Web Architecture

Miscellaneous notes related to web architecture, drawing on course material and past learning:

The World Wide Web

The global supply and demand of web pages is known as the world wide web.
Web pages are a type of hypermedia document, consisting of text, multimedia and hyperlinks.
Web services are services that make use of web pages, and web application models.
Client-Server, Peer-to-Peer, and Cloud-Computing, are examples of web application models.
Web pages have url addresses, including a domain name .
Web pages that share a domain name are known as a website.
ICANN is an organisation that governs the assignment of domain names to websites.

Requests and responses on the world wide web are handled by webserver and browser software.
Browsers are types of software that render web pages, and handle user interactions with them.
Webservers are types of software that provide web content, in response to requests sent from browsers.
Google Chrome is an example of a browser, while Apache is an example of web server software.
Browsers are capable of intepreting HTML, CSS and Javascript languages when rendering web pages.
HTML is a markup language, that provides the DOM of the web page.
CSS is a styled sheet language, that provides the presentation details of DOM objects.
Javascript is a programming language, that provides event handling dynamics using DOM objects.
W3Schools.com is a website that provides reference material for HTML, CSS, and Javascript.
Communication between browsers and webservers is governed by the internet protocol suite.

The internet protocol suite is a suite of protocols designed to enable communication over the internet.
There are 20+ internet protocols, and multiple ways to categorise them, including the OSI model, and the TCP/IP model.
GeeksForGeeks give an overview of the OSI model and TCP/IP model for internet protocols.
Examples of protocols used on the world wide web include IP, HTTPS, and TCP.
The IP protocol is the assignment of IP addresses to any device connected to the internet.
The HTTPS protocol is the use of HTTP request and response codes, and TLS cryptography, for client-server web services.
The TCP protocol is the use of a TCP header on each data packet transported across the internet, to prompt feedback.
Useful Python libraries for handling web protocols include: socket, scapy and requests.
Examples of other internet protocols in use include ARP, BGP, DHCP, ICMP and UDP.
The ARP protocol is a switch mechanism for associating MAC addresses of physical devices, to IP addresses.
The BGP protocol is an AS mechanism for sharing routing information.
The DHCP protocol is a router protocol for configuring devices on a network.
The ICMP protocol is the use of data packets with ICMP codes for network diagnostics.
The UDP protocol is the use of a small UDP header on each packet transported across the internet, to indicate transportation damage.