How websites work

Question 1

What is a client-server model?

Client-Server model

Answer 1

The client-server model in computing refers to a structure where clients, like your computer, smartphone, web browser, or desktop application, send requests to servers. These servers could be services like a website hosting server or Amazon Elastic Compute Cloud (Amazon EC2), a virtual server type. The servers deliver the requested services or information across a network. This model is foundational to the web and many other network services.

In essence, the client-server model outlines that clients are reliant on servers to function and that servers are responsible for managing and providing specific services to those clients.

Question 2

What is a Client?
What is a Network?
What is a Server?
What is an IP?

Answer 2

• A client is a computer or application that requests services or resources from another system, usually a server. Client: for instance, your web browser like Google Chrome or Firefox when you are browsing a website.
• A network is a group of computers or devices connected together, allowing them to share resources and information. Network: for example, the Internet, which connects millions of computers and servers around the world.
• A server is a computer or system that provides services or resources to other computers, typically called clients, over a network. Server: e.g., the computer system that hosts a website like www.google.com or services such as Amazon Elastic Compute Cloud (Amazon EC2), a type of virtual server.
• An IP address is a unique string of numbers and/or letters that identifies a device on a network. Example: 192.168.1.1.

Question 3

What is a server composed of?

Answer 3

Question 4

IT TERMINOLOGY
What is a Network?
What is a Router?
What is a Switch?
What is ** DNS** and a DNS server ?

Answer 4

• Network: cables, routers and servers connected with each other
• Router: A networking device that forwards data packets between computer
  networks. They know where to send your packets on the internet!
• Switch: Takes a packet and send it to the correct server / client on your network
• DNS (Domain Name System): It’s a system that translates human-friendly domain names, like www.google.com, into numerical IP addresses, like 192.168.1.1, that computers use to communicate.
• DNS Server: A server that stores a database of public IP addresses and their associated domain names, and responds to queries against its database. It serves as a directory service for translating friendly domain names into IP addresses.

Domain Names: These are the human-friendly addresses (like www.google.com) we type into a web browser. They are easier for people to remember than numerical IP addresses.

Queries Against Its Database: When you type a domain name into your browser, a request (or query) is made to the DNS server to find the corresponding IP address for that domain name.

Serves as a Directory Service: Like a phonebook, a DNS server maintains a directory. It maps domain names (like a person’s name) to IP addresses (like their phone number) so when you look up a website by its domain name, it can find the right IP address.

Question 5

Traditionally, how was infrastructure built ?

Answer 5

Traditionally, IT infrastructure was built through an on-premise model. This involved companies purchasing, owning, and maintaining their own physical hardware, such as servers, routers, and storage systems.

This infrastructure was typically hosted in a dedicated room or a data center, where it could be properly controlled, cooled, and maintained. Servers were configured and managed by the organization’s own IT staff, and any scaling or updates required physical changes to the hardware.

Applications were installed directly onto these servers, and data was stored either on local machines or on network-attached storage devices.

This setup provided a high level of control over the data and systems but came with significant upfront costs for hardware and ongoing costs for maintenance, energy use, and IT staffing. It also lacked the scalability and flexibility of modern cloud-based solutions.

You do not need to lear this by heart. Just the jist of it.

Question 6

What are the problems with traditional IT approach?

Answer 6

• Pay for the rent for the data center
• Pay for power supply, cooling, maintenance
• Adding and replacing hardware takes time
• Scaling is limited
• Hire 24/7 team to monitor the infrastructure
• How to deal with disasters? (earthquake, power shutdown, fire…)