what happens when you load a video on youtube

[patmuchiri]

When you load a video on YouTube, several key technologies and processes are involved:

DNS Request:
Your browser sends a DNS request to resolve "www.youtube.com" into an IP address.
The DNS server responds with the IP address of YouTube’s servers.

TCP/IP:
Your browser establishes a TCP connection with YouTube's server using the IP address.
Data is exchanged using the TCP/IP protocol suite.

Firewall:
Network firewalls inspect incoming and outgoing traffic to ensure it meets security policies.
They allow or block traffic based on predefined rules, protecting YouTube’s infrastructure.

HTTPS/SSL:
Your browser and YouTube's server establish an encrypted connection using HTTPS.
SSL/TLS encryption ensures the data exchanged is secure and private.

Load-balancer:
A load-balancer distributes incoming requests across multiple YouTube servers.
This ensures efficient use of resources and prevents any single server from being overwhelmed.

Web Server:
The load-balanced request reaches a web server that handles HTTP(S) requests.
The web server processes the request and forwards it to the appropriate application server.

Application Server:
The application server runs YouTube’s backend code to handle video streaming requests.
It processes the request, performs necessary computations, and interacts with the database.

Database:
The application server queries the database to fetch video metadata, user preferences, and other relevant data.
The database server responds with the requested information.

Video Delivery:
The application server prepares the response, including video data fetched from YouTube’s Content Delivery Network (CDN).
The response is sent back through the web server, load-balancer, and over the HTTPS/TCP connection to your browser.

Playback:
Your browser starts receiving the video data and begins playback.
Additional video data is streamed progressively as you watch the video.