B3 - Issues of transmitting data Flashcards
Types of email protocols
SMTP - Transmit mail to server from client
POP3 - Retireves email from server and download messages to client for online reading
IMAP - Access mail on remote server. Main difference - doesn’t remove mail from server
Protocols for voice and video
calls over the internet
SIP - Create, control and end VoIP connections
RTP - Transfers audio and video over IP-based network
Types of protocols used in web pages
HTTP - Makes connection between web and client, transfers web pages
HTTPS - Secure version of HTTP. Encrypts comms
FTP - Transfer files from computer to internet.
Secure payment systems
SET - When a product is purchased the purchase is sent to the merchant website and card details go to the bank. Payment is authorised and the authorisation is returned to website to complete transaction
Security issues when transmitting data
Sniffing - Malicious user can instruct packet sniffers to inspect all data being transmitted allowing them to gain information such as passwords
Public WiFi are vulnerable but 4G isnt
Hard do to on wired connection
Spoofing - Uses fake credentials to act as another computer. Used to carry out DoS attack by sending masses of data to overload network
Great vulnerability on wireless network
What is bandwidth and what factors affect it
How much data can be transferred from one computer to another in a given time.
High bandwidth is better because more data can be transferred
Online streaming needs high bandwidth and doesn’t need low latency
Factors affecting:
Time of day
Distance from nearest telecommunication Volume of data being transmitted
What is latency and what factors affect it
How long is takes for data packet to transfer over a network
Low latency is better because data can reach destination faster
Gaming needs low latency to allows gamers to react quicker
Whats is Lossy compression
What are the advantages and disadvantages
Permanently deletes bits of data to reduce file size
Used for audio, video and images
Advantages - More reduced than loseless and allows quicker upload/download time
Disadvantages - Reduces quality, using CODEC and if receiver doesn’t have same CODEC it cannot be viewed
What is Loseless compression
What are the advantages and disadvantages
Uses algorithm to pack data
Used for documents and uses WinZip
Has formats for video, audio and images such as PNG
Advantages - Can be decompressed back to normal
Disadvantages - Can be identified as malware and decompressing takes a lot of processing time causing computer to lag
Hardware codecs
Encodes analogue data to digital the decodes to analogue form
Example is sound cards. Encodes voice so computer transmits and decoded data to be played on speaker
Important for VoIP to be able to input voice so otehr person can hear
Software codecs
Compressed audio and video data to be transmitted
Important for VoIP as individual can hold real time conversation
Downsides - Wide variety which leads to problems with compatibility
