Network transmission principles

Question 1

What is latency?

Answer 1

Delay between when an application requests and receives data.

Question 2

What is jitter?

Answer 2

Irregular latency. In order for network transmission to work, the two devices must agree on a rate at which data is sent and received

Question 3

How to resolve jitter?

Answer 3

Buffering

Question 4

QoS guarantee

Answer 4

Quality of Service guarantee
Prioritises data packets for others

Question 5

3 types of QoS guarantee

Answer 5

Best effort guarantee: no guarantees

Differentiated service guarantee: some traffic is treated better than other traffic

Guaranteed service guarantee: some network bandwidth is reserved for use only by mission-critical applications

Question 6

4 Internet Protocols

Answer 6

HTTP
HTTPS
FTP
VPN

Question 7

What’s HTTP?

Answer 7

stateless request protocol

Each message is treated as an independent exchange between a client and server and is not reliant on a successful login or menu selection from another page

transports data between client and server

Question 8

What’s HTTPS

Answer 8

HTTP but secure
Uses public key encryption
Public key is sent to web page first through SSL (secure socket layer)

Question 9

What’s FTP?

Answer 9

Used to exchange files

Initated with username and password with the FTP protocol

FTP is NOT encrypted - all files are sent as plain text

Question 10

Whats VPN?

Answer 10

Encrypted connection between two network devices

Establishing VPN is called “tunnelling”

Tunnelling can be implemented by SSL

Question 11

What security features do VPN’s ensure?

Answer 11

integrity and authentication

Question 12

3 methods of data exchange

Answer 12

REST
JSON
XML

Question 13

REST

Answer 13

client-server

Formats data like JSON and XML but also supports CSV

Uses HTTP requests (GET, PUT, POST, DELETE)

It is stateless - each message is self-descriptive which means it can run independently of any messages before or after.

Assumed data will be cached - means that the client can make decisions about data without contacting the server

However this can be easily modified - poor integrity of data

Question 14

JSON

Answer 14

data exchange protocol based on JavaScript

allows a program to establish a connection a live website and interact with online data

JSON API on the client side uses HTTP GET and POST requests

Sends data as JSON object

Question 15

XML

Answer 15

Extension to HTML

Follows a hierarchical structure

To access data, the easiest way is to download the XML file