Apparatus and method for discovering a topology for local area networks connected via transparent bridges
First Claim
1. In a bridged local area network (LAN) communication system containing a plurality of LANs communicatively coupled via a plurality of transparent bridges, wherein each LAN includes a network management module (NMM), each NMM for controlling and monitoring communications between devices on its LAN and communications in and out of its LAN, a computer implemented method of determining an active topology of said bridged LAN, said computer implemented method comprising the computer implemented steps of:
- constructing communication pathways between NMMs of said plurality of LANs, said step of constructing communication pathways operable within each transparent bridge; and
determining the active topology of said bridged LAN utilizing said communication pathways to send and receive adjacency request messages and adjacency response messages between NMMs of different LANs and wherein adjacency to a particular LAN is determined by examining said adjacency response messages from said NMMs of different LANs resultant from said adjacency request messages sent by said NMMs of different LANs.
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Accused Products
Abstract
A system of discovering the active topology of the LANs (local area networks) connected via any apparent bridges that conform to the IEEE 802.1D standard. A discovered active topology of the present invention consists of the active bridges, the LANs and the NMMs (network management modules) that constitute the bridged LAN. The system of the present invention advantageously utilizes the standard (IEEE 802.1D) defined behaviors of transparent bridges to discover the active topology. In so doing, the present invention does not require the bridges to issue any special proprietary frames for development of the active topology. The IEEE 802.1D conforming bridges have the property of forming a path between two conversing end stations. If the two end stations reside in adjacent LANs, the path between these two LANs only has the connecting bridge and no other LAN in between. The present invention utilizes this property in discovering the complete active topology of a bridged LAN via special communications between NMMs located on the LANs. Via cyclic processing and age out functions, the present invention is able to alter the active topology in response to changes within the bridged LAN.
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Citations
21 Claims
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1. In a bridged local area network (LAN) communication system containing a plurality of LANs communicatively coupled via a plurality of transparent bridges, wherein each LAN includes a network management module (NMM), each NMM for controlling and monitoring communications between devices on its LAN and communications in and out of its LAN, a computer implemented method of determining an active topology of said bridged LAN, said computer implemented method comprising the computer implemented steps of:
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constructing communication pathways between NMMs of said plurality of LANs, said step of constructing communication pathways operable within each transparent bridge; and determining the active topology of said bridged LAN utilizing said communication pathways to send and receive adjacency request messages and adjacency response messages between NMMs of different LANs and wherein adjacency to a particular LAN is determined by examining said adjacency response messages from said NMMs of different LANs resultant from said adjacency request messages sent by said NMMs of different LANs. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of determining a topology of a network, said network including a first local area network (LAN), a second LAN, and a third LAN, each of said first, second, and third LANs including one or more network management modules (NMMs), each NMM for controlling and monitoring communications between devices on its LAN and communications in and out of its LAN, said method comprising the steps of:
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(a) determining a representative first NMM, for said first LAN; (b) determining a representative second NMM for said second LAN; (c) determining a representative third NMM for said third LAN; (d) determining whether said first LAN is one hop away from said second LAN and if so, recording in an adjacency database the one hop away relationship between said first LAN and said second LAN; (e) determining whether said first LAN is one hop away from said third LAN and if so, recording in an adjacency database the one hop away relationship between said first LAN and said third LAN; and (f) determining whether said second LAN is one hop away from said third LAN and if so, recording in an adjacency database the one hop away relationship between said second LAN and said third LAN; and (g) building a topology database based upon said adjacency databases, said topology database containing a representation of the topology of the network. - View Dependent Claims (10, 11, 12)
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13. A method of determining a topology of a network, said network comprising a first transparent bridge coupling a first local area network (LAN) and a second LAN and a second transparent bridge coupling said second LAN and a third LAN, each of said first, second, and third LANs including a network management module (NMM) for controlling and monitoring communications between devices on its LAN and communications in and out of its LAN, said method comprising the steps of:
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(a) a first NMM determining that said first LAN is one hop away from said second LAN over said first transparent bridge and recording in a topology database the one hop away relationship between said first LAN and said second LAN; (b) a second determining that said second LAN is one hop away from said third LAN and recording in said topology database the one hop away relationship between said second LAN and said third LAN; and (c) building a representation of the topology of the network based upon the one hop away relationships. - View Dependent Claims (14, 15)
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16. In a bridged local area network (LAN) communication system, an improved method of determining an active topology of said bridged LAN, said bridged LAN containing a plurality of LANs communicatively coupled via a plurality of transparent bridges, wherein each LAN includes a network management module (NMM), each NMM for controlling and monitoring communications between devices on its LAN and communications in and out of its LAN, wherein a spanning tree procedure has eliminated communication loops in said bridged LAN, wherein communication pathways have been created between the NMMs of said plurality of LANs based upon filtering databases established at each of said plurality of transparent bridges as a result of the spanning tree procedure, wherein the improvement comprises the computer implemented steps of:
for each of said plurality of LANs selecting a NMM as a designated NMM for the LAN, said designated NMM identifying those of said plurality of LANs that are adjacent to the LAN, said designated NMM storing adjacency information in an adjacency database, said adjacency information resulting from said step of identifying those of said plurality of LANs that are adjacent to the LAN, said designated NMM multicasting said adjacency information to other NMMs, said designated NMM receiving the multicast adjacency information sent by other NMMs, and said designated NMM determining the active topology based upon the multicast adjacency information. - View Dependent Claims (17, 18, 19, 20, 21)
Specification