandwidth. Networking Switch A switch looks a lot like a hub and behaves in a similar way. It allows several computers to be connected together using ports. The biggest difference is how it deals with packets which are sent to it. When a packet is received by the switch it will look at the destination IP address. It will then forward on the packet to the correct port rather than to all of them. This is much more efficient. A switch uses less network bandwidth.
Networking Switch in practice Packet A packet is sent to one port on the switch.
Networking Hub in practice Packet The packet is then forwarded onto the destination port only.
What is the difference between a switch and a hub? Networking Activity Make notes on – What is a switch? What is the difference between a switch and a hub?
In order for wireless to work you need a wireless access point. Networking Wireless Wireless means you can connect to a network without the need for cat-5 cable. Wireless connections on computers tend to be referred to by their standard. 802.11.N is currently the fastest wireless which can support speeds of up to 100Mbit/s. This is much slower than wired which can reach 10Gbit/s. The lower the letter after 802.11 the slower the connection with a being the slowest. In order for wireless to work you need a wireless access point.
Networking Wireless The diagram above shows a wireless router connected to the internet. A number of computers are connected to it wirelessly. In this situation the wireless access point would be the wireless router.
Networking Wireless access point A wireless access point (WAP) is a central point to send and accept wireless transmissions from wirelessly enabled devices. A WAP could be connected to a wired network. Wireless suffers from signal degradation the further you move away from it. Signal is lost due to walls, other devices, distance and even the weather. The lower the signal the slower the connection. If you want a better reception you will need to move closer to the WAP or buy a wireless repeater which will boost the signal.
Networking Activity Make notes on – Wireless access point 802.11.N
Networking Combining wired and wireless It is very common to combine both wired and wireless for a network. Wired is faster but is not always possible to install while wireless can be put in most places but is much slower. Normally mobile devices and laptops would connect wirelessly while desktops and servers would connect using wired. This is how the school has set up it’s network. In the next slide you will see a example of how the school network could be set up. It is simplified with each PC representing a whole room of PC’s
Networking Combining wired and wireless Room 9 Room 11 Room 5 Room 6 Hub Hub switch Wired Wireless WAP Laptops
Networking Activity In groups you need to design a network for a primary school. You should use the document “A network for a primary school” to guide you.