3b. Networks and Communications Flashcards
What is a switch?
A device that connects several devices together to enable communication to take place. You can do things such as limit the bandwidth on certain ports.
What is a master switch also called?
Backbone switch.
What is a hub?
A hub looks the same as a switch. It is very similar but the data that goes through it isn’t filtered. Data is also more susceptible to interception. Collisions can also occur.
What is a WAP?
Wireless access point. A hub that communicates by wireless instead of having physical connections.
What is a NIC?
Network interface card. Enable a computer to be connected to a network using a cable. More modern computers have these built in on the motherboard. Each NIC has a MAC so that each card is unique.
What does MAC stand for?
Media access control.
What is a wireless network interface card?
To connect to a WAP, a device needs a wireless NIC.
What is a router?
An advanced version of a switch. Mainly used to connect a LAN to a WAN. Were once used only by big companies, now a household item.
What is a repeater?
Signals deteriorate after long cables, so a device is required to extend the range.
What is a bridge?
Used to connect two LANs together. It’s similar to a router but it does not store the addresses of devices connected to it.
What is a server?
A powerful computer that performs functions on behalf of clients connected to it. There are many different types of server and the size an functionality of a network will dictate how many are needed.
What is a file server?
A file server stores files available on the network. It will normally have storage areas set aside for each user on the network that are only accessible to those users.
What is an application server?
An application server stores software for use across the network. The application can either be run from the server by a client computer, or the software installation files can be stored on the server so they can be deployed to client computers.
What is a disadvantage of an application server?
A lot of network traffic if run from the server. If the installation files are taken from there it requires the clients computer to have the right processor, memory, etc.
What is a mail server?
Receives all incoming emails and then allocates them to the appropriate inbox. If the user sends an email it goes to the server and then to somebody else on the LAN/WAN or to the internet. It also filters out spam.
What is a proxy server?
Maintain access to the internet within an organisation. Can store cache so websites are quicker to load for other clients. A firewall. Filter access to webpages, so some are blocked.
What is a print server?
Manages access to printers within the LAN. Reduces the processing burden on client computers. All print jobs will go in a queue. Can prioritise some in the queue. Can provide reports of who has printed what.
What is a back up server?
Backs up all data on a network so that individual users do not have to do it. Usually connected to tape drives. Back up jobs will be scheduled so that they run automatically every day, usually over night.
Name 4 types of optical communication methods.
Infrared, fibre, optic and laser.
What is infrared?
Only works at short distances, no more than 10 metres. Requires direct line of sight. Bandwidth is restricted to 115.2kbpd.
What uses infrared?
Remote controls. Used to be main wireless communication before bluetooth (for phones, laptops, etc.)
Describe fibre optics.
Data travels at the speed of light. Used in LANs where distances of more than 100 metres need to be covered. Virgin Media use fibre optics to broadcast cable television signals and to provide broadband.
What is laser communication?
Two laser devices in direct line of sight to each other. Each sends and receives a laser beam. Travels at speed of light. Only works in line of sight. Used in laser tag.
Name 2 wireless communication devices.
Bluetooth and radio.
