US Patent 7561593 Frame relay accelerated local management interface status-inquiry messages

A link restoration mechanism includes sending status-inquiry messages at a varying rate between two devices. Under normal operating conditions, keep-alive messages are sent from one device to another to determine the status of the communication link. The keep-alive messages are sent periodically to achieve an on-going status of the communication link between the two devices. If a pre-determined percentage of keep-alive messages fail to be received or are invalid, the communication link is declared down, that is, not functioning correctly, and data exchanges between the two devices cease. Whenever the communication link is suspected to be down due to a disruption in the sending of keep-alive messages, keep-alive messages are sent at an accelerated rate. Thus, after a pre-determined number of valid responses are received the communication link can be declared functioning normally and data exchanges between the two devices can continue.