Wired & Wireless Networks, Protocols & Layers Flashcards
All 34 cards in this deck
State two benefits of using a wired (Ethernet) connection instead of a wireless one.
Higher/more consistent bandwidth, and more secure (unlikely to have unauthorised access). Also less interference, so more reliable.
Give two reasons for also allowing a network to be accessed wirelessly as well as by cable.
Users are not fixed to one spot and can connect from anywhere in range; more devices can be connected (more scalable) without the cost of installing extra cables.
What is the difference between Wi-Fi and Bluetooth?
Wi-Fi connects devices to a network/the internet over a larger range; Bluetooth connects a small number of devices over short distances, e.g. a headset to a phone.
Which mode of connection would you recommend for staff who must use tablets while moving around a building, and why?
Wireless (Wi-Fi), because devices are not fixed to one spot and can connect from any location in range.
What is encryption?
The process of disguising a message using a secret code so that it cannot be understood by unauthorised parties.
What name is given to a message before it has been encrypted?
Plaintext — an unencrypted message that is readable to anyone.
What name is given to a message after it has been encrypted?
Ciphertext — an altered message that is unreadable to unauthorised parties.
What is needed to encrypt and decrypt a message?
A key — a secret value used with the encryption algorithm to disguise and recover the message.
Why is data encrypted before it is transmitted across a network, especially a wireless one?
So that if it is intercepted by an unauthorised person it cannot be understood without the key.
True or false? Encryption stops data being intercepted while it is transmitted.
False. It does not prevent interception; it makes the intercepted data unreadable without the key.
What is the format of an IPv4 address?
Four denary numbers (octets) separated by dots, each in the range 0–255.
e.g. 192.154.21.2True or false? 258.0.0.3 is a valid IPv4 address.
False. Each of the four parts must be no greater than 255.
What is the format of an IPv6 address?
Eight groups of four hexadecimal digits separated by colons.
Why was IPv6 introduced to replace IPv4?
IPv4's 4.3 billion addresses have run out as more devices connect to the internet; IPv6 provides vastly more addresses.
What is a MAC address and what format does it take?
A unique serial number assigned to a network interface controller (NIC), written as a string of hexadecimal numbers, used to uniquely identify a device on a network.
Give two differences between an IP address and a MAC address.
An IP address is assigned when a device joins a network and changes from network to network; a MAC address is assigned by the NIC manufacturer and cannot be changed.
What is a standard in computing?
An agreed way of doing things, decided by experts in standard developing organisations, to ensure compatibility and reliability.
Why are standards needed in computing?
So that hardware and software made by different manufacturers can interact and work together reliably.
What is a standard developing organisation?
An organisation that develops and publishes industry-specific standards.
True or false? Standards in computing apply only to hardware.
False. Standards cover software too, such as character sets, file formats and web page languages.
What is a (communication) protocol?
A set of rules for how data is turned into packets and transferred between devices on a network.
Why are different protocols used for different purposes on a network?
Each task (e.g. sending email, transferring files, viewing web pages) needs its own agreed set of rules so devices can communicate correctly.
What is the purpose of TCP/IP?
TCP splits data into packets and reassembles/checks them at the destination; IP routes the packets across networks using IP addresses.
What is HTTP used for?
Transferring web pages between a web server and a browser.
What is HTTPS used for?
Transferring web pages securely — the same as HTTP but the data is encrypted, e.g. for banking or passwords.
What is FTP used for?
Transferring (uploading and downloading) files between computers on a network.
What is SMTP used for?
Sending email from a client to a mail server, and between mail servers.
What is POP used for and what is its key feature?
Retrieving email from a mail server; it downloads the email and deletes it from the server.
What is IMAP used for and what is its key feature?
Retrieving email from a mail server; the messages stay on the server so they can be synchronised across several devices.
What is layering in networking?
Breaking up network communication into separate components or activities, each handling a different part of the communication.
How many layers does the TCP/IP model have?
Four.
State one benefit of using layers in network protocols.
One layer can be changed or improved without redefining the whole communication method, as the other layers are unaffected.
How does layering help with standards in networking?
Standards can be developed for each layer and adapted to new hardware and software over time, so products from different developers work together.
What are the two modes of connection a device can use to join a network?
Wired and wireless.
e.g. Ethernet is a wired connection; Wi-Fi and Bluetooth are wireless connections.