Networks Flashcards
(51 cards)
What is a symbol in communication?
A particular pattern of bits represented by a signal, e.g., 1110
What does Baud rate measure?
The number of signal changes in the medium per second.
What is the relationship between bit rate and Baud rate?
Bit rate = Baud rate x Number of bits per signal.
How is bit rate defined?
The number of bits transmitted over the medium per second, often measured in bits per second
What does bandwidth refer to in communication?
The range of frequencies that a communication medium is capable of transmitting, expressed in Hertz.
What is latency in communication?
The difference in time between an action being initiated and its effect being noticed, measured in milliseconds.
What typically happens to latency with increased distance?
Latency usually increases with distance.
What is a protocol in communication?
A set of rules relating to communication between devices.
What is serial data transmition
Data is sent one bit at a time along 1 line.
Used for long range communication
What is parallel data transmission
Data is sent along parallel wires one bit along each line
Advantages,
disadvantages of serial data transmition
ADV
Cheaper,no skew or crosstalk,more reliable.
DIS
Takes longer
Advantages,disadvantages of parallel data transmition.
ADV
More bits sent per second,
DIS
Data going to other branches (crosstalk), different times of output (skew), expensive.
Synchronous transition
A clock signal (shared by sender and reciever) data sent then.
Asynchronous transmition
Start,end bit is opposite.
Start bit tells driver clock to synchronise with sender clock.
Then data sent
Then end bit tells clock that the processor can then processor the data sent.
Physical network topology
Actual archtecture of a network.
Star topology
Clients have a connection to a Hub. Hub receives packets and send then to correct recipients.
Bus topology
Uses a single cable called a backbone. Terminators are at the end.
Logical network topology
This refers to the flow of data packets in a network.
Client-server nerworks
One or more servers provided services and the clients request the services from them and the server responds to them.
ADV
Security, central management,
DIS
Expert needed to make and manage
Peer-Peer networking
Services are provided by clients and are all equal. All have some importance and resources as shared and stored.
ADV
Cheaper,no powerful server,easy to set up
DIS
Security, if one doesn’t work nobody can use it.
What is packet switching
Packets are data that is sent over the network
The object is split into packets and then sent over the Internet by the router.
Every time it passes through a roster it counts as a hop.
What does a packet contain
Sender IP address
Recipient IP address
Time to live (number of hops)
Packet contents
Sequence number (the order of them)
What is a router
They send packets in the fastest way (lowest hops). They hold INFO about fastest routes and is usually updated.
What is a gateway
When 2 networks use different protocols.
It strips everything away leaving the contents. It then gives knew sending and recent addresses.
