Optimizing flow detection and reducing control plane processing in a multi-protocol over ATM (MPOA) system

• US 6,279,035 B1
• Filed: 04/10/1998
• Issued: 08/21/2001
• Est. Priority Date: 04/10/1998
• Status: Expired due to Term

• Current Assignee: RPX Clearinghouse LLC (RPX Corporation)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Pitcher, Derek H., Mangin, James, Haney, Jeanne, Brown, Brian, Seshadri, Kishore K.
• Primary Examiner(s): Sheikh, Ayaz
• Assistant Examiner(s): DINH, KHANH Q
• Application Number:
  US09/058,693
• Time in Patent Office: 1,229 Days
• Field of Search: 370/401, 370/412, 370/230, 709/224, 709/228, 709/245
• US Class Current: 709/224
• CPC Class Codes: H04L 2012/5617 Virtual LANs; Emulation of LANs
• CPC Class Codes: H04L 2012/5667 IP over ATM
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

A method and apparatus for reducing the amount of control plane processing and flow detection required in a Multiprotocol Over ATM (MPOA) system are provided. According to one aspect of the present invention, flow detection processing may be altered based upon a packet'"'"'s content. A first MPOA client (MPC) may include a plurality of flow detection mechanisms including standard MPOA processing and modified flow detection processing. For example, a flow may be determined to exist when the number of packets to a particular destination within a predetermined time interval exceeds a threshold value. Alternatively, a flow may be determined to exist immediately for certain types of traffic and detection of a flow may be suppressed for other types of traffic. Upon receipt at a first MPC, traffic may be classified based upon any information contained within a packet, including the header, the payload, or portions and/or combinations thereof. Based upon the packet'"'"'s content, the MPC then selects among the plurality of flow detection mechanisms for purposes of determining whether or not a flow exists. According to another aspect of the present invention, control plane processing may be managed based upon a packet'"'"'s content. A first MPC determines whether or not a stream of data with which a packet is associated justifies establishing a shortcut between the first MPC and the MPC with which the target is associated. After determining that the shortcut is justified, the first MPC allows or disallows the transmission of a resolution request based upon the packet'"'"'s content.

Claims

1. A method comprising:

receiving a packet at a first Multi-protocol Over ATM (MPOA) client (MPC), the packet destined for a host which is associated with a second MPC;

selecting among a plurality of flow detection mechanisms based upon the packet'"'"'s content to accomplish flow threshold detection before a virtual channel connection (VCC) is established, the plurality of flow detection mechanisms including standard MPOA processing and modified flow detection processing for delaying, by passing, or accelerating flow threshold detection; and

performing flow threshold detection processing to determine whether or not the packet justifies establishing a virtual channel connection (VCC) between the first MPC and the second MPC.

2. The method of claim 1, wherein the standard MPOA processing comprises flow threshold detection as described in Multi-Protocol Over ATM Version 1.0.

3. The method of claim 2, wherein the modified flow detection processing includes bypassing the flow threshold detection.

4. A method comprising:

receiving a packet at a first Multi-protocol Over ATM (MPOA) client (MPC), the packet destined for a host which is associated with a second MPC;

selecting among a plurality of flow detection mechanisms based upon the packet'"'"'s content to accomplish flow threshold detection before a virtual channel connection (VCC) is established, the plurality of flow detection mechanisms including standard MPOA processing and modified flow detection processing for delaying, bypassing, or accelerating flow threshold detection;

performing flow threshold detection processing to determine whether or not a stream of data with which the packet is associated justifies establishing a virtual channel connection (VCC) between the first MPC and the second MPC; and

after determining that establishing the VCC is justified, allowing or disallowing the transmission of a resolution request based upon the packet'"'"'s content.

5. The method of claim 4, wherein allowing or disallowing the transmission of a resolution request is based upon an internetwork address in the packet.

6. The method of claim 4, wherein allowing or disallowing the transmission of a resolution request is based upon a subnet with which the packet is associated.

7. The method of claim 6, wherein the subnet comprises a destination Internet Protocol (IP) subnet address.

8. The method of claim 6, wherein the subnet comprises a source Internet Protocol (IP) subnet address.

9. The method of claim 6, wherein the subnet comprises a destination Internetwork Packet Exchange (IPX) address.

10. The method claim 6, wherein the subnet comprises a source Internetwork Packet Exchange (IPX) address.

11. The method of claim 4, wherein allowing or disallowing the transmission of a resolution request is based upon a media access control (MAC) address associated with the packet.

12. The method of claim 11, wherein the MAC address is a source MAC address.

13. The method of claim 11, wherein the MAC address is a destination MAC address.

35. The method of claim 5, wherein the internetwork address comprises a destination Internetwork Packet Exchange (IPX) address.

36. The method of claim 5, wherein the internetwork address comprises a source Internetwork Package Exchange (IPX) address.

14. A method of reducing control plane processing in a Multiprotocol Over ATM (MPOA) system, the method comprising:

receiving a packet at a first MPOA client (MPC), the packet destined for a host which is associated with a second MPC;

selecting among a plurality of flow detection mechanisms based upon the packet'"'"'s content to accomplish flow threshold detection before a virtual channel connection (VCC) is established, the plurality of flow detection mechanisms including standard MPOA processing and modified flow detection processing for delaying, bypassing, or accelerating flow threshold detection;

performing flow threshold detection processing to determine whether or not the packet justifies resolving a shortcut and establishing a virtual channel connection (VCC) between the first MPC and the second MPC; and

after performing flow threshold detection processing and determining that the VCC is justified, suppressing a resolution request for an identified flow based upon the packet'"'"'s content.

15. The method of claim 14, wherein a device upon which the first MPC resides includes a verification table, and the method further comprises:

determining whether of not to suppress the resolution request by comparing the packet'"'"'s content to one or more entries from the verification table; and

suppressing the resolution request if the identified flow corresponds to an entry of the one or more entries.

16. The method of claim 14, wherein a device upon which the first MPC resides includes a verification table, and the method further comprises:

determining whether of not to suppress the resolution request by comparing the packet'"'"'s content to entries from the verification table; and

suppressing the resolution request if the identified flow does not correspond to an entry of the verification table.

17. A packet forwarding device comprising:

a plurality of ports; and

an address resolution unit coupled to the plurality of ports to receive packets, to select among a plurality of flow detection mechanisms based upon the packet'"'"'s content to accomplish flow threshold detection before a virtual channel connection (VCC) is established, and to perform flow threshold detection processing including examining a packet to determine whether establishing a virtual channel connection (VCC) between a first MPOA client (MPC) and a second MPC is justified, where existence of a flow is determined by a flow detection mechanism of the plurality of flow detection mechanisms which operates in a plurality of modes based upon the packet'"'"'s content to accomplish flow threshold detection, the plurality of modes including a first flow detection mode and a second flow detection mode, the first flow detection mode corresponding to a standard MPOA processing procedure and the second flow detection mode corresponding to a modified flow detection procedure, the modified flow detection procedure for delaying, bypassing, or accelerating flow threshold detection.

18. The packet forwarding device of claim 17, wherein the address resolution unit comprises a processor.

19. The packet forwarding device of claim 17, wherein the address resolution unit comprises an application specific integrated circuit (ASIC).

20. The packet forwarding device of claim 17, wherein the address resolution unit comprises programmable logic.

21. The packet forwarding device of claim 17, wherein the shortcut includes a first protocol entity at a first end and a second protocol entity at a second end.

22. The packet forwarding device of claim 21, wherein the first protocol entity comprises an ingress Multi-protocol Over ATM (MPOA) client (I-MPC) and the second protocol entity comprises an egress MPOA client (E-MPC).

23. The packet forwarding device of claim 17, wherein the first flow detection mode operates in accordance with flow threshold detection described in Multi-Protocol Over ATM Version 1.0.

24. The packet forwarding device of claim 17, wherein the second flow detection mode bypasses flow threshold detection.

25. The packet forwarding device of claim 17, wherein the second flow detection mode suppresses resolution requests for a subset of flows identified by the first flow detection mode.

26. A packet forwarding device comprising:

a storage device having stored therein a flow threshold detection routine for detecting a flow between a first Multi-protocol Over ATM (MPOA) client (MPC) and a second MPC in an MPOA system;

a processor coupled to the storage device for selecting among a plurality of flow detection mechanisms based upon the packet'"'"'s content to accomplish flow threshold detection before a virtual channel connection (VCC) is established, executing the flow threshold detection routine to perform flow threshold detection processing including examining a packet to determine whether establishing a virtual channel connection (VCC) between the first MPC and the second MPC is justified, where existence of a flow is determined by one of the plurality of flow detection mechanisms to accomplish flow threshold detection, the plurality of flow detection mechanisms including standard MPOA processing and modified flow section processing, the modified flow detection processing for delaying, bypassing, or accelerating flow threshold detection.

27. The packet forwarding device of claim 26, wherein the standard MPOA processing comprises flow threshold detection as described in Multi-Protocol Over ATM Version 1.0.

28. The packet forwarding device of claim 27, wherein the modified flow detection processing bypasses the flow threshold detection.

29. The packet forwarding device of claim 27, wherein the modified flow detection processing suppresses resolution requests for a subset of flows identified by the flow threshold detection.

30. The packet forwarding device of claim 29, wherein the storage device includes a verification table, and the modified flow detection processing suppresses resolution requests for those of the flows identified by the flow threshold detection that correspond to an entry of the verification table.

31. The packet forwarding device of claim 29, wherein the storage device includes a verification table, and the modified flow detection processing suppresses resolution requests for those of the flows identified by the flow threshold detection that do not correspond to an entry of the verification table.

32. A method of reducing flow detection processing in a Multiprotocol Over ATM (MPOA) system, the method comprising:

a first MPOA client (MPC) receiving a packet destined for a host which is associated with a second MPC, the first MPC configured to select among a plurality of flow detection mechanisms based upon the packet'"'"'s content to accomplish flow threshold detection before a virtual channel connection (VCC) is established and to perform one or more tests to determine whether or not the packet establishes a flow between the first MPC and the second MPC;

the first MPC performing a first test based on the packet'"'"'s contents, the first test indicating whether or not to perform flow detection processing for the packet;

if flow detection processing is to be performed, then performing flow threshold detection processing to determine whether or not the packet justifies establishing a virtual channel connection (VCC) including performing a second test by updating a count associated with the host, and comparing the count to a predetermined threshold; and

otherwise, bypassing the second test to avoid unnecessary flow detection processing;

if the predetermined threshold has been achieved, the first MPC subsequently determining whether or not the packet meets one or more predetermined criteria; and

establishing a shortcut virtual channel connection (VCC) from the first MPC to the second MPC if it was determined that both the predetermined threshold has been achieved, and the packet meets the one or more predetermined criteria.

33. The method of claim 32, wherein the first MPC and the second MPC are co-located.

34. The method of claim 32, wherein the first MPC and the second MPC reside on separate devices.