Patent ID: 7969894

Claim:
A method for detecting a next-hop dead gateway, comprising: sending an Internet Protocol (IP) packet by a host to a next-hop gateway associated with the host, and wherein source and destination fields in IP header associated with the IP packet includes IP address associated with the host, and wherein protocol field associated with the IP packet includes experimentation and testing code, and wherein IP payload field associated with the IP packet includes a unique identifier that indicates an IP packet is sent to detect the next-hop dead gateway; receiving the IP packet by the host from the next-hop gateway upon reviewing a routing table and the destination field in the IP header associated with the IP packet; determining whether the IP packet is received from the next-hop gateway within a first predetermined time interval, wherein determining whether the IP packet is received from the next-hop gateway within the first predetermined time interval comprises: determining whether the protocol field and the IP payload field include the experimentation and testing code, and the unique identifier, respectively, by the host; if so, then declaring the IP packet as a packet sent to detect a next-hop dead gateway by the host; and determining whether the IP packet is received within the first predetermined time interval; if so, declaring the next-hop gateway as alive; and if not, declaring the next-hop gateway as dead.