Fundamentals of Communication and Networking Flashcards
What is serial transmission?
The method of transferring one bit at a time through a medium. Uses a single wire.
What is parallel transmission?
The method of transferring blocks of data simultaneously. Uses multiple wires.
What is synchronous transmission?
The receiver and transmission clocks are synchronized with each other.
What is asynchronous transmission?
The receiver and transmission clocks do not need to be synchronized
Explain what start and stop bits are.
In asynchronous transmission, a start bit alerts the receiving computer of the arrival of a character. The stop bit signals the end of the character.
What is baud rate?
the number of signal changes per second
What is bit rate?
The number of bits per second that can be transmitted along a digital network.
What is bandwidth?
A range of frequencies within a given band, particularly those used for transmitting a signal.
What is latency?
The time delay between the moment something is initiated and the moment its effect begins.
What is a protocol?
A set of rules that allow two devices to communicate.
Describe a physical star topology.
A topology for a LAN where all nodes are individually connected to a central connection point, like a hub/switch. A star takes more cable than a bus, but the benefit is that if a cable fails only one device will go down.
What are the advantages of a star topology?
- It’s easy to add/remove clients to and from the network
- Each cable has just one device communicating over it, eliminating the possibility of collisions
- The failure of one cable doesn’t affect the performance of the rest of the network
What are the disadvantages of a star topology?
- If central hub fails, all communication over the network is stopped
- Expensive to install thanks to the amount of cable required
Describe a bus network topology.
A physical bus connects client to a single cable called a backbone. A device called a terminator is placed at either end of the backbone.
Advantages of a bus network topology.
- There is no central hub, reducing the chances of a network failure and decreasing the cost of installation
- Inexpensive to install as a minimum length of cable is required
Disadvantages of a bus network topology.
- If backbone fails, the entire network becomes unusable
- The backbone is used for communication by multiple clients, introducing the risk of collisions
- Packets are sent through the shared backbone, allowing every client on the network to see packets that aren’t intended for them
Describe a logical bus network topology.
A network physically wired in star topology can behave logically as a bus network by using a bus protocol and appropriate physical switching.
What is a peer-to-peer network?
No shared server. Services are provided by the clients themselves and every client has equal status, each computer can act as both a client and a server.
Advantages of a peer-to-peer network.
- More cost effective, there is no need for a powerful server to provide services
- PTP networks are easier to set up and maintain than client-servers
Disadvantages of a peer-to-peer network.
- All clients providing services must be running in order for the network to be fully operational. If computer responsible for managing storage is turned off or faulty, non of the clients on the network can access their files.
- No centralized management of security
What is a client-server network
One or more central servers provide services to the clients on the network. Servers are connected to the network in the same way as clients, but are often more powerful machines than the clients.
Advantages of a client-server network.
Central management of clients and security on the network which can improve security
Disadvantages of a client-server network.
Requires a fair degree of expertise to set up and manage
What is WiFi?
A facility that allows computers, smartphones or other devices to connect to the internet or communicate with one another wirelessly within a particular area.
What does CSMA/CA stand for?
Carrier Sense Multiple Access with Collision Avoidance
What is CSMA/CA?
A network multiple access method in which carrier sensing is used but nodes attempt to avoid collisions by transmitting only when the channel is sensed to be ‘idle’.
What does RTS/CTS stand for?
Request To Send/Clear To Send
What is RTS/CTS?
An optional mechanism used by many wireless networking protocols to reduce frame collisions introduced by the hidden node problem.
