1.3 Computer networks, connections and protocols Flashcards
Features of LAN networks
- Small geographical areas
- Connects multiple nodes
- Uses local connections such as Ethernet cables
- Private ownership
- Slightly faster
- Used for smaller businesses
Features of WAN networks
- Multiple geographical areas
- Connects multiple LANs
- Uses wide area connections such as the cloud
- Private or public ownership
- Slightly slower
- Used for global or nationwide services
Factors affecting the performance of a network
- Number of devices connected
- Bandwidth, the amount of data that can be carried through a connection at any one time
- Interference
- Network traffic
- Proximity to WAP
- Latency, the length of time information takes to travel through the network
- Error rate/collisions
Switch
Connects a device on a LAN using MAC addresses
Router
Connects devices on a WAN using IP addresses
WAP
Connects wired networks to wireless devices using their MAC addresses
NIC
Used to connect a device on the network. Each has an individual MAC address
Transmission media
The way in which data is sent between connected devices e.g. copper cables
Features of a client-server network
- A central server backs up all file servers
- Security is controlled by a central server
- All users are reliant on the central server
- Using servers enables businesses to grow to hundreds or thousands of computers and users
Features of a Peer-to-Peer network
- Each computer needs to be backed up
- Security is controlled by each individual member
- There is no central sever
- If one computer goes down, only its services are lost
- Network is difficult to maintain beyond a few computers
How does a DNS work?
- Client sends a DNS request for domain
- DNS checks for domain, the forwards it on to the next DNS till IP and name match on in their database
- Found IP returned to client
- Client requests webpage from web server with matching IP address
Hosting
- Provides database servers
- Backup sites remotely
- More bandwidth
- Monitor servers 24/7
The Cloud
- Services delivered over the internet
- Accessible by any internet connected computer
Advantages of The Cloud
- Can be accessed easily
- Hosting organisations secure data well
- Hosting organisations can back up data in different servers
- Computing power is not required from the client to access stored data
- Simple to expand
Disadvantages of The Cloud
- Slow for data needs to be requested and transferred over long distances and there is a lot of network traffic
- Subscription data storage can result in the loss of data accidentally
- Personal data not stored by personal database
- Limitations can be used by the service provider
- Loss of internet connection results in a loss of availability of stored data by the client
Advantages of Star Network
- Fast data transfer to the hub as each wire isn’t shared with other computers/A signal doesn’t need to be transmitted to all computers on the network
- If on node/cable fails the other computers aren’t affected
- Easy to add a new node or device
- Fewer data collisions can occur
Disadvantages of Star Network
- Requires additional hardware such as the central switch and network cables
- If the central switch fails the whole network goes down
Advantages of Mesh Network
- No single point of failure, it is resilient
- Expansion and modification can be done without disrupting the network
- Data can be transmitted from different devices simultaneously
Disadvantages of Mesh Network
- Can involve redundant connections
- Expensive to install cabling if using wired connections
- Network administration and maintenance is difficult
Features of Ethernet
- Fast data transfer
- Better physical security
- High range
- Less susceptible to interference
- Physical limitations with portability
- Costly physical installations
- Safety hazards with physical cable
Features of Wi-Fi
- Slower data transfer
- Less secure
- Range relies on WAP quality and interference
- Can move around within range
- Cheaper to set up and add new devices
- Compatible with most devices
Features of Bluetooth
- Very slow data transfer
- Less secure
- Very short range
- Ideal for personal devices and ad-hoc connections
- Low power consumption
Encryption
Used to protect data in case it is hacked or accessed illegally. Doesn’t prevent hacking however renders data incomprehensible without necessary decryption tools
IP address
Changes, used for routing across WANs
Standard
A set of technological specifications that allow devices made by different manufacturers to communicate with one another
Protocol
A set of rules defining how devices communicate and transfer data on a network, ensuring all devices interpret data in the same way
HyperText Transfer Protocol
Used for websites
HyperText Transfer Protocol Secure
Used for websites and encrypts data to restrict access
File Transfer Protocol
Delivers and receives files
Transmission Control Protocol/Internet Protocol
Organises packet transfer down fastest route and reorders them, making sure that none have been lost and resending the message if so. Also routes packages over the internet
Simple Message Transfer Protocol
Sends messages to the server then the internet
Internet Message Access Protocol
Accessed messages from the server appear in your inbox without deleting it, so that it can be accessed by multiple recipients
Post Office Protocol
Takes messages from the server and deletes them
MAC address
Doesn’t change, used for routing across LANs, assigned by NIC
