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:
Feb. 09, 1999
Filed:
Dec. 30, 1991
Radia Joy Perlman, Acton, MA (US);
William R Hawe, Pepperell, MA (US);
John A Harper, Golfe Juan, FR;
Digital Equipment Corporation, Maynard, MA (US);
Abstract
A technique for logically connecting local area networks (LANs) that may be separated by wide area networks containing routers and other network components. A logical link is formed between two bridge-like devices called tunnelers, such that, once a tunnel has been established between two LANs, other devices on the LANs can communicate as if the tunnel were a bridge. The tunneling mechanism of the invention requires that each LAN or extended LAN have only one active tunneler at any particular time, referred to as the designated tunneler, and each of the tunnelers is configured to have knowledge of the identities of the other tunnelers. A tunnel is established after a successful exchange of messages between two tunnelers, and then traffic may be forwarded through the tunnel in a transparent manner. The tunneling mechanism permits messages to be forwarded between LANs separated by a wide area network containing routers. Moreover, the mechanism permits filtering of traffic, such that only selected types of traffic, or messages for selected destinations or from selected sources, are forwarded through tunnels. The tunneling mechanism inherently precludes the formation of closed communication loops. An alternate embodiment of the invention optimizes the configuration process for particular network topologies.