HTTP

URL vs URI??

HTTP/1

• came in 1996
• built on top of TCP
• every request to same server requires a separate TCP connection

HTTP/1.1

• came in 1997
• introduced keep-alive mechanism (prevents unnecessary 3-way handshake for each request between same client and server)
• added http pipelining
• TLS/SSL is optional

HTTP/2

• came in 2015
• introduced http streams
• introduced push capability (allow updates to be sent to client)
• TLS 1.2+

HTTP/3

• came in June 2022
• uses new protocol: QUIC instead of TCP
  • QUIC is based on UDP
  • introduces stream as the first class citizen in transport layer
  • QUIC uses concept of connection ID which helps in switching networks
• It solves the issue of having to switch multiple connections (3G to Wifi to any other network) which is very sluggish
• It is secure by default
• TLS 1.3