Computer science wjec gcse- communication

Advantages of networks

Share; software, data/files and hardware. able to access data. easier to comunicate and have a backup

What is a network

Number of computer systems connected together

Disadvantages of networks

Expensive (initial cost and network management) . security problems.

Two types of networks

LAN and WAN

What is a LAN

Local area network where the computer systems are relitvaly close

What is WAN

Wide area network and the computer systems are relatively distant

4 different network topologies

Bus, ring, mesh, star

What is a bus network

The bus has one main cable that data travels along. It has terminators at the end

The benefits of bus network

Easy to implement, quick set up, cost effective

Drawbakcs of bus networks

Difficult to troubleshoot, performance degrages with new computers, if there is a porblem with the main cable evrything goes wrong, low security, data collisions are more likely

What is a mesh network

Each computer system is connected to eachother

What is partial mesh network

Each computer system is connected to one other system

Advantages of mesh

Multiple nodes can send data at once, handles high traffic well, each connection carries its own load, backup paths if a node fails, faults are easy to detect, easy to add more devices

Disadvantages of mesh network

Hard to install and configure, expensive cabling, many redundant connections, difficult setup and maintenance

What is a ring network

Computer systems connected in a ring or a loop, the data packets are sent around in this ring

Advantages of ring network

Data is transffered quickly, consistent speeds, simple data transfer, additional nodes have little impact, prevents network collisions

Disadvantages of ring network

If any system fails cant be transmitted efficiently, if there is a porblem with the main cable it all goes down, hard to troubleshoot, hard to add new nodes

What is a Star network

Computr systems connected to a central node such as a node

Advantages of star network

easy to set up, add more computers easy, good performance, minimal collisions, better security

Disadvantages of star network

expensive to install (cabling), extra hardware such as a hub is needed

What is an NIC and why is it used

Network interface card is a physical hardware port needed to connect a computer system to a network

What affects wifi connection

Distance between device providing and computer system using, atmosphere conditions as well (heavy rain in particular)

What is circuit switching

A network technology that provides temporary but dedicated link between two nodes

Advantages of circuit switching

reliable, once connected it is fast and usually error free

Disadvantages of circuit switching

It takes time to establish, should anywhere on the route fail itll break

What is a packet

Collection of data that is transmitted

What’s contained inside a packet

Source address, destination address, information used to re assemble to OG form, tracking info, data itself, a checksum

What is routing

Selecting paths along a network to send packets

What is a router

It forwards data via the best route and acts as a gateway between LAN and WAN

What is a hub and a drawback

Broadcasts data to all connected devices, only one link at a time (congestion)

What is a switch and a benefit

Direct data packets only to the intended device, reduces congestion

What is a bridge

Connects two networks using the same protocol

What is a gateway

Connects two networks using different protocols

What is a wireless access point (WAP)

A hub for wireless connections, bridges wireless devices to a wired network

What is a MAC address

Media access control address is a unique hexadecimal number given to any communication device, it is permanent and doesn’t change

What is an IP address

Allocated to a computer system on a network used to uniquely identify systems on a network

What is a DNS server

Distributed database to match IP addresses to computer system resources

Name common protocols

Handshaking where two devices establish readiness to communicate, indicator of a finished message, how to indicate the message was received, error checking, agreement of the data comparison method used

What is TCP/IP (transmission control protocol/Internet protocol)

IP is a protocol that sets out the format of packets and an addressing system, TCP is allowing packets to be sent and received between systems

What is HTTP/HTTPS

Used to transfer multimedia web pages over the internet

What is FTP

File transfer protocol is used when copying one file from a location to another location via the internet, usually used for larger files

What the the 5 layers to the TCP/IP stack model

Physical, data link, network, transport, application

What is the physical layer

Transmits raw data, consists of hardware, setting up and maintaining a link

What is the data link layer

splits data into frames, checks data is received correctly and manages confirmation of data arriving

What are data frames

Packets of data with extra information added to help send data

What does the network layer do

Handles addressing and routing of data between devices

What do routers do on the network layer

Pick the best path of data to reduce congestion

What does the transport layer do

Making sure data is transferred reliably in the correct order without errors

Where is the transport layer used

in the sending and receiving computers

What does the application layer do

Lets software use the network by providing an interface

How does data travel from host 1 to host 2

Data moves down the 5 layers from host 1 then through routers which only uses 3 layers (network, data, physical) Then up the 5 layers

What protocols are in the application layer

HTTP (hypertext transfer protocol), SMTP (simple mail transport protocol) ,FTP (file transfer protocol)

What protocols are in the transport layer

TCP (transmission control protocol)

What protocols are in the network layer

Internet protocol

What protocols are in the data link layer

ethernet protocol

What protocols are in the physical layer

Physical connection using a NIC or router to connect to internet

What is the Wi-Fi protocol

Wireless networks using 802.11 protocols to transmit data via electro magnetic waves other than cables

What is email protocols

You need an email client and a mail service often provided by your ISP, the client and server exchange information using specific protocols

What is the POP3 protocol

Used for receiving emails, it stores mail in a single file on the server till the client logs on, Once the client logs on its stored on that device

What is the IMAP protocol

Stores emails on a mail server, allowing them to read and handle them as if they were stored locally, allows them to make folders, store drafts and delete message

What is the SMTP protocol

Used to send email to a mail server, can only be used to send