slr11 - networks Flashcards
What is a network
A group of connected computers
What are the advantages of networks
Users can share files and peripherals
Servers can control security and software updates
Communication over the network is easier
What are the disadvantages of networks
Increased security risks
If the server fails, connected devices may also fail
Computer may run slower if a lot of devices are connected
Why are standards required for devices on a network
Without them devices wouldnt be able to communicate with each other
What are standards
A set of hardware and software specifications that allow manufactures to create products that are compatible with each other
What is the purpose of layers
Separating the process of sending files over a network into several steps so that hardware can be made at each layer
What are the 4 layers of the TCP/IP stack
Application
Transport
Internet
Link
Name a protocol that operates at the application layer
HTTP/S, IMAP
Name a protocol that operates at the transport layer
TCP
What is the name of the protocol that operates at the internet layer
IP
What is used at the link layer
Wi-Fi/Fibre optic
Describe the application layer
The application that the user interacts with
Describe the transport layer
Sets up communication between 2 hosts
Describe the internet layer
Addresses and packages data for transmission
Describe the link layer
Network hardware and connection port standards
Give 2 differences between LANs and WANs
Larger geographical area vs smaller geographical area
WANs have slower transfer speed
What is a URL
the full address of an internet resource. it specifies the resources location name and type so that a browser can request it
What are internet registries
Companies that hold details of all existing website domains
What is a fully qualified domain name
A domain name that includes the host servers name
What does the IP address indicate
Where a packet has been sent to or from
What is an IP address
A unique numerical code that is assigned to a network device
What does a domain name identify
The area or domain that an internet resource resides in
What does DNS stand for
Domain name system
What is linked to every domain name
One or more IP addresses
What is the DNS responsible for
Cataloging all domain names and IP addresses in a series of global directories
Describe a WAN
A network of inter-connected networks that are connected over a large geographical area. Usually defined as one that is relies on 3rd party connections
Describe a physical bus topology
All computers are connected to a single cable
Advantages of a bus topology
Inexpensive to install as it requires less cable
Disadvantages of a bus topology
If the main cable fails then data cannot be transmitted
Performance degrades with heavy traffic
All computers on the network can see all data transmissions
Describe a physical star topology
A network with a central node that acts as a router to transmit messages
Where are the MAC addresses of all the devices stored in a star topology
In the central switch
Advantages of a star topology
If one connection fails, the network still works
There is consistent performance regardless of how much the network is being used
Each station has its own connection to the main server
The system is more secure as messages cannot be intercepted by other stations
It is easy to add new stations to the network
Disadvantages of a star topology
Can be difficult to install and maintain
If the central server fails then the entire network is broken
Describe the difference between physical and logical topologies
A physical topology is the actual layout of the network whereas a logical topology refers to how the data is transferred
Describe a mesh network topology
All computers in the network are connected directly to all other computer
Advantages of a mesh topology
Easy to add new computers to the network
Data does not need to pass through a central switch
Describe circuit switching
A direct link is created between the devices for the duration of the communication
Disadvantages of circuit switching
Bandwidth is wasted when no data is being sent
The devices must use the same transfer rate
Advantages of circuit switching
Packets always arrive in the same order that they are sent which simplifies the process of arranging them at each end
Describe packet switching
Packets are broadcast across a network and are rearranged into order when they arrive at their destination
What is stored in a packet
A header and payload
What is stored in the header
The sender and recipients MAC and IP addresses
The protocol that is being used
The number of the packet in the sequence
The amount of time after which the data is discarded
What is stored in the payload of a packet
The actual data being sent
What is the success of packet switching reliant on
The packets being sent along the least congested route
Why is packet switching faster than circuit switching
All the packets are sent along the least congested route
Why is the senders IP address included in the packet header
Lots of protocols have to send data back to the person who sent it
Describe the application layer
Sits at the top of the stack and provides the interface for users
Describe the transport layer
Uses TCP to establish an end to end connection with the other computer
The data is then split into packets
Describe the internet layer
Adds the source and destination IP addresses
Describe the link layer
The physical connection between network nodes and adds the MAC addresses identifying the NIC cards of the source and destination computers
What happens to packets once they arrive at their destination
The headers on the packets are stripped of in reverse order by which they were added
Describe FTP
A high level protocol in the application layer
