What term describes a signal sent over a network to verify that a link is alive or active?

• A. Keepalive Signal
• B. Heartbeat
• C. Ping
• D. Beacon

Answer: (A)

The idea being tested is the keepalive mechanism, a lightweight signal exchanged over a network to verify that a connection remains alive. A keepalive message is sent at regular intervals while a session is idle, and if the other end doesn’t respond within a configured timeout, the connection is considered broken and can be reopened or the session torn down. This keeps the link healthy and lets you detect silent failures without flooding the network with data.

This term is the best fit because it directly describes the ongoing, purpose-built check for liveness of a specific connection. A ping, by contrast, is a diagnostic test using ICMP to see if a host is reachable, not a continuous signal used to maintain an established session. A heartbeat is similar in spirit but is often used in broader health-monitoring of components or services rather than the persistent link-level keepalive of a single connection. A beacon tends to refer to broadcasting presence or status in a network, not to the routine liveness check of an active link.