Networks Flashcards
What is a computer system?
Two or more computers , that are CONNECTED together that are able to exchange data with each other. Allowing software and hardware to be shared.
What are the advantages of networks?
🟢communication eg: emails & text messages
🟢file sharing , eg: stored centrally and worked upon centrally
🟢hardware sharing , eg printers , making it more cost effective
🟢user account allow you to log in from any device
🟢installing software centrally , takes less time
What are some disadvantages of networks?
🟣expensive to set up as a lot of hardware is required. eg: NIC cards, switched , cables
🟣vulnerable to hacking and malware which can spread to networked computers
🟣hard to maintain and install , may require employing a specialist
Describe a PAN
Personal area network:
- very short range(few meters)
- cantered around 1 user
A network that is spread over a very small area used to connect personal devices
🟡don’t require additional hardware, can used them on the move
🟡often wireless technology eg: Bluetooth
Describe a LAN
Local area network
🟡small geographical area located on a single site
🟡wired or wireless
🟡owned an maintained by the organisation
Describe a WAN
Wide area network
🟡A combination of LANs in different geographical locations
🟡expensive as they need to hire infrastructure
🟡under collected or distributed ownership
What is a WLAN?
A wireless local area network
What is a wireless network?
A network that connect computers to a network through electromagnetic ☢️ radiation
What is a wired network?
Makes use of physical wire to connect computers to the network
Advantages wireless 🟢networks:
🟢Wireless are cheaper to set up.
🟢Wireless also requires less information and installation is automatic.
🟢wireless can add people more easily
Advantages of wired networks🔴
🔴wired have a larger transmission speed, higher bandwidth, more reliable
🔴wired are more secured. As physical connection is needed to intercept data
🔴wired have no interference from other Wireless networks or physical obstructions like walls
What is a NIC?
Network interface card, a piece of hardware inside a device that allows it to be connected to devices
What is a WAP?
Wireless access point
Needed in wireless networks
Basically a switch needed to connect devices wirelessly
What are switches?
Used to connect devices within a LAN to form a network
Device can access the switch simultaneously
What are routers?
Transmit data between different networks
Used to connect to the internet
Compare fibre optic cables and copper cables
Fibre: transmits dat as light.
More expensive but higher bandwidth
No interference and very large distance
Copper :
cheaper but have lower bandwidth
Describe a star topology
All devices are connected to a central switch or server, controlling the network. Can be wired or wireless
What is a node?
A device connected to a network
Star network pros and cons
✅if a device fails the network is unaffected
✅fewer data collisions as all devices can transmit data at the same time
✅easier to add devices
✅packets only sent to intended devices
❌expensive as it requires a switch and other hardware
❌problem with switch then the whole network is affected
Describe a bus network
Use a single ‘backbone ‘ cable to connect all devices.
Two terminator at the end to stop data reflections (interference)
Pros and cons of Bus networks
✅if one device fails the network remains unaffected
✅cheap to set up and maintain
✅not dependant on a switch
❌frequent data collisions slowing the network down
❌unsuitable for large networks as too many data collisions
❌network fails if the backbone cable is broken
Define network protocols
A set of rules that determine how devices communicate the transmission of data across a network
Describe Ethernet
🔌A family of protocols
🔌 manages data transfer for wired LANs
Describe HTTP
Hyper text transfer protocol
Used by web browsers to access websites / communicate with web servers .
Describe HTTPS
Hyper text transfer protocol secure
A more secure version of HTTP, as it uses encryption . The web browser will check the web servers security certificate and ensure it is legitimate. This means that it is not possible to eavesdrop
Describe FTP
File transfer protocol
Used to access , edit and move files between devices on a network, other devices
eg: to access files on a server from a client computer
What does IMAP do?
IMAP- internet message access protocol:
Retrieves emails from a server
What is TCP and how does it operate
Transport control protocol
Splits data into numbered packets to be sent over a network
What is UDP and how does it operate?
User diagram protocol
Splits data into packets to be sent over a network, without numbering them
Describe the differences between UDP and TCP
TCP is more reliable
UDP is more faster and efficient used for live video streaming
Describe Wi-Fi
🔴A family of related protocols
🔴wireless data transfer on WLANs(wireless lAN)
Describe IP and it’s purpose
Internet protocol,
🟣give them an IP address ,
🟣used to route the journey for packets by according to traffic
Responsible for packet switching
An IP adresss is a number code gIven to every device in the network
What is the 4 layer TCP/IP model?
Application layer
Transport layer
Internet layer
Link layer
What does the application layer do , and what are some examples?
Network applications like web browsers or email programs operate
Eg: HTTP, HTTPS,FTP,SMTP.IMTP
What does the transport layer do, and what are some examples?
🔵sets up communication between 2 hosts
🔵make the size of packets
Eg:TCP,UDP
What does the internet layer do, and what are some examples?
🔵addresses and packages the data for transmission
🔵routes the packets across the network
Eg: IP
What is the link layer, and what are some examples?
Passing data over a physical network, data sent as electrical signals over cables , wireless and other hardware
🔵network hardware is located
What is authentication, when would it be used?
🟣takes one or more specific data from a user
🟣only allows access to the system if credentials are valid
Preventing unauthorised access
eg: username and password
What is encryption and when would it be used?
🔢the process of disguising a message so that it cannot be understood by anyone but its intended recipient
Eg: ceaser cipher, web browsers
What is firewall , and when is it used?
🔥 acts as a barrier
🔥 Examines all packets entering and leaving
🔥 identifying potential threats from packets using security rules and blocking unwanted data
Software or hardware
What is MAC address filtering and when is it used?
🔵takes a MAC address for each device
🔵checks to see if it is in the list of allowed , and on that basis gives it permission to connect to the system
What is the purpose of a terminator?
Absorbs signals and stops data reflecting back along the bus
Compare bus and star
🚎 isn’t reliant on central switch/server, ⭐️ will completely fail if central device stops working
🚎 less cabling (no switch) and so are cheaper than a ⭐️
⭐️ all devices can access the switch simultaneously, so there are no data collisions, 🚎 data collisions are common
What does SMTP do?
Simple mail transfer protocol:
Sends emails to a server
What is an IP address?
Identifies devices on the internet
Used by routers to direct the packets to their location
When is UDP deemed better ?
🟡does not establish a connection between the two devices, making transmission quick
🟡does not require retransmission of lost/corrupt packet, making transmission quick
Why is network security important?
🟠prevent cyber attacks(targeting specifics)
🟠prevent unauthorised access
🟠protects data and programs against damage
