System Design

Client-Server Model

Client : A machine or process that reuqests data or service from a server.
Server : A machine or process that provides data or service for a client, usually by listening incoming calls.
Client-Server Model : The paradigm by which modern systems are designed, which consists of clients requesting a data or service from server/s providing data or service.

IP Address

An address given to each machine connected to public network. IPv4: 4 numbers seperated by dots a.b.c.d.
- 127.0.0.1: localHost
- 192.168.x.y: private network

Port

In order for multiple programs to listen to new network connections on same machine without colliding, they use a port to listen on.
Ranges from 0 to 65535 (2^16)
- 0-1023: system ports
- 22: secures hell
- 53: DNS
- 80: HTTP
- 443: HTTPS

DNS

Short for Domain Name System, it describe the entities and protocols involved in translation from domain names to IP address

Network Protocol

IP

Stands for Internet Protocol. This protocol outlines how almost all machines-to-machines communication should happen in the world. Other protocols like TCP, UDP & HTTP are built on top of it.

Less stoage capacity
Inconsistent transfer of data
Random order of tranfer of IP packets

TCP

Stands for Transmission Control Protocl. Allows for ordered, reliable, data delivery between machines over the public internet by creating a connection. TCP is usually implemented in kernel, which exposes sockets to application that they can use to stream data through an open connnection.

HTTP

The Hyper Text Transfer Protocol is a very common network protocol implemented on top of IP. Client makes a HTTP requests and server responds with a response.