dcsimg
Main » TERM » K »

Keepalive Signal Definition and Meaning

In networking, a keepalive signal is a packet that is sent to maintain a connection between two points even though data is not being transmitted.

Transmission control protocol (TCP) is one protocol that can use keepalive packets to maintain a connection between a client (typically a computer or another end-user device) and a server so it can process multiple HTTP requests without needing to repeat the three-step handshake. The keepalive signal reduces latency issues for the client and also helps the efficiency of the broader network by conserving bandwidth that can be used elsewhere and requiring less overall maintenance for a single connection.

Keepalive signals can also be used to validate that a connection is still secure. When a client sends a keepalive signal that is not acknowledged within a designated length of time by the server (or vice-versa), it will reattempt a limited number of transmissions before terminating the connection and requiring a new three-step handshake to be initiated. This prevents packets from being received out of order, incomplete, or damaged—one of the main benefits of using TCP instead of UDP.

UDP, SMB, TLS, NAT and SIP are among the protocols that can use keepalive signals, and some persistent connections, like VPNs, can use them too. HTTP code also has a Keep-Alive function that works at the browser level, but it is unrelated to the TCP-IP function.

Keepalive signals have several different configurations:

  • The duration of time between transmissions
  • The total number of transmissions before timeout
  • The number of retransmission attempts after a packet has not been received
  • The interval between retransmissions









LATEST ARTICLES
Texting & Chat Abbreviations

From A3 to ZZZ we list 1,559 text message and online chat abbreviations to help you translate and understand today's texting lingo. Includes Top... Read More »

Huge List of Computer Certifications

Have you heard about a computer certification program but can't figure out if it's right for you? Use this handy list to help you decide. Read More »

STUDY GUIDES
Computer Architecture Study Guide

Computer architecture provides an introduction to system design basics for most computer science students. Read More »

Network Fundamentals Study Guide

Networking fundamentals teaches the building blocks of modern network design. Learn different types of networks, concepts, architecture and... Read More »

The Five Generations of Computers

Learn about each of the five generations of computers and major technology developments that have led to the computing devices that we use... Read More »