Method of MPOA status change notification

• US 6,643,289 B1
• Filed: 12/29/1999
• Issued: 11/04/2003
• Est. Priority Date: 12/29/1999
• Status: Expired due to Fees

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: 3Com Corporation (HP Inc.)
• Inventors: Natanson, Sarit Shani, Katzri, Lior, Gershon, Benny, Aizicovich, Ronit
• Primary Examiner(s): Kizou, Hassan
• Assistant Examiner(s): Levitan, Dmitry
• Application Number:
  US09/474,687
• Time in Patent Office: 1,406 Days
• Field of Search: 370/216, 370/235, 370/351, 370/395.2, 370/395.31, 370/395.51, 370/395.52, 370/395.53, 370/411, 709/222, 709/223, 709/230
• US Class Current: 370/395.2
• CPC Class Codes: H04L 12/4608 LAN interconnection over ATM networks

Abstract

A method of notification and handling of device status changes in MPOA enabled ATM based networks. In a first method notification of changes in device status configuration are provided by selectively releasing one or more Data Direct VCs that were previously established be LECs connecting MPOA Servers and MPOA Clients. An MPOA Server, upon detecting a change to its device configuration status, releases the Data Direct VCs connecting its associated LEC to known MPSs and MPCs that are neighbors to it. All MPOA devices for which a Data Direct VC was released delete all LE_ARP cache entries associated with the ATM destination of the released Data Direct VC. In a second method, each MPOA device periodically sends keep alive messages as targetless LE_ARP messages having a time to live TLV appended. An MPOA device receiving the keep alive message, refreshes (i.e., restarts) a validation timer for each association made by the corresponding MPOA identification TLV. If the validation timer expires before being refreshed, the MPOA device deletes all associations previously made by the corresponding MPOA identification TLV.

Claims

1. In an Asynchronous Transfer Mode (ATM) based Multiple Protocol Over ATM (MPOA) network running LAN Emulation (LE), a method of notifying devices in said network of changes in device configuration status, said method comprising the steps of:

providing an MPOA device type TLV table for storing device type, Media Access Control (MAC) and control ATM address data;

providing an LE_ARP cache table for storing LEC ATM to MAC address mappings;

detecting changes in device status configuration in an MPOA device;

if changes in said device status are detected and if said MPOA device comprises an MPOA Server, releasing all LE Data Direct VCs (DDVCs) to all LAN Emulation Client (LEC) ATM addresses associated with known MPOA Server and MPOA Client neighbors;

if changes in said device status are detected and if said MPOA device comprises an MPOA Client, releasing all LE Data Direct VCs (DDVCs) to all LEC ATM addresses associated with known MPOA Server neighbors; and

deleting all entries in said MPOA device type TLV table and said LE_ARP cache table associated with LEC ATM destination addresses of released DDVCs in an MPOA device for which a DDVC was released.

2. The method according to claim 1, wherein said step of detecting comprises the step of detecting the starting of an MPOA Server.

4. The method according to claim 1, wherein said step of detecting comprises the step of detecting the starting of an MPOA Client.

5. The method according to claim 1, wherein said step of detecting comprises the step of detecting the stopping of an MPOA Client.

6. The method according to claim 1, wherein said step of detecting comprises the step of detecting the starting of a LEC associated with an MPOA device.

7. The method according to claim 1, wherein said step of detecting comprises the step of detecting the stopping of a LEC associated with an MPOA device.

8. The method according to claim 1, wherein said step of detecting comprises the step of detecting the association of a LEC with an MPOA device.

9. The method according to claim 1, wherein said step of detecting comprises the step of detecting the de-association of a LEC with an MPOA device.

10. The method according to claim 1, wherein said MPOA device type TLV table and said LE_ARP cache table comprises a combined table holding the contents of an LE_ARP cache table and an MPOA Device Type TLV table.

3. The method according to clam 1, wherein said step of detecting comprises the step of detecting the stopping of an MPOA Server.

11. In an Asynchronous Transfer Mode (ATM) based Multiple Protocol Over ATM (MPOA) network running LAN Emulation (LE), a method of notifying devices in said network of changes in device configuration status, said method comprising the steps of:

associating a validation time-out field with each MPOA device type TLV associated with a LAN Emulation Client (LEC) ATM address and registered within each MPOA device;

periodically sending a keep alive message to neighboring MPOA devices;

receiving said keep alive message by an MPOA Server or Client and in response thereto, restarting a validation timer corresponding to a validation time-out field associated with a registered MPOA device type TLV; and

deleting an MPOA device type TLV entry corresponding to a LEC ATM address whose validation timer expires before a refresh of said validation timer is received.

12. The method according to claim 11, wherein said step of periodically sending said keep alive message comprises the step of periodically sending said keep alive messages every T₁ seconds.

13. The method according to claim 12, wherein T₁ is within the range of 1 to 600 seconds.

14. The method according to claim 11, wherein said keep alive message comprises a targetless LE_ARP message having a standard MPOA Type, Length, Value (TLV) and an MPOA-VALID TLV specifying the value T₂ of said validation time-out field.

15. The method according to claim 11, wherein said keep alive message comprises a targetless LE_ARP message having a standard MPOA Type, Length, Value (TLV) and an MPOA-VALID TLV specifying the value T₂ of said validation time-out field whereby T₂ is given by T₂=N₁×

T₁, whereby T₁ is represents the time between the sending of said keep alive messages and N₁ is a positive integer.

16. The method according to claim 15, wherein N₁ is a positive integer between 1 and 10.

17. The method according to claim 11, wherein said MPOA Device Type TLV entries are stored in an MPOA device type TLV table.

18. The method according to claim 11, wherein said MPOA Device Type TLV entries are stored in an LE_ARP cache table adapted to hold said MPOA Device Type TLV entries.

19. The method according to claim 11, further comprising the step of processing a keep alive message comprising a targetless LE_ARP message containing an MPOA-VALID TLV without a validation time-out field in accordance with the ATM Forum MPOA standard.