Patent ID: 7512061
Filing Date: 2009-03-31
Classification: H04L

Abstract:
1. A method comprising: detecting a crash of a first tunnel endpoint with a backup tunnel endpoint of the first tunnel endpoint; sending a hello message to a second tunnel endpoint from the backup tunnel endpoint, wherein state variables in the hello message are set as current first and second state variables of the backup tunnel endpoint; receiving a response message from the second tunnel endpoint, wherein state variables in the response message comprise first and second state variables of the second tunnel endpoint; setting the second state variable of the backup tunnel endpoint as the first state variable in the response message incremented by one; recovering the first state variable of the first tunnel endpoint when the second state variable in the response message equals the first state variable of the backup tunnel endpoint incremented by one; initiating a new session between the backup tunnel endpoint and the second tunnel endpoint; sending a session initiation request message from the backup tunnel endpoint to the second tunnel endpoint, wherein state variables in the session initiation request message are set as current first and second state variables of the backup tunnel endpoint; receiving a session initiation response message from the second tunnel endpoint, wherein the state variables in the session initiation response message comprise the first and second state variables of the second tunnel endpoint; recovering the second state variable of the first tunnel endpoint from the first state variable of the second tunnel endpoint present in the session initiation response message; and disconnecting the initiated session, wherein the first state variable comprises a sequence number for sent messages and the second state variable comprises a sequence number for received messages.