Bridged network stations location revision

• US 6,721,275 B1
• Filed: 02/01/2000
• Issued: 04/13/2004
• Est. Priority Date: 05/03/1999
• Status: Expired due to Fees

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Rodeheffer, Thomas L., Lillibridge, Mark D., Anderson, Darrell, Thekkath, Chandramohan A., Stata, Raymond P.
• Primary Examiner(s): HSU, ALPUS
• Application Number:
  US09/494,858
• Time in Patent Office: 1,533 Days
• Field of Search: 370/229, 370/231, 370/235, 370/238, 370/254, 370/255, 370/256, 370/389, 370/400, 370/401, 370/412, 370/428, 370/463, 370/465, 709/220, 709/223, 709/230, 709/238, 709/241, 709/249, 709/250
• US Class Current: 370/238
• CPC Class Codes: H04L 12/462 LAN interconnection over a bridge based backbone
• CPC Class Codes: H04L 45/04 Interdomain routing, e.g. hierarchical routing
• CPC Class Codes: H04L 45/122 by minimising distances, e.g. by selecting a route with minimum of number of hops
• CPC Class Codes: H04L 45/32 Flooding denial of service attacks H04L63/1458
• CPC Class Codes: H04L 45/48 Routing tree calculation

Abstract

Managing end stations locations in a bridged network includes providing a smart bridge, and performing communications operations using a network flood active port connections table, a network flood reaching table, a best path forwarding table and a best path sourcing table. An end station locations revision manages a host location (HLOC) table. End stations locations revision is invoked upon detection of changes in any end station location. The end stations locations revision exchanges location revision grandparent (LRG), a location revision child (LRC) table and a location revision wavefront distribution protocol. The locations revision passes the location revision request from the smart bridge over a topology of the bridged network. A location revision wavefront starts at the root and, spreads a location revision request for revising the HLOC of the other smart bridges. The wavefront spreads by wavefront protocol.

Claims

1. A method for managing end stations locations in a bridged network, comprising:

providing one or more smart bridges;

performing in each of the smart bridges an end stations locations revision which manages a host location (HLOC) table, the end stations locations revision being invoked upon detecting changes in any end station location in order to prevent different smart bridges from using different end stations locations for a same end station that changed its locations; and

wherein a location revision wavefront starts at a root of a location revision spanning tree (LRST) over a topology of the bridged network, the location revision wavefront, in cooperation with other smart bridges in the bridged network, spreading to the other smart bridges a location revision wavefront for revising the HLOC of each of the other smart bridges.

2. The method of claim 1, further comprising:

performing in each of the smart bridges communications operation using a network flood active port connections (NFA) table, a network flood reaching (NFR) table, a best path forwarding (BPF) table and a best path sourcing (BPS) table, the communications operation invoking the end stations locations revision upon detecting the changes in any end station location.

3. The method of claim 1, wherein the HLOC table includes entries accessed by an index, each entry having host address and segment fields.

4. The method of claim 3, wherein the host address is an identifier of the host including a 48-bit Ethernet address.

5. The method of claim 3, wherein each HLOC table entry further includes a “

valid”

bit indicating valid and invalid host address.

6. The method of claim 3, wherein each segment field indicates the segment on which a given host address is located.

7. The method of claim 1, wherein the end stations locations revision passes a location revision request from a smart bridge via a location revision grandparent (LRG) of the smart bridge up along a location revision spanning tree (LRST) until a root of the LRST is reached unless the smart bridge is the root of the LRST, the location revision request passing from one respective LRG to a next respective LRG until the root is reached.

8. The method of claim 1, wherein the location revision wavefront spreads through the bridged network by means of a wavefront protocol which governs bridge-to-bridge exchange of location revision request packets.

9. The method of claim 1, wherein the root assigns a serial number including an index number to each location revision wavefront the root originates so that each smart bridge forwards the location revision request together with the serial number in order to indicate whether the location revision request pertains to a new or old location revision wavefront.

10. The method of claim 9, wherein the end station location revision uses a location revision wavefront (LRW) queue for managing location revision wavefronts, the index number being used for accessing the LRW queue.

11. The method of claim 1, wherein the end stations locations revision uses a location revision wavefront (LRW) queue for managing location revision wavefronts.

12. The method of claim 11, wherein the LRW queue is a finite circular buffer arranged to function as a queue whose entries are indexed so that only entries which correlate to index numbers between old (LROLD) and new (LRNEW) need to be considered.

13. The method of claim 12, wherein any one of the smart bridges that receives the location revision wavefront packet determines a neighbor bridge that sent the location revision wavefront packet from the source address or from a node index associated with the neighbor bridge if the node index is included in the location revision wavefront packet.

14. The method of claim 1, wherein receipt of a location revision wavefront packet prompts the start of the end stations locations revision in which the location revision wavefront packet provides a wavefront index, a HLOC table index, a host address, identification of the segment to which the host is attached and the source address of the packet.

15. The method of claim 14, wherein, if the wavefront index equals a new wavefront index number (LRNEW), the end stations locations revision revises an entry of the HLOC pointed by the HLOC table index with the host address and segment identification.

16. The method of claim 14, wherein the end stations locations revision sends an acknowledgment to a neighbor bridge that sent the location revision wavefront packet if the wavefront index is less than LRNEW.

17. A method for managing end stations locations in a bridged network, comprising:

providing one or more smart bridges;

performing in each of the smart bridges an end stations locations revision which manages a host location (HLOC) table he end stations locations revision being invoked upon detecting changes in any end station location in order to prevent different smart bridges from using different end stations locations for a same end station that changed its location; and

wherein the end stations locations revision in any of the smart bridges exchanges location revision packets with other smart bridges in the bridged network according to a respective location revision grandparent (LRG), a respective location revision child (LRC) table and a location revision wavefront distribution protocol.

18. A method for managing end stations locations in a bridged network, comprising:

providing one or more smart bridges;

performing in each of the smart bridges an end stations locations revision which manages a host location (LOC) table, the end stations locations revision being invoked upon detecting changes in any end station location in order to prevent different smart bridges from using different end stations locations for a same end station that changed its location; and

wherein a location revision wavefront starts at a root of a location revision spanning tree (LRST) over a topology of the bridged network, for any location revision wavefront each of the smart bridges being ahead, on or behind the location revision wavefront.

19. The method of claim 18, wherein any one of the smart bridges is ahead of the location revision wavefront as long as the smart bridge did not yet receive a location revision wavefront packet pertaining to said location revision wavefront, the smart bridge being on the location revision wavefront upon receiving a first location revision wavefront packet pertaining to said location revision wavefront, the smart bridge being behind the location revision wavefront when it receives an acknowledgment to its location revision wavefront packet pertaining to said location revision wavefront from all its neighbor bridges.

20. The method of claim 18, wherein the location revision wavefront provides a barrier between smart bridges that are ahead of the location revision wavefront which continue to use old end stations locations and smart bridges that are behind the location revision wavefront which use new end stations locations.

21. A bridged network, comprising

one or more smart bridges configured to manage end stations locations in a bridged network, each of the smart bridges comprising:

a location revision module configured to exchange location rein packets with other bridges according to a location revision grandfather (LRG), a location revision child (LRC) table and a location revision wavefront distribution protocol, the location revision module inserting new host location information into a host location (HLOC) table; and

a communications operation module configured to check and forward packets;

the communications operation module invoking the location revision module to update host locations upon detecting a change in the host locations.

22. The bridged network of claim 21, wherein the communications operation module uses a network flood active port connections (NFA) table, a network flood reaching (NFR) table, a best path forwarding (BPE) table and a best path sourcing (BPS) table.

23. The bridged network of claim 21, wherein the smart bridge further comprises a data channel and a port, the location revision module exchanging location revision packets with other bridges via the data channel and through the port.