Networks Flashcards
Advantages of networking computers
Communication
monitoring user activity
controlling and updating workstations
roaming
sharing information
resource sharing
software streaming
Disadvantages of networking computers
Dependence - if the main server fails, every device connected to the network will also fail
Security issues
Initial installation can be expensive
Malware
Advantages and disadvantages of wired networks
Advantages:
More secure as the network is only accessible with a physical cable connection
Less interference
Generally has faster data transfer compared to wireless networks
Disadvantages:
More time needed to install
High installation and replacement costs
Inconvenient due to many cables
More maintenance due to larger infrastructure
Advantages and disadvantages of wireless networks
Advantages:
Cheap and easy to install
Multiple devices can be connected without any additional hardware
Disadvantages:
Slower compared to a wired network
Quality is disrupted due to obstructions
Security issues such as hacking - not as secure, as radio signals can be picked up by anyone
Lower bandwidth
Define a computer network
two or more devices that are connected together and can communicate with each other
Explain the different types of cabling for wired networks, including advantages and disadvantages
Describe and compare common LAN topologies
Bus: consists of one long cable with terminators at either end. All the nodes on the network are then connected to this cable by their own separate cable
Advantages:
-cheap and easy to set up as it doesn’t require much cabling
Disadvantages:
-since all data travels along the central cable there is increased chance of data collisions which can cause a network to slow with large numbers of devices connected
-all data will travel along the main cable, meaning other nodes “see” it, presenting a security risk.
-if the main cable fails, the network will fail
Star: there is a central hub/switch, and all other devices are connected to this one device using its own cable
Advantages:
-High performing - tends to be faster than a bus network as there are fewer data collisions.
-Reliable - if one node fails then the others should continue to work.
-Secure (if a switch is used) as the data is only sent to the devices that should have access to it.
Disadvantages:
-Uses a lot of cable so is expensive to set up, and requires more expertise than a bus network.
-Requires additional hardware in the form of a hub or switch which also makes it more expensive.
-High reliance on the central hub/switch. If this fails, the network fails.
-Security issues if a hub is used, as this will send data to all nodes connected to the network.
Define the term network protocol
An agreed way of communicating over a network
Explain the full form, purpose and use of common network protocols including:
Ethernet
WiFi
Transmission protocols (TCP and UDP)
IP
HTTP
HTTPS
FTP
email protocols (SMTP and IMAP)
Ethernet: family of related protocols that deal with how data is sent along ethernet cables
Wifi: family of related protocols that deals with how data is sent through wireless connections
TCP (Transmission Control Protocol) and UDP (User Datagram Protocol): both ensure that packets are addressed and tracked through the network, making sure they arrive at their destination safely. However, if the packet doesn’t arrive as they should, TCP ensures that it is resent correctly by the sender, whereas with UDP the packets aren’t resent. Therefore UDP is faster and used by organisations where speed > quality
IP (Internet Protocol): manages the addressing of the data packets, and is responsible for adding the sender and receiver IP addresses to each packet, as well as determining which data packets are addressed for that machine
HTTP (Hypertext Transfer Protocol): responsible for sending requests for and receiving web pages
HTTPS (Hypertext Transfer Protocol Secure): responsible for sending requests for and receiving web pages, but provides an encrypted version of HTTP for more secure web transactions
FTP (File Transfer Protocol): used to upload or download (i.e. transfer) files between computers and the internet
SMTP (Simple Mail Transfer Protocol): used by mail servers to send and receive mail from all other mail servers around the world
IMAP (Internet Message Access Protocol): controls the download/upload of emails to and from the mail server. It creates a copy of the email on the device that you have, but also leaves a copy on the mail server so that it can be viewed on other devices as well
Describe the 4-layer TCP/IP model
Application layer: this is where the network applications, such as web browsers or email programs, operate.
Transport layer: this layer sets up the communication between the two hosts and they agree settings such as the size of packets.
Internet layer: addresses and packages data for transmission. Routes the packets across the network.
Link layer: this is where the network hardware such as the NIC (network interface card) is located. OS device drivers also sit here.
Identify which protocols are used in each layer of the TCP/IP model
Application layer: HTTP, HTTPS, FTP, IMAP, SMTP
Transport layer: TCP/UDP
Internet Layer: IP
State the similarities/differences between hubs and switches
Both devices are used to connect parts of a network together. Switches are intelligent devices that are able to send data packets to just the node that requires it, whereas a hub is passive, and just copies data packets to all ports it is connected to.
How is authentication effective as a security method?
-can be used to prove that someone is who they say they are
-prevents unauthorised access
-commonly in the form of a username and password
How is encryption effective as a security method?
-turning data into an unreadable format that can only be decrypted by a key
-plain text is converted into cipher text and can only be converted back into plain text by the person with the key
How are firewalls effective as a security method?
-a piece of software that controls what information is allowed in and out of a network
-barrier between a trusted and untrusted network
-blocks unwanted data packets
