Apparatus and method for discovering a topology for local area networks connected via transparent bridges

Claim 2

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.

Claim 3

The method of claim 1 wherein said step of determining the active topology of said bridged LAN is operable within each NMM and further comprises the computer implemented steps of: a first communication step of communicating an adjacency request message from a sender NMM to a receiver NMM over said communication pathways; a second communication step of receiving adjacency response messages communicated by said NMMs of said bridged LAN to said sender NMM as a result of said adjacency request message, said adjacency response messages communicated over said communication pathways; determining if said receiver NMM is adjacent to said sender NMM if only one adjacency response message is received by said second communication step; and repeating the above steps for a different receiver NMM until an adjacency request message is sent to each NMM of said bridged LAN.

Claim 4

The method of claim 1 wherein said step of constructing is implemented according to a spanning tree procedure.

Claim 5

The method of claim 3 wherein said spanning tree procedure is approximate to IEEE 802.1D specification standard.

Claim 6

The method of claim 1 wherein said step of determining the active topology further comprises the computer implemented step of determining that different receiver NMMs are adjacent to said sender NMM if sets of adjacent response messages received during said second communication step are consistent and are resultant from adjacency request messages sent by said sender NMM to each of said different receiver NMMs associated with a multiported bridge.

Claim 7

The method of claim 1 wherein said step of determining the active topology further comprises the computer implemented steps of: identifying an associated LAN for each receiver NMM determined to be adjacent and for each sender NMM; compiling an adjacency database for each sender NMM, said adjacency database for recording the associated LAN for each adjacent receiver NMM to each sender NMM; and multicasting said adjacency database over said bridged LAN to all other NMMs of said bridged LAN.

Claim 8

The method of claim 6 further comprising the computer implemented steps of: compiling an active topology database by collecting and compiling each adjacency database multicasted onto said bridged LAN by each sender NMM; and displaying a diagrammatic representation of said active topology of said bridged LAN by reading said active topology database and coupling LANs indicated as adjacent by said active topology database.

Claim 9

The method of claim 6 further comprising the computer implemented step of initiating each NMM within a communication pathway between said sender NMM and said receiver NMM to generate an echo response message as a result of said adjacency request message sent to said receiver NMM.

Claim 12

The method as recited by claim 9 wherein said step (d) of determining whether said first LAN is one hop away from said second LAN is carried out by determining if messages communicated from said first LAN to devices on said second LAN are transmitted to said third LAN.

Claim 13

The method as recited by claim 9 wherein the step (d) of determining whether said first LAN is one hop away from said second LAN is performed by said representative first NMM and if said first LAN is one hop away from said second LAN, a message is transmitted to a network management station (NMS), said network management station recording the one hop away relationship between said first LAN and said second LAN in a topology database.

Claim 14

The method of claim 9 further comprising the step of displaying a graphical representation of the topology of the network on a display.

Claim 17

The method as recited by claim 13 wherein said step (a) of a first NMM determining that said first LAN is one hop away from said second LAN is carried out by determining if messages communicated from said first LAN to devices on said second LAN are transmitted to said third LAN.

Claim 18

The method of claim 13 further comprising the step of displaying a graphical representation of said topology on a display.

Claim 19

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.

Claim 20

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.

Claim 21

The method of claim 16 wherein each of said plurality of LANs includes one or more NMMs, wherein said step of selecting a NMM as a designated NMM further comprises the steps of: each of said one or more NMMs multicasting an identifier onto the LAN; and identifying the NMM of said one or more NMMs with the highest priority identifier.

Claim 22

The method of claim 17 wherein said identifier includes a media access control (MAC) address.

Claim 23

The method of claim 16 further comprising the step of said designated NMM identifying itself to the other NMMs of the plurality of LANs by multicasting a media access control (MAC) address and a LAN ID.

Claim 24

The method of claim 16 wherein said step of said designated NMM identifying those of said plurality of LANs that are adjacent to the LAN further comprises the steps of: said designated NMM sending an adjacency request to the other designated NMMs of said plurality of LANs; in response to said adjacency requests said designated NMM receiving adjacency responses from the other designated NMMs; in response to said adjacency requests said designated NMM receiving echo responses from those of the other designated NMMs that hear the adjacency requests yet are not intended recipients of said adjacency requests; and based upon said echo responses and said adjacency responses, said designated NMM determining which of said plurality of LANs are adjacent to the LAN.

Claim 25

The method of claim 16 wherein a network management station (NMS) is coupled to said bridged LAN, said method further comprising the steps of: said NMS requesting the active topology from one of the plurality of designated NMMs; and after receiving the active topology, said NMS constructing a graphical representation of said active topology on a display device.