This configuration parameter specifies how many consecutive keepalive probe intervals must pass without receiving a response before a Cisco HDLC (High-Level Data Link Control) point-to-point link is declared down and the connection is terminated. For example, if keepalive interval is 10 seconds and downCount is 5, the link fails after 50 seconds of no response. Both endpoints of the HDLC link should be configured with matching values to ensure consistent link failure detection and prevent asymmetric failover behavior.