1. What is the process
Process is the basic unit program fragment execution, resource allocation and scheduling run
2. What is the thread
The thread is the smallest unit in the process of performing operations
3 difference, process and thread
(1) it can only belong to a thread of a process, but a process can have multiple threads
Dependence between the communication process communication mechanism (2) to maintain the process, the communication between threads via read / write variables to achieve a thread
4. What is the port
A host can simultaneously run multiple processes, ports are the only distinguishing mark process
In the network communication, other hosts you want to access the host's a process, we need to know the IP address of the host and port
It's like looking for someone besides him to know where the country provinces + + + Street + cells cities and counties have to know where he's outside the cell house numbers
Here's country cities and counties + + + Province + cells street name is the IP address, house number that is port
5. What is a socket
Process through software called a "socket" interface message to the network transceiver
Sockets network layer belonging to the concept, understood as IP + port
6, port status
| CLOSED | The socket is not enabled, netstat can not find the state |
| LISTEN | The socket is listening for connections |
| SYN_SENT | Active connection socket has been sent syn, ack each other but did not receive responses |
| SYN_RECEIVED | Has received other syn response, but did not receive ack syn own sent |
| ESTABLISHED | Connection is established |
| CLOSE_WAIT | Remote socket is closed, local socket is waiting close |
| FIN_WAIT_1 | Socket is closed, the connection is shutting down |
| CLOSING | Socket is closed, the remote socket is closed |
| LAST_ACK | Remote socket is closed, waiting for the local socket closed |
| FIN_WAIT_2 | Socket is closed, waits for the remote socket closure |
| TIME_WAIT | This socket has been closed, the socket is waiting for remote shutdown transmission |
Reference material
[1] "process, the difference between the thread"
[2] "The difference between the socket and the interface"
[3] "Port Status Description, three-way handshake"