networks

- Operating System - File structures: partitioning and formatting - Cables: ethernet vs fibre, key terms

what is the topology of a network

the way a network is laid out

what is a star network

all devices and computers are managed from a central point, the switch

what does the switch do

manages all the traffic on the network

diagram of star network

what is a client and what do they do

the terminals where users log in

clients retrieve documents and software from the server

any device which connects to and uses the server/eq;

what is a printer

a shared resource, managed by a server

The star network can link to a server through a router.

diagram:

define server

a computer which has been set up to hold resources centrally, such as the documents of user profilewha

what do profiles enable users to do

log in to any client on the network and access your personal resources, which are all stored centrally on the sever

examples of servers:

insert server after each word:
database, file, mail, print, web, game, app

what does a router do

connects different networks together simultaneously

what is a terminal

A point at which data enters or leaves a network

advantages vs disadvantages of a star network

advantages:

• very reliable - if one cable/device fails the others will keep working

• high-performing (no data collisions)

disadvantages:

• expensive to install

• extra hardware required (e.g. hubs, switches) which adds to cost

• if a hub or switch fails, all the devices connected to it will have no network connection

what is an Edge router

The outermost connection point between an internal network and an external network is known as an edge router

what is a node + what can they do x3 small

any connection point in a network (can recognise, process and forward data transmissions)

what is client-side processing

Processing of transmissions and received data conducted on a client is client-side processing

what is server-side processing

Processing of transmissions and received data on a server is server-side processing

what is the user profile

A user profile is a set of information pertaining to one user.

e.g. file permissions, security settings (password), available services

how does data on a network move, in p______s

in packets

each packet is sent individually and then reassembled into the original file at the receiving end

what 3 parts are is the data packet made up of

headers, the payload (data being transmitted) and a trailer.

what is the header and what happens to it when it reaches the receiver

header identifies the source and the destination of the data packet. The header is stripped off the packet when it reaches the receiver.

what is the trailer and what may in contain

if _____ fails, what must happen

trailer uses a few bits to indicate the end of the packet, and it may contain verification. If the verification fails the data packet may need to be retransmitted.

what does an IP address mean for a device on a network.

what form does it take

 the digital addresses of devices on a network.
internet protocol
They take the form of 4 denary numbers between 0 and 255, separated by dots. IP addresses are the LOCATION of a device on a network

Servers usually have ___ IP addresses so that…

what else could be given an IP address

STATIC IP addresses

so that devices always know where to find them

(also other resources that always need to be found, like shared printers, could also be given static IP addresses)

what is a MAC address

how is it formed

who is it assigned by

the unique identifiers of a device on a network. They are a group of 6 pairs of hexadecimal digits, separated by colons or dashes

assigned by a manufacturer when the device is first produced

media access control

define protocols

A protocol is a set of rules for communication between two devices.

what is the primary use of a port number

to transfer the data between a computer network and an application.

a port is a ____ address assigned for ___ ______ in the computer system that receives data from the network

LOGIAL address assigned for EACH APPLICATION

what does OSI model stand for, what does it describe

Open Systems Interconnection

describes how data is transmitted from one device to another. (could be public or private or internet).

what are the 5 OSI layers?

1 - Physical

2 - Data link

3 - Network

4 - Transport

5 - Application

what is Layer 1 responsible for

physical:

Physical transmission hardware - cables (like CAT-6/ethernet) and ports

what does Layer 2 do

Matches sending/receiving addresses using MAC addresses & Ethernet protocol

a protocol on Layer 2: Prevents data collisions by ensuring only one packet can arrive at an address at a time

…

Ethernet is a network protocol that controls how data is transmitted over a Local Area Network (LAN). Ethernet defines when to transmit, transmission speeds and media.

….

what does Layer 3 do

Uses IP to route data packets between networks via routers

describe specifically how it works with the route tables and stuff (probs unofficial)

• Routers hold tables of IP addresses

  • use them to send data packets to the right address.

• If table does not hold the required address, they pass the data packet to another router.

• generally 64 attempts before the data packet is discarded.

  • TimeToLive (TTL) variable keeps track of the number of attempts and is decremented by one every time the data packet is passed to another router.

what is layer 4

what does TCP stand for

transport layer:

where data is broken down into packets

Transmission Control Protocol

what's Layer 5's purpose?

what is it for web vs email

Application layer

Handles application-specific protocols like HTTP (web) and SMTP (email)