TCPTransmission Control Protocol — a reliable, connection-oriented protocol used on the internet./IPInternet Protocol — the addressing and routing layer that moves packets across networks. splits networking into IPInternet Protocol — the addressing and routing layer that moves packets across networks. (routing packets between hosts) and TCPTransmission Control Protocol — a reliable, connection-oriented protocol used on the internet. (reliable byte streams). Every HTTPHyperText Transfer Protocol — the protocol browsers use to request and receive web pages. request, SSHSecure Shell — encrypted remote login, command execution, and file transfer over networks. session, and database connection still rides this stack. The flag day meant all ARPANETAdvanced Research Projects Agency Network — the U.S. research network that pioneered packet switching and became a precursor to the internet. hosts had to switch at once or lose connectivity — no gradual migration.

TCPTransmission Control Protocol — a reliable, connection-oriented protocol used on the internet./IPInternet Protocol — the addressing and routing layer that moves packets across networks. flag day is the birth moment of the interoperable internet protocol suite.

It let independent networks interconnect and scaled beyond a single research WAN.