OCR GCSE Computing, Networks Exam Questions and Answers Latest Update Graded A+

OCR GCSE Computing, Networks Exam Questions and Answers Latest Update Graded A+ Topology - Answers Physical structure and layout of a network. Star - Answers Network topology in which all computers are individually connected to a central node. Most common form of network topology. Adv: Disadv: Mesh - Answers Network topology in which all nodes are interconnected. Often used in disaster areas. Adv: Reliability - all nodes will be able to communicate even with breaks in the cables. Disadv: expensive and complex to set up and maintain. Bus - Answers Network topology in which all devices are connected to a single backbone cable. Data travels in both directions. Adv: simple to set up Disadv: slow due to data collisions. Break in cable means network fails. Protocol - Answers A set of rules used by computers to communicate with each other across a network. HTTP - Answers Hyper Text Transfer Protocol Used to request and transmit web pages over the Internet or other computer network. HTTPS - Answers Hyper Text Transfer Protocol over SSL (Secure Socket Layer) Data transferred over the Internet is encrypted for security reasons. POP - Answers Post Office Protocol Protocol used to retrieve emails from a host and transfer to a client. Obsolete. IMAP - Answers Internet Message Access Protocol Stores email messages on a server but allows end user to view and manipulate messages as if they were local. Synchronises messages across multiple devices. SMTP - Answers Simple Mail Transfer Protocol Protocol to send emails over the Internet Bluetooth - Answers Wireless technology standard for exchanging data over short distances, eg connecting headphones to a device or mobile phone to a car Ethernet - Answers Family of protocols to govern communication across the Internet. FTP - Answers File Transfer Protocol Used to transfer computer files between a client and a server on a computer network. Four layer model - Answers Conceptual model that organises protocols into different layers: Application Transport Network Data Each layer serves the layer above it Breaks communication into manageable pieces, allowing changes to be made to one layer without affecting any others. Companies must make compatible hardware and software so brands can work together. TCP/IP - Answers Set of protocols which dictate how data is sent over the Internet. Packet - Answers Small block of data transmitted from one computer to another. Packet switching - Answers Used by routers to direct packets on the Internet and other IP networks Checksum - Answers Number used to check if a packet of data has been received correctly. IP address - Answers Unique identifier given to a device when it accesses and IP network MAC address - Answers Unique identifier assigned to a device that cannot be changed. Also known as a physical address. 48 or 64 bit binary numbers presented in hexadecimal. Mainly used by Ethernet protocol on LANs. IPv4 - Answers Address presented as a 32-bit binary number, translated into four denary numbers, eg 192.32.6.9 IPv6 - Answers Address presented as a 128-bit binary number, translated into 8 hexadecimal numbers Needed as IPv4 addresses were running out LAN - Answers Local Area Network Network which covers a single site WAN - Answers Wide Area Network Network which covers multiple geographical locations. Internet is the largest WAN Router - Answers Hardware responsible for transmitting data between networks Wifi - Answers Wireless Fidelity Standard used for wireless connections between devices Factors affecting network performance - Answers Bandwidth - the amount of data that can be transferred in a given time Users - too many users or heavy use (streaming video) may slow network Connection media - wires are faster and more reliable than wireless. Fibre optic faster than copper. Wireless subject to interference, physical obstructions (walls) and range. Hardware and topology also play a role Packet header - Answers Contains sender address, destination address and sequence number of packet. Client-server network - Answers Server manages network. Connected devices are called clients. Files and software stored centrally. Client sends requests to the server. Server processes requests and responds. Most of the Internet works on a client-server relationship. Adv: easy to backup, update software, manage security & reliable. Disadv: Expensive to set up, server dependence, potential for server overload Peer-to-peer network - Answers All devices are equal and connect directly to each other without a server. Commonly used in home networks. Adv: easy to set up & maintain, no dependence on server Disadv: no central management, each device must be backed up separately, machines may slow down when accessed by other devices Network Interface Controller (NIC) - Answers Internal piece of hardware allowing a device to