Are these 2 concepts refer to the same thing? Do they have difference?
In my opinion, they are different, and socket connection is based on tcp connection. A socket contains an IP address and port and it could only connect to another socket, but an IP address and port in the same machine could be connected with many other IP addresses and ports with TCP connection. Is this right?
Socket is layer 5 protocol (Session) in OSI Model and is not dependent on underlying layers which means it can be over TCP, UDP, MPTCP, ... (Layer 4 - Transport layer protocols). Socket connection is used for continues exchange of data between nodes (it creates a session between them) but TCP connection makes a reliable transmission of data segments between nodes.
Sockets are defined as an application programming interface (API) for communication usually between two processes, but not limited only to this. They involve library functions your application will link with, system calls, and implementation part of the operating system kernel. The most common types of socket APIs are Berkely socket and Winsock (Windows).
Other classification of socket for the type of access they provide is:
In Linux, Unix, and Windows, there are TCP, UDP, and Unix domain sockets. The other types of sockets mentioned above are implemented in Linux and I don't know if they exist in Windows.
TCP connection is a TCP concept. It connects two endpoints, usually two processes (or one process to itself) and it's defined by (IPAddress1, Port1, IPAddress2, Port2). The TCP connection is established after TCP 3-way handshake.
In TCP a socket is defined by the elements of a TCP connection between two processes (IPAddress1, Port1, IPAddress2, Port2). However, there can be also a listening socket. This is a socket that a allows a process to listen for connections established from other processes through the network.
