The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 19, 2002
Filed:
Nov. 02, 1998
Shawn Mamros, Arlington, MA (US);
Kerry M. Hannigan, Boston, MA (US);
Nortel Networks Limited, St. Laurent, CA;
Abstract
A method and apparatus for determining the reachability of a remote computer from a local computer through a secured communications link through the Internet. In one embodiment, the secured ISAKMP/Oakley communications link is established between a remote computer and a local computer through the Internet. A protected keepalive message is transmitted by the local computer to the remote computer in the event that the communications link has been idle for a period of time. The protected keepalive message is not a re-key request by the local computer to renegotiate the policy/key(s) of the secured communications link to the Internet. In one embodiment, the protected keepalive message is a protected ISAKMP/Oakley command to which a protected acknowledgement must be supplied. If a protected acknowledgement is received from the remote box by the local box in response to the protected keepalive message, then it is assumed that the remote box is still reachable. However, if the protected acknowledgement is not received from the remote box in response to the protected keepalive message, then it is assumed that their remote box is no longer reachable. In this case, the secured communications link between the remote box and the local box is terminated by the local box.