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:
Aug. 10, 2004
Filed:
Apr. 14, 2000
Edward Glen Britton, Chapel Hill, NC (US);
Jeffrey Douglas Haggar, Holly Springs, NC (US);
Thomas Donald Moore, Raleigh, NC (US);
Andrew Henry Richter, Raleigh, NC (US);
Barton Clark Vashaw, Apex, NC (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
The invention ensures that a single and consistent reply is made to ARP request in a system of connected IP networks. When an adapter (A) becomes active, the owning host sends an ARP advertisement into the network over the adapter. If the advertisement is also received at the sending host over a different adapter B, then the host knows that adapter B is on in the same physical network as adapter A and B can be designated as a backup adapter for A and A can be designated as backup adapter for B. If adapter A fails or becomes inactive, the host resets the backup adapter field for any adapter it owns for which A is marked as the backup adapter. If a backup adapter B has been designated for A, the host also sends an ARP advertisement associating MAC-B with IP-A. This allows network connections originally served via adapter A to continue non-disruptively over adapter B and it also provides access to the host for subsequent new connections. When adapter A becomes active again, the host sends a gratuitous ARP advertisement that maps IP-A to MAC-A. This allows adapter A to re-assume responsibility for responding to ARP requests for IP-A.