Unit 1 1.5 Communication Hardware

What you need to learn: 1.5 Communication Hardware i.e.: hub switch router modem wireless access point combined/hybrid devices characteristics purpose and use Learners should know about different communications hardware and their characteristics. This should lead to an understanding of their purpose and use. Learners should be aware of the difference between a combined or hybrid device, which often provides the functionality of a modem, router, switch and wireless access point in one device, and the individual devices.

What is a network? A network is two or more computers linked together so that they can communicate with each other. They could be connected in several different ways: Cables Wireless Satellites

LAN and WAN LAN WAN Local Area Network. This is a network within a single building. Wide Area Network. This is a network over a wider geographical area such as in different buildings, cities or even countries.

LAN Covers a small geographical area or on a single site. Either wired with Ethernet cable or wireless Why use a LAN: Sharing files is easier as you can work collaboratively Share hardware e.g. printers Shared internet connection Communicate cheaply and easily User accounts can be stored centrally

WAN A WAN can connect LAN’s in different geographical locations. WAN’s may be connected using fibre or copper telephone lines satellite links or radio links. Internet is a big WAN.

Factors which contribute to network performance Bandwidth – amount of data transferred Wired connections vs fibre optic Choice of hardware, topologies and cabling

Hub

What is a hub? A hub is a common connection point for devices in a network.  Hubs are commonly used to connect segments of a LAN. A hub contains multiple ports. When a packet arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packets.

Switch

What is a switch? Switches connect devices on a LAN. Receive data (units in frames) from one device to another Transmit data to a device on the network using the correct MAC address MAC (Media Access Control) address is the computer identity

Router

What is a router? Responsible for transmitting data between networks Always connected to at least 2 different networks. Direct data in packets to their destination. Data packets are how information transmits. Routers are used in homes and offices to connect the LAN to the Internet.

What is a modem? A modem is a device or program that enables a computer to transmit data over, for example, telephone or cable lines. Computer information is stored digitally, whereas information transmitted over telephone lines is transmitted in the form of analog waves.

Modem

Wireless Access Point (WAP) To set up a wireless network you need a WAP. WAP is a switch that allows devices to connect wirelessly. DON’T confuse WAP’s with hotspots. Hotspots are locations where you can connect to a WAP. To connect to the internet devices need wireless capability which is usually built in. if not people can use a USB dongle.

Setting up a network One or more switches / hubs - to link devices together Network cables to connect devices to the switch, etc. A separate wireless access point (or this could be part of the switch) - to allow wireless devices (e.g. laptops or smart-phones) to join the network A router to connect your LAN to the Internet (WAN) A firewall to protect your network from hackers Server(s) to manage network functions such as network security, network file storage, shared resources (such as printers)

ADSL line Asymmetric digital subscriber line (ADSL) is a type of digital subscriber line (DSL) technology, a data communications technology that enables faster data transmission over copper telephone lines rather than a conventional voiceband modem can provide.

ADSL line

ADSL line ANSWER:

Network topologies “Topology” is the word used to describe the shape of a network. There are three main topologies: Bus Ring Star

Ring topology The Ring topology is the simplest and uses the least amount of cabling so it is also the cheapest. All the data travels around the ring in one direction and passes through all the workstations on the network. If a connection is lost, the whole network stops working.

Token Ring

Bus topology The Bus topology uses a central cable which all nodes are connected to. The data travels along the central cable. If one connecter is broken the rest of the network still works but if the central cable is broken then the whole network stops working.

Star topology The star topology is the most robust type of network. The network is controlled by a central “Server” which controls how the data moves around the system. If one cable is broken the rest of the network can still work without any delay. The network will only stop working if the central server stops working.

What is a server? A server is a powerful computer which holds the operating system software to run the network. It allows people to: Log onto the system. Keep files centrally. Send print jobs to the printer. Control internet access and email on the network.

Client server

Peer to peer

Combined/Hybrid Device Topologies: Star, bus, ring network

What is the difference between a combined or hybrid device, which often provides the functionality of a modem, router, switch and wireless access point in one device, and the individual devices? Hybrid Device - hybrid device, which often provides the functionality of a modem, router, switch and wireless access point in one device. This means they are all built within the device. Individual devices will need all of these hardware's separate to connect too.

Worksheet