It means that sockets are 'Full-Duplex', meaning that both server and client can both send and receive information while the connection is open.
Yes, socket.io uses HTTP for both fallbacks for tcp events, and to support for functions like namespaces and rooms src
The server receives the event as a .on('event', callback) property.
The clients receive the event as above.
Unhandled events are simply ignored.
By creating listeners for all events, then deciding based on some other state whether to do anything with the event.
Socket - one of the endpoints in a two-way data sharing connection over TCP.
Web Socket - communications protocol dictating full duplex communication over a TCP connection.
Socket.io - javaScript library for handling realtime communications with web sockets.
Client - Party connecting to a server for data exchange.
Server - Party connecting to a client, handling management and relay of data exchange.
OSI Model - Open Systems Interconnection model characterizes and standardizes the communications protocol of the internet in 7 layers.
TCP Model - Transmission Control Protocol model is a concise version of the OSI model for describing communication procedures. 4-layers.
TCP - the Transmission Control Protocol is the protocol used on top of IP to support reliable transmission of data between two parties by requiring an established connection between sender and receiver.
UDP - User Datagram Protocol is another IP protocol that does not require an established connection channel before sending data.
Packets - a formatted unit of data. Essentially the smallest unit of data passed around the internet.