What is TCP echo client?

TCP/UDP Echo Server using I/O Multiplexing. 7. A TCP based client/server system consisting of a server which responds to multiple clients and allows them to issue “ls” and “more” commands to view the directory information and view a file on the server machine.

What is IO multiplexing?

I/O multiplexing means what it says – allowing the programmer to examine and block on multiple I/O streams (or other “synchronizing” events), being notified whenever any one of the streams is active so that it can process data on that stream.

What is echo client and echo server?

An EchoServer is an application that allows a client and a server to connect so a client can send a message to the server and the server can receive the message and send, or echo, it back to the client.

What are the functions are provided by I O multiplexing?

I/O multiplexing is typically used in networking applications in the following scenarios: When a client is handling multiple descriptors (normally interactive input and a network socket) When a client to handle multiple sockets at the same time (this is possible, but rare)

What are the TCP echo server functions?

TCP Echo Server: main Function

• Create socket, bind server’s well-known port. A TCP socket is created.
• Wait for client connection to complete. The server blocks in the call to accept , waiting for a client connection to complete.
• Concurrent server. For each client, fork spawns a child, and the child handles the new client.

What is a TCP client and server?

The “Client” in a TCP/IP connection is the computer or device that “dials the phone” and the “Server” is the computer that is “listening” for calls to come in. The connection between a Client and a Server remains open until either the client or the server terminates the connection (i.e. hangs up the phone).

What is poll function in socket programming?

The poll() function examines the array of file/socket descriptors fds[ ] for n_msec milli-seconds. If some descriptor (e.g., a socket) becomes ready before the before the time out value of n_msec time: poll( ) will return immediately, and: The return value is equal to the number of descriptors (sockets) that are ready.

What is poll and select in networking?

The select() and poll() methods are used for multiplexing network sockets. For instance, a programmer can use these calls to know when there is data to be read on a socket. By delegating responsibility to select() and poll(), you don’t have to constantly check whether there is data to be read.

When should IO multiplexing be used?

There is one more Posix . 1g variations called pselect. I /O multiplexing is typically is used in networking applications in the following scenarios: When a client is handling multiple descriptors ( normally interactive input and a network socket), I/O multiplexing should be used.

What happens to client when server crashes?

When the server host crashes (which means it is not shut down by an operator), nothing is sent out on the existing network connections. We type a line of input to the client, it is written by writen (str_cli), and is sent by the client TCP as a data segment.

How does TCP server work?

TCP organizes data so that it can be transmitted between a server and a client. It guarantees the integrity of the data being communicated over a network. Before it transmits data, TCP establishes a connection between a source and its destination, which it ensures remains live until communication begins.

How do you communicate with client and server?

Sockets. Sockets facilitate communication between two processes on the same machine or different machines. They are used in a client/server framework and consist of the IP address and port number. Many application protocols use sockets for data connection and data transfer between a client and a server.

How is I / O multiplexing used in networking applications?

This capability is called I/O multiplexing and is provided by the select and poll functions, as well as a newer POSIX variation of the former, called pselect. I/O multiplexing is typically used in networking applications in the following scenarios: When a client is handling multiple descriptors (normally interactive input and a network socket)

How to use select and recvfrom for multiplexing?

We block in a call to select, waiting for the datagram socket to be readable. When select returns that the socket is readable, we then call recvfrom to copy the datagram into our application buffer. Comparing Figure 6.3 to Figure 6.1:

How does signal driven I / O work in Shichao?

We first enable the socket for signal-driven I/O ( Section 25.2) and install a signal handler using the sigaction system call. The return from this system call is immediate and our process continues; it is not blocked. When the datagram is ready to be read, the SIGIO signal is generated for our process.

Is the asynchronous I / O defined by the POSIX specification?

Asynchronous I/O is defined by the POSIX specification, and various differences in the real-time functions that appeared in the various standards which came together to form the current POSIX specification have been reconciled.