Method and apparatus for transparently bridging traffic across wide area networks
First Claim
1. A method for logically connecting local area networks (LANS) interconnected by network components that include bridges, the method comprising the steps of:
- selecting bridges to provide a plurality of tunnels between LANs that are widely separated said LANS that are widely separated being referred to as extended LANS (XLANS) and said selected bridges being referred to as tunnelers;
electing a designated tunneler for each extended LAN (XLAN) for which tunneling is to be provided, with each XLAN having no more than one designated tunneler and a single tunneler being designated by at least one XLAN;
configuring the designated tunneler by supplying the designated tunneler with information identifying other designated tunnelers;
establishing at least one tunnel between two of said XLANs through said designated tunneler and at least one of said other designated tunnelers, by exchanging messages between the designated tunneler and said at least one her designated tunneler; and
selectively forwarding message traffic through the at least one established tunnel, from one LAN to another by appending to a message a destination address that includes an address of a receiving endpoint tunneler of the tunnel, and also includes a port identifier that defines, in part, the receiving endpoint tunneler of the tunnel.
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Accused Products
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.
60 Citations
27 Claims
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1. A method for logically connecting local area networks (LANS) interconnected by network components that include bridges, the method comprising the steps of:
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selecting bridges to provide a plurality of tunnels between LANs that are widely separated said LANS that are widely separated being referred to as extended LANS (XLANS) and said selected bridges being referred to as tunnelers; electing a designated tunneler for each extended LAN (XLAN) for which tunneling is to be provided, with each XLAN having no more than one designated tunneler and a single tunneler being designated by at least one XLAN; configuring the designated tunneler by supplying the designated tunneler with information identifying other designated tunnelers; establishing at least one tunnel between two of said XLANs through said designated tunneler and at least one of said other designated tunnelers, by exchanging messages between the designated tunneler and said at least one her designated tunneler; and selectively forwarding message traffic through the at least one established tunnel, from one LAN to another by appending to a message a destination address that includes an address of a receiving endpoint tunneler of the tunnel, and also includes a port identifier that defines, in part, the receiving endpoint tunneler of the tunnel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for logically connecting local area networks (LANS) interconnected by network components that include a plurality of bridges comprising the steps of:
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selecting from said plurality of bridges selected bridges, to provide tunnels between LANs that are widely separated, said LANS that are widely separated being referred to as extended LANS (XLANS) with said widely separated LANS having routers, and said selected bridges being referred to as tunnelers; electing a unique designated tunneler for each extended LAN (XLAN) for which tunneling is to be provided, with each XLAN having no more than one designated tunneler and a single tunneler being designated by one XLAN; configuring the designated tunneler by supplying the designated tunneler with the identities of other designated tunnelers and the identities of ports through which the other tunnelers are connected to XLANs with which they are associated; establishing at least one tunnel between at least two of said designated tunnelers, by transmitting a greeting from a first designated tunneler to each other tunneler that is a potential tunnel endpoint, receiving a message from one of the potential tunnel endpoints confirming that a tunnel is established, and recording that a tunnel has been established; and selectively forwarding message traffic through the established tunnel, from one LAN to another by appending to a message a destination address that includes the address of a receiving endpoint tunneler of the tunnel, and also includes a port identifier that defines, in part, the receiving endpoint of the tunnel. - View Dependent Claims (14, 15, 16)
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17. Apparatus for logically connecting local area networks (LANs) interconnected by network components that include bridges, the apparatus comprising:
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a plurality of bridges disposed between LANs that are interconnected by routers, said LANS being widely separated, and said LANS that are widely separated being referred to as extended LANS (XLANS), said bridges being referred to as tunnelers; means, for electing a unique designated tunneler for each extended LAN (XLAN) from a corresponding one of said plurality of bridges for which tunneling is to be provided, with each XLAN having no more than one designated tunneler and a single tunneler being designated by one XLAN; means, responsive to information identifying other tunnelers, for configuring the tunnelers with which a tunnel is established; means, responsive to messages exchanged between at least two tunnelers, for establishing at least one tunnel between said at least two tunnelers; and means, contained within each tunneler, for selectively forwarding message traffic through the established tunnel, from one LAN to another by appending to a message a destination address that includes the address of a receiving endpoint tunneler of the tunnel, and also includes a sort identifier that defines, in part, the receiving endpoint of the tunnel. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification