Section 9 - communication and networking Flashcards
Serial Transmission
Data is transferred 1 bit at a time down a single wire.
Parallel transmission
Data is transferred several bits at a time using multiple wires.
Bandwidth
Measure of the capacity of the channel in which the data is being sent down
Bit Rate
Rate at which data is actually being transmitted
What does 1 baud represent
1 electronic state change per second
Latency
Time delay that occurs when transmitting data between devices
What are the 3 causes of latency
Propagation latency
Transmission latency
Processing latency
Propagation latency
The amount of time it takes for a logic gate within a circuit to transmit the data
Transmission latency
The amount of time it takes to pass through a particular communication
Processing latency
The amount of time it takes data to pass around a network depending on how many devices or servers it has to pass through
Asynchronous data transmission
Data is transmitted between two devices that do not share a common clock signal.
Synchronous data transmission
The pulse of the clock of both devices are in time and the data is transmitted in accordance with this pulse.
FTP
File Transfer Protocol
What is the defintion of TCP/IP and what does it do
(Transmission Control Protocol/ Internet Protocol)
Handles the routing and re-assembly of data packets.
NIC + what it does
(Network Interface Card)
Allows devices to connect to a network
Network
Devices that are connected together to share data and resources
Star Topology
It connects devices in a network where each workstation has a dedicated cable to a central computer or switch.
Advantages of star topology
-Fast connection speed
-Will not slow down as much when many users are online
-Fault finding is easier
-Relatively secure
-New clients can be added without affecting the other clients
-If one cable or client fails, only that client is connected.
Disadvantages of star topology
-Expensive to set up
-If the cable fails then that client may not be able to receive data.
-Difficult to install
-Server can become congested
Bus topology
A network layout that uses one main data cable as a backbone to transmit data.
Advantages of bus topology
-Cheap to install
-Easy to install
-Easy to add new clients
Disadvantages of bus topology
-Less secure
-Transmission times get slower as more users are on the network
-If the main cable fails, all clients are affected
-Less reliable
-Difficulty in finding faults
Peer-to-Peer network
All devices in a network share resources between them.
MAC address
(Media Access Card)
A unique code that identifies a particular device on a network.
What is the purpose of CSMA/CA and what does it stand for
-Carrier Sense Multiple Access with Collision Avoidance
- It allows various devices to transmit data at high speeds without interfering with each other.
What does the CSMA/CA protocol do
Before each frame of data is sent, the device using the protocol checks to see if the transmission medium is idle and if its free it will transmit the data but if it is busy it will wait a random amount of time before trying to send it again.
What is RTS/CTS and what does it stand for
-Request to Send/ Clear to Send
-The RTS node sends a message to the recieving mode and if a CTS message is recieved it transmits the data otherwise if no CTS message is recieved it waits then sends it again.
SSID meaning and use
(Service Set Identifier)
A 32-character code that acts as an identifier in the header allowing it to be transmitted to the correct WLAN
How to keep a wireless network secure
-Change the SSID from the default value and hide it in transmission
-Ensure that all devices are WiFi protected access
-Use strong encryption
-Create a white list of MAC addresses
Internet
A global network of networks
URL
(Uniform Resource Locator)
method of identifying location of resources
DNS
(Domain Name Server)
A server that contains domain addresses that associate with IP addresses
PORT
Used to identify a particular process or application on a network
what does POP3 do and what port is it
-Fetches email from the email server
-Port 110
what does SMTP do and what port is it
-Checks for incoming email on an email server
-Port 25
NAT
(Network Address Translation)
It matches up private IP address with public ones
Port forwarding
a method of routing data through additional ports.
