Communication systems Flashcards
SSL
Secure sockets layer, encrypts data sent between website and browser
Handshaking
sender and receiver decide on a set of protocols for transmission
Synchronous transmission
continuous and consistent transfer of data
Asynchronous transmission
data is transmitted in regular intervals with gaps
Intranet
private network, secure environment
Extranet
private network extended to allow access to or from selected external organisations
Internet
completely public network to share and access information
Telecommuting tools
- video conferencing
- electronic mailing
- chat and messaging software (e.g. microsoft teams)
- public switched telephone network
Telecommuting (advantages)
- cut down on travel time
- improved motivation
- opportunity for greater work/life balance
Telecommuting disadvantages
- may not have proper accomodation to work effectively
- personal distractions - procrastination
- lack of social interactions - isolation
Volume test data
used to test if system can perform as intended even with large amounts of data, designed for systems that are subjected for large amounts of data
Role of a network administrator
- manage users
- manage logon procedures
- instillation of hardware and software
- maintenance and backups
Network diagram main components
Wired:
- lines to indicate cabling
- topologies
- boxes for PC
- switcher
- router
- cloud
Wireless:
- UTP
- cloud
- router
Email notation (BCC and CC)
BCC –> blind carbon copy, can see which CC have received the email but the CC do not know that the BCC have received the email
CC –> carbon copy, can see which CC have received the email
Microwave transmission media
- Requires a clear line of sight between the sender and the receiver
- Can be a very secure form of communication
- Signals are usually transmitted over short distances (these would usually require only two antennae)
Satellite transmission media
- Works best when there is a clear line of sight between the sender and receiver
- Operates over larger distances (as the satellites are orbiting around the Earth)
Star topology
all nodes are linked to the central server but not to each other
Benefit:
- Even if one node fails, the other clients and the server will be unaffected
- Central server helps to minimise data collisions
This is because star topologies use an Ethernet protocol and CSMA/CD to manage the flow of data
Disadvantage:
Topology is expensive to set up
Ring topology
Does not require a central server and all nodes are connected to each other
Benefits:
- Does not require as many nodes as star topologies and a central server → very effective for small networks
- Uses Token ring to manage the flow of data and minimise collisions as there are less nodes as compared to star topology
Disadvantages:
If a cable or node stops working then the whole system doesn’t work
Functions of a network operating software
- Supporting workstations
- Application sharing
- Controlling printer access
Gateway
connect networks with different transmission protocols
Bridges
connect networks with the same transmission protocols
Identifying suspicious email addresses
- Domain name is not a standard domain name → @__domain name
- Includes some form of threat → if you don’t update now, you must pay $200
- Does not include information of how to contact the business
Ethernet
- Allows data to be transmitted simultaneously
- Uses (CSMA/CD)
- When collision detected, device stops transmitting
- Used in star topologies
Token Ring
- Data collision → two devices send data at the same time
- Continually passes tokens between nodes
- Used in ring topologies
Network topologies (list)
- bus topology
- star topology
- ring topology
- hybrid topology
- mesh topology
Bus topology
- All devices are attached to a direct line
- This is called the bus
- Each device has a unique ID
- Each device is connected to every other device
- Can still operate if one node fails
Bandwidth
The range of frequencies that can be transmitted through a medium (Higher bandwidth = increased capacity to transmit data)
Error correction methods (list)
- retransmission
- error correction protocols
- symbol substitution
- error correction code
Error detection methods (list)
- parity check
- checksum
- cyclic redundancy check
- TCP protocol
Thin client vs. Fat client
thin client –> doesn’t have much processing power, relies on the server for power and storage.
fat client –> has enough processing power on its own, has its own storage which it can store and retrieve from
Nodes in a network
Node refers to the devices present in the network.
Client - server model
Client - relies on a server/network (device or program) - can’t do anything without that connection
Server - provides a specific resource for a network (e.g. file location, database, internet, email or printer
Simplex transmission
Communication occurs in one direction only.
Half-duplex transmission
Communication can occur in both directions but never at the same time.
Full duplex transmission
Communication can occur in both directions and at the same time.
Synchronous transmission
Continuous and consistent transfer of data. Type of serial transmission.
Asynchronous transmission
Delays in the transmission of data. Data is transferred at irregular intervals.
