1.3 - Computer Networks, Connections and Protocols Flashcards
What is a Wide Area Network (WAN)?
A network (over a relatively large geographical area) in which the computers communicate using resources supplied by a third party carrier.
What is a Local Area Network (LAN)?
A self-contained network over a relatively small geographical area.
What are the characteristics of a WAN?
Large geographical area; collection of LAN’s; infrastructure between LAN’s leased from telecommunication companies; fibre optics, telephone lines, satellite links used for connection
What are the characteristics of a LAN?
Single site; small geographical area; organisation owns all hardware; fibre-optics, UTP, wireless connection
What affects the performance of a network?
Bandwidth, Latency, Error rate
What is meant by bandwidth?
The amount of data that can be sent and received successfully per second
What is latency?
The length of time a packet of information takes to travel through the network
What is the role of a Network Interface Card (NIC)?
To connect a device to a network.
What is the role of a Wireless Access Point (WAP)?
To allow devices to wirelessly connect to a network.
What is the role of a router?
To route data packets between a LAN and the Internet.
To connect networks, using IP addresses.
To store the IP addresses of the connected networks.
What is the role of a switch?
To connect each node in a network and send data between computers on a LAN.
To use MAC addresses to connect nodes.
To look for the correct MAC addresses as they are being accessed.
What is the Internet?
A collection of inter-connected networks.
What is the Domain Name Service made up of?
Domain Name Servers
What is the role of the DNS in converting a URL into an IP address?
A DNS server translates a web address into an IP address.
When a DNS server receives a request not in its database, the request is passed on to another server until it reaches one with the matching name and IP address.
What is a server?
A powerful computer which provides services or resources required by any clients.
What is a client?
A computer or device that requests services or resources provided by the server.
Types of servers?
File server, print server, email server, web server, database server
What is web hosting?
A service offered by companies in which the facilities need to create and maintain web pages and files for websites are provided.
What is the Cloud?
Services that are remotely delivered over the Internet, for example: to allow the remote storage of files over the Internet.
What are the advantages of the Cloud?
Data and applications can be accessed from anywhere (with an Internet connection); no money needs to be spent on storage for the files as it is done on a remote computer; backing up data is no longer crucial.
What are the disadvantages of the Cloud?
Personal data is stored on another company’s servers; service is unusable if the Internet connection is lost; slow Internet connection results in poor quality of service; people can’t see the level of security and backup.
What is a network topology?
The way in which computers in a network are physically connected.
What are the advantages of a star network?
If a device fails or a cable is disconnected, the rest of the network is unaffected.
It’s simple to add more devices to the network.
High performance and data transmission speed (within the network) as data goes straight to the central device. So all devices can transmit data at once and there are few data collisions.
What are the disadvantages of a star network?
Requires additional hardware (eg: switch), this is expensive.
The network goes down if the central switch fails.
