Apparatus and method for assigning virtual LANs to a switched network

• US 6,061,334 A
• Filed: 01/06/1997
• Issued: 05/09/2000
• Est. Priority Date: 07/30/1996
• Status: Expired due to Term

• Current Assignee: Avaya Incorporated
• Original Assignee: Lucent Technologies Networks Limited (Nokia Corporation)
• Inventors: Berlovitch, Albert, Shoua, Menachem, Shurman, Michael
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): VINCENT, DAVID ROBERT
• Application Number:
  US08/779,143
• Time in Patent Office: 1,219 Days
• Field of Search: 370/254, 370/255, 370/400, 370/401, 370/351, 370/395
• US Class Current: 370/255
• CPC Class Codes: H04L 12/46 Interconnection of networks
• CPC Class Codes: H04L 12/4608 LAN interconnection over ATM networks
• CPC Class Codes: H04L 12/467 Arrangements for supporting untagged frames, e.g. port-based VLANs
• CPC Class Codes: H04L 41/26 using dedicated tools for LAN [Local Area Network] management

Abstract

This invention discloses an apparatus for managing a switched routed network including a network configuration learning unit operative to learn a configuration of the switched routed network, a VLAN assignment unit for generating a division of the network into virtual LANs (VLANs) based on the learned configuration of the network; and a change manager operative to detect a change in the configuration of the network and to modify the division of the network into VLANs. A method for generating a division of a switched routed network into virtual LANs based on a learned configuration of the network is also disclosed.

Claims

1. Apparatus for managing a switched routed network comprising:

a network configuration learning unit learning a configuration of the switched routed network without forwarding traffic via the switched routed network, the network configuration learning unit comprising a poller polling at least one element of the switched routed network to obtain polling information regarding at least one division of the network into subnets of elements which communicate differently between themselves than with elements which do not belong to that subnet;

a VLAN assignment unit generating a division of the network into virtual LANs (VLANs) based on the output of the poller wherein at least one results of the polling information is used to generate an initial division of the network and to set up the VLANs; and

a network configuration change manager and modifier detecting a change in the configuration of the network and modifying the division of the network into VLANs.

2. Apparatus according to claim 1 wherein the configuration of the network includes physical configuration aspects and logical configuration aspects.

3. Apparatus according to claim 1 the network comprising:

a switching skeleton including at least one switching hub interconnected by a switch backbone, each switching hub including at least one port; and

a plurality of end-stations each having a unique physical address and each communicating with an individual one of the switching hubs via one of the switching hub'"'"'s ports, thereby defining a plurality of end-station to port connections, the plurality of end-stations including at least one router,

the network configuration learning unit comprising;

an end-station to port connection learning unit learning polled associations between ports and physical addresses of the end-stations communicating therewith;

a physical address-logical address association learning unit learning polled associations between logical addresses and physical addresses; and

an end-station to logical address association learning unit deriving associations between ports and logical addresses from said polled associations between ports and physical addresses of the end stations and said polled associations between logical addresses and physical addresses.

4. Apparatus according to claim 3 wherein said physical address-logical address association learning unit comprises:

a physical address scanner which scans physical addresses of at least some of said plurality of end stations; and

an active logical address finder which actively finds an associated logical address upon encountering each physical address.

5. Apparatus according to claim 4 wherein each said logical address comprises an IP network layer address and wherein the network comprises an IP network which is partitioned into a multiplicity of IP subnets and wherein each IP network layer address belongs to an individual one of said multiplicity of subnets and wherein said apparatus for learning also comprises apparatus for determining all IP subnets into which the IP network is partitioned.

6. Apparatus according to claim 4 wherein each said logical address comprises an IPX protocol network layer address and wherein the network is partitioned into a multiplicity of IPX networks and wherein each IPX protocol network layer address belongs to an individual one of said multiplicity of IPX networks and wherein said apparatus for learning also comprises apparatus for determining all IPX networks into which the IPX network is partitioned.

7. Apparatus according to claim 5 wherein said physical address-logical address association learning unit sends a multiplicity of ICMP echo request packets to each of at least some of said plurality of end stations, each echo request packet including a physical destination address and an IP network layer destination address which includes an IP broadcast address of an individual one of said multiplicity of subnets;

and wherein the echo request packet sent to an individual end station has a physical destination address which is the physical address of the individual end station.

8. Apparatus according to claim 7 wherein said physical address-logical address association learning unit comprises an ICMP echo reply packet analyzer deriving a physical address--IP address association from each arriving ICMP echo reply packet.

9. Apparatus according to claim 6 wherein said physical address-logical address association learning unit sends an IPX diagnostic packet to each of at least some of said plurality of end stations, an IPX diagnostic packet including a physical destination address and an IPX network layer destination address which includes an IPX broadcast address;

and wherein the IPX diagnostic packet sent to an individual end station comprises an IPX diagnostic packet whose physical destination address is the physical address of the individual end station.

10. Apparatus according to claim 9 wherein said physical address-logical address association learning unit comprises an IPX diagnostic packet analyzer deriving a physical address--IPX address association from each arriving IPX diagnostic reply packet.

11. Apparatus according to claim 3 wherein said physical address-logical address association learning unit includes an IP network layer address identifier passively identifying, for each physical address, a logical address comprising an IP network layer address,

and wherein said IP network layer address identifier listens for ARP packets and analyzes the ARP packets and derives therefrom IP network layer addresses.

12. Apparatus according to claim 3 wherein said network comprises an IPX network,

and wherein said plurality of end-stations comprises at least one IPX file servers and at least one NetWare clients, and wherein each of the IPX clients is served by one of the at least one IPX file servers,

and wherein said network configuration learning unit also comprises a server-client learner identifying servers and clients from among said plurality of end-stations and learning relationships between said servers and said clients.

13. Apparatus according to claim 1 the network comprising:

a switching skeleton including at least one switching hub interconnected by a switch backbone, each switching hub including at least one port; and

a plurality of end-stations each having a unique physical address and each communicating with an individual one of the switching hubs via one of the switching hub'"'"'s ports, thereby defining a plurality of end-station to port connections, the plurality of end-stations including at least one router,

the VLAN assignment unit comprising;

an end-station grouper dividing the plurality of end-stations into sets, wherein each set comprises at least one end-station; and

grouping together each first and second set from among said sets if at least one of the end-stations in the first set is associated with the same port as at least one of the end-stations in the second set, thereby to generate at least one disjoint groups; and

a VLAN allocator allocating a VLAN to each of the at least one disjoint groups characterized in that packets sent by an individual end-station connected to a port belonging to an individual VLAN, including broadcasts packets, are transmitted only to end-stations connected to one of the ports within the same VLAN.

14. A method according to claim 13 wherein the network comprises an IP network which is partitioned into a multiplicity of IP subnets and said sets respectively correspond to said IP subnets.

15. A method according to claim 13 wherein the network is partitioned into a multiplicity of IPX networks and said sets respectively correspond to said IPX networks.

16. A method according to claim 13 wherein the network comprises an IPX network and wherein said plurality of end-stations comprises at least one IPX file servers and at least one IPX clients and wherein each of the IPX clients is served by one of the at least one IPX file servers, and wherein each of said sets comprises an individual IPX file server and the IPX clients served thereby.

17. A method according to claim 16 and wherein the VLANs are allocated so as to increase the number of clients which communicate directly with their servers rather than via a router.

18. A method according to claim 13 and also comprising the step of allocating global VLANs to at least one of the ports so as to reduce the number of end-station pairs which hear broadcast packets arriving to one another.

19. A method according to claim 18 and also comprising the step of allocating global VLANs to at least one of the ports so as to minimize the number of end-station pairs which hear broadcast packets arriving to one another.

20. Apparatus according to claim 1, the network including a plurality of network elements, the change manager comprising:

an event detector detecting at least one event at an individual network element including detecting the identity of the individual end-station, the event comprising at least one of the following;

at least one logical change;

at least one physical change; and

at least one communication failure; and

an event categorizer categorizing at least one event as a problematic event or a non-problematic event and, if the event is categorized as problematic, alleviating the failure situation,

wherein said event detector also comprises;

a mismatch detector detecting a mismatch between the network address of an end-station and a VLAN to which the port to which the end-station is connected belongs; and

a VLAN identifier determining a new VLAN which matches the network addresses of all end-stations connected to said port; and

assigning the new VLAN to the port.

21. A method according to claim 20 wherein said at least one physical change comprises at least one of the following:

at least one new end-station added at at least one individual port within the network; and

at least one end-station which has moved from a first port within the network to a second port within the network.

22. A method according to claim 20 wherein said at least one logical change comprises an IP address of at least one end-station which has changed.

23. A method according to claim 20 wherein said at least one communication failure comprises at least one of:

a failed attempt of an IPX client end-station to initially connect to a server end-station; and

an IPX client end-station which has been disconnected from a server end-station.

24. A method according to claim 20 wherein said analyzing and alleviating step comprises:

detecting a mismatch between the network address of an end-station and a VLAN to which the port to which the end-station is connected belongs; and

determining a new VLAN which matches the network addresses of all end-stations connected to said port; and

assigning the new VLAN to the port.

25. A method according to claim 20 and also comprising storing a record of problematic and non-problematic events occurring at network elements.

26. A method according to claim 25 wherein said record of problematic events comprises, for each problematic event, a description of a contradictory VLAN assignment associated with the problematic event.

27. A method according to claim 26 wherein said record of problematic events comprises, for at least one problematic event, a recommendation describing how a human operator may resolve the contradictory VLAN assignment.

28. A method according to claim 26 wherein said record of problematic events comprises, for at least one problematic event, a description of a system action which resolves the contradictory VLAN assignment.

29. A method according to claim 20 wherein said step of alleviating comprises alerting a human operator that a problematic event has occurred.

30. A method according to claim 25 wherein said step of alleviating comprises alerting a human operator that a problematic event has occurred.

31. Apparatus according to claim 1 wherein each VLAN comprises a physical network allowing a particular mode of communication between only those network elements which belong to that VLAN.

32. Apparatus according to claim 1 wherein elements of each individual subnet communicate between themselves directly and communicate with elements which do not belong to said individual subnet only via a router.

33. Apparatus according to claim 2 wherein at least a portion of said switched routed network comprises an IP network and wherein said subnets of elements comprise IP subnets.