Networks

define network

a set of interconnected devices (primers, computers + servers) designed to: share resources and exchange data

define network protocols

a set of rules for communication between devices over a network

def standard

a set of guidelines or framework that govern how tasks should be performed

Why are standards needed in a network?

• interoperability

• reliable communication

• scalability

What is the DNS

translates domain names to IP addresses- when a user enters the URL, the DNS resolves it to the servers IP address

def the internet

a global network of interconnected networks that communicate using standard protocols (TCP / IP)

def world wide web

a collection of web pages + resources accessed over the internet using a web browser

def backbone

a high - capacity main connection in a network that carries large amounts of data between smaller networks

def circuit switching

involves creating a communication connection between 2 endpoints for the duration of a transfer of data

def packetising

a process where a large message is divided into smaller, manageable units called packets

What are packets composed of?

• a header

• a payload (actual data)

• a footer

what is the purpose of headers?

contain information necessary for the packets delivery

def packet switching

a networking communication method that breaks down data (large files) into smaller packets + sends these packets along different routes, then reassembling them at their destination

ADV of packet switching

efficient use of network resources as packets can follow different paths ot their destination - using more of available bandwidth

more reliable - if a single packet fails to reach its destination > only that packet needs to be resent > not the entire datastream

lower costs > shared network resources

DIS of packet switching

not ideal for real time services like video calling which requires a steady stream of data without delays

packets can arrive out of order, requiring reassembly + error - checking

potential for congestion in network

def circuit switching

a communication method where a dedicated communication path is established between 2 devices for the duration of their conversation + all packets sent along same route

ADV of circuit switching

ideal for real - time services (e.g: phone calls) due to a constant + steady data transmission rate

no delays as a dedicated path is established

data arrives in order as it follows the same path

DIS of circuit switching

less efficient as resources remain allocated during the whole conversation, even if no resources are being sent

more costly due to the dedicated line requirement

less flexible + scalable as adding new devices can be complex

def protocol layering

the way network protocols are divided into layers, each of which perform specific functions

Why use layering?

• reduces complexity

• standardisation

• independence of layers

• easier fault finding

What are the 4 layers in the TCP / IP model?

• application layer

• transport layer

• internet layer

• link layer