backlog refinement

To understand the backlog argument, we must realize, a given listening socket, the kernel maintains the queues:To understand the meaning of the backlog parameter, we must understand that for a listening socket,kernel maintainer two queues:1.An Incomplete connection queue, which contains an entry for each SYN that have arrived from a client for which the server Is awaiting completion of the TCP Three-way han

In Linux network programming, using the Listen function to listen to sockets, the use of Man in Linux, the 2nd parameter is explained as follows: The backlog argument defines the maximum length to which the queue of pending connections for SOCKFD may grow. If a connection request arrives when the queue was full and the client may receive a error with an indication of Econnrefus ED or, if the underlying protocol supports retransmission, the re

The maximum queue length of the input connection indication (for connection requests) is set to the backlog parameter. If the queue is full, the connection is rejected.Note:1. The backlog parameter must be a positive value greater than 0. If the passed value is equal to or less than 0, it is assumed to be the default value.2. After testing, this queue follows the FIFO principle.3. If you place the accept fu

when the server listens, it takes a certain amount of time to process a client's connection each time, which is very short (perhaps only 1ms or less), but this time still exists. The meaning of this backlog is that while the first connection request is being processed during this time, other connection requests are waiting in the request queue, and if the queue's maximum number of waits is exceeded, the other requests are ignored or will not be proces

gives some values for the coefficients:Queue Length for different backlogThe system maintains a fixed-length connection queue for the TCP service program that is waiting for a connection request. The connection in this queue has been received by TCP (the handshake has been completed three times), but it has not been received by the application (call the Accept function)The situation of LinuxThe comments in the first article say that this is the BSD situation , which is not the case in Linux . I

In the TCP/IP protocol, backlog analysis and settings, and TCP status changes. In the TCP/IP protocol, the first section describes how to set the backlog value. What is this value? We all know that TCP requires three-way handshake when establishing a connection. But if the three-way handshake is complete, the server will handle it (accept). If not, what will happen, if the accept is not timely, the client w

After some hard work, I will summarize it.ListenParametersBacklog. PS: server environment:Ubuntu12.04. Client does not matter: IMac OS X 10.7. Let's take a look at $ man listen, which contains a passage: If the backlog argument is greater than the value in/Proc/sys/NET/CORE/somaxconn, Then itIs silently truncated to that value; the default value in this file is 128. In kernelsBefore 2.4.25, this limit was a hard coded value, somaxconn, with the

In Linux, when an app creates a socket in the listen state, it assigns two queues to the socket. SYN queue: Holds the socket in the SYN_REC state, specified by the kernel parameter tcp_max_syn_backlog. Accept queue: Stores the socket in the established state, specified by the kernel parameter Somaxconn and the application itself, such as: Redis:tcp-backlog, take the minimum value in Somaxconn and Tcp-back