Distributing and balancing traffic flow in a virtual gateway

• US 7,593,346 B2
• Filed: 07/31/2003
• Issued: 09/22/2009
• Est. Priority Date: 07/31/2003
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Williams, Rick L., Wilson, Ian Herbert, Denny, Mark A., McLaggan, Douglas
• Primary Examiner(s): Pham; Chi H
• Assistant Examiner(s): Faroul; Farah
• Application Number:
  US10/632,704
• Publication Number:
  US 20050025179A1
• Time in Patent Office: 2,245 Days
• Field of Search: 370/252, 370/253, 370/392, 370401-404, 370/468, 370/400, 370/230, 370/230.1, 370231-235, 370/396, 370/395.54, 370/395.3, 370/395.31
• US Class Current: 370/252
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04L 45/38 Flow based routing
• CPC Class Codes: H04L 45/586 of virtual routers
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/125 by balancing the load, e.g. traffic engineering

Abstract

The distribution of traffic flows in a load-sharing redundancy group that includes a first gateway device and a second gateway device includes assigning a first set of forwarding addresses to the first gateway device and a second set of forwarding addresses to the second gateway device. The redundancy group distributes forwarding addresses to hosts which in turn use the distributed forwarding addresses to send packets to the redundancy group. The traffic flow for each of the assigned forwarding addresses is measured and may be compared to a target traffic flow. The traffic flow is adjusted to close in on the target traffic flow. Adjustment of the traffic flow can be accomplished either by changing the existing measured traffic flow by re-assigning a forwarding address originally assigned to one gateway device to a different gateway device or by altering future distribution of forwarding addresses so that additional traffic is sent to one or more forwarding addresses having lower measured traffic. The gateway devices can be routers using virtual Media Access Control (MAC) addresses as forwarding addresses. The redundancy group may also be configured to provide failover services in the event that one of the gateway devices ceases operation.

Claims

1. A method of controlling the distribution of traffic flow in a load-sharing redundancy group comprising a set of gateway devices including a first gateway device and a second gateway device which forward packets sent from hosts, the method comprising:

assigning a first plurality of forwarding addresses to the first gateway device;

assigning a second plurality of forwarding addresses to the second gateway device;

measuring the traffic flow for each of the assigned forwarding addresses; and

adjusting the traffic flow by changing allocation of the forwarding addresses based upon the measured traffic flow;

wherein the load-sharing redundancy group provides failover services in the event that one of the gateway devices ceases operation;

wherein the first gateway device actively forwards packets addressed to the first plurality of forwarding addresses and the second gateway device actively forwards packets addressed to the second plurality of forwarding addresses.

2. The method of claim 1 wherein each forwarding address is a Media Access Control (MAC) address.

3. The method of claim 2 wherein each MAC address is a virtual Media Access Control (vMAC) address.

4. The method of claim 1 wherein adjusting the traffic flow comprises altering the distribution of forwarding addresses to hosts.

5. The method of claim 4 wherein altering the distribution of forwarding addresses to hosts comprises sending a reply in response to an Address Resolution Protocol (ARP) inquiry from at least one of the hosts, the reply instructing the at least one of the hosts to use a forwarding address having the lowest measured traffic flow on one of the set of gateway devices, the one of the set of gateway devices having the lowest measured traffic flow, wherein the forwarding address is one of the first plurality of forwarding addresses or one of the second plurality of forwarding addresses.

6. The method of claim 1 wherein adjusting the traffic flow comprises re-assigning a forwarding address to a different gateway device.

7. The method of claim 1 wherein the first gateway device is a first router and the second gateway device is a second router.

8. The method of claim 1, further comprising:

comparing the measured traffic flow to a target traffic flow;

wherein the target traffic flow is equal distribution of traffic across the first gateway device and the second gateway device and further wherein adjusting the traffic flow comprises adjusting the traffic flow across the first gateway device and the second gateway device to more equally distribute the measured traffic flow between the first gateway device and the second gateway device.

9. The method as recited in claim 1, further comprising:

identifying one of the set of gateway devices having the lowest traffic flow; and

identifying a forwarding address associated with the identified gateway device, wherein the identified forwarding address has the lowest measured traffic flow of all forwarding addresses associated with the identified gateway device.

10. The method as recited in claim 1, wherein adjusting the traffic flow is performed based upon the measured traffic flow for at least a portion of the assigned forwarding addresses.

11. The method as recited in claim 1, wherein adjusting the traffic flow is performed based upon the measured traffic flow for each of the assigned forwarding addresses.

12. The method as recited in claim 1, wherein adjusting the traffic flow comprises:

re-assigning at least one of the first plurality of forwarding addresses to the second gateway device, wherein after re-assigning the at least one of the first plurality of forwarding addresses is no longer assigned to the first gateway device.

13. The method as recited in claim 1, wherein the first gateway device and the second gateway device each operate as an Active Virtual Forwarder in accordance with the Gateway Load Balancing Protocol.

14. The method as recited in claim 1, wherein the first plurality of forwarding addresses is different from the second plurality of forwarding addresses.

15. A method of controlling traffic flow in a load-sharing redundancy group comprising a set of gateway devices including a first gateway device and a second gateway device which forward packets sent from hosts, the method comprising:

assigning a first address set to the first gateway device, wherein the first address set comprises a plurality of forwarding addresses, further wherein the first gateway device operates as a first active gateway to forward packets sent by hosts and addressed to forwarding addresses in the first address set;

assigning a second address set to the second gateway device, wherein the second address set comprises a plurality forwarding addresses, further wherein the second gateway device operates as a second active gateway to forward packets sent by hosts and addressed to forwarding addresses in the second address set;

measuring the traffic flow to each forwarding address;

adjusting the measured traffic flow by changing allocation of the forwarding addresses based upon the measured traffic flow;

wherein the load-sharing redundancy group provides failover services in the event that one of the gateway devices ceases operation.

16. The method of claim 15 wherein adjusting the traffic flow comprises instructing a host to use the assigned forwarding address having the lowest measured traffic flow on one of the set of gateway devices, the one of the set of gateway devices having the lowest measured traffic flow.

17. The method of claim 15 wherein the forwarding addresses are virtual Media Access Control (vMAC) addresses.

18. The method of claim 15 wherein the first gateway device is a first router and the second gateway device is a second router.

19. The method of claim 15 wherein adjusting the traffic flow comprises re-assigning one of the forwarding addresses from the first address set to the second address set.

20. The method as claim 15, wherein the first gateway device actively forwards packets simultaneously with the second gateway device, and wherein the second gateway device actively forwards packets simultaneously with the first gateway device.

21. The method as recited in claim 15, wherein the first gateway device and the second gateway device each operate as an Active Virtual Forwarder in accordance with the Gateway Load Balancing Protocol.

22. The method as recited in claim 15, wherein the first address set is different from the second address set.

23. A computer readable medium encoded with instructions executable by a computer, the instructions specifying a method of controlling traffic flow in a load-sharing redundancy group comprising a set of gateway devices including a first gateway device and a second gateway device which forward packets from hosts, the method comprising:

assigning a first plurality of forwarding addresses to the first gateway device, further wherein the first gateway device forwards packets sent by hosts and addressed to the first plurality of forwarding addresses;

assigning a second plurality of forwarding addresses to the second gateway device, further wherein the second gateway device forwards packets sent by hosts and addressed to the second plurality of forwarding addresses;

measuring the traffic flow for each of the assigned forwarding addresses; and

adjusting the traffic flow by changing allocation of the forwarding addresses based upon the measured traffic flow;

wherein the load-sharing redundancy group provides failover services in the event that one of the gateway devices ceases operation;

wherein the first gateway device actively forwards packets and the second gateway device actively forwards packets simultaneously with the first gateway device.

24. The computer readable medium of claim 23 wherein the load-sharing redundancy group implements Cisco Gateway Load Balancing Protocol (GLBP) and further wherein the first gateway device is a first router and the second gateway device is a second router.

25. The computer readable medium of claim 23 wherein each forwarding address is a Media Access Control (MAC) address.

26. The computer readable medium of claim 25 wherein each Media Access Control (MAC) address is a virtual Media Access Control (vMAC) address.

27. The computer readable medium of claim 23 wherein adjusting the traffic flow comprises altering the distribution of forwarding addresses to hosts.

28. The computer readable medium of claim 27 wherein altering the distribution of forwarding addresses to hosts comprises replying to Address Resolution Protocol (ARP) inquiries from hosts using the forwarding address having the lowest measured traffic flow on one of the set of gateway devices, the one of the set of gateway devices having the lowest measured traffic flow.

29. The computer readable medium of claim 23 wherein adjusting the traffic flow comprises re-assigning a forwarding address to a different gateway device.

30. The computer readable medium of claim 23, the method further comprising:

comparing the measured traffic flow to a target traffic flow;

wherein the target traffic flow is equal distribution of traffic across the first gateway device and the second gateway device and further wherein adjusting the traffic flow comprises adjusting the traffic flow across the first gateway device and the second gateway device to more equally distribute the measured traffic flow between the first gateway device and the second gateway device.

31. An apparatus for controlling traffic flow in a load-sharing redundancy group comprising a set of gateway devices including a first gateway device and a second gateway device which forward packets sent from hosts, the apparatus comprising:

means for assigning a first plurality of forwarding addresses to the first gateway device, further wherein the first gateway device forwards packets sent by hosts and addressed to the first plurality of forwarding addresses;

means for assigning a second plurality of forwarding addresses to the second gateway device, further wherein the second gateway device forwards packets sent by hosts and addressed to the second plurality of forwarding addresses;

means for measuring the traffic flow for each of the assigned forwarding addresses; and

means for adjusting the traffic flow by changing allocation of the forwarding addresses based upon the measured traffic flow;

wherein the load-sharing redundancy group provides failover services in the event that one of the gateway devices ceases operation,

wherein the first gateway device actively forwards packets simultaneously with the second gateway device, and the second gateway device actively forwards packets simultaneously with the first gateway device.

32. The apparatus of claim 31 wherein the means for adjusting the traffic flow comprises means for altering the distribution of forwarding addresses to hosts.

33. The apparatus of claim 32 wherein the means for altering the distribution of forwarding addresses to hosts comprises means for replying to Address Resolution Protocol (ARP) inquiries from hosts such that the hosts are instructed to use the forwarding address having the lowest measured traffic flow on one of the set of gateway devices, the one of the set of gateway devices having the lowest measured traffic flow.

34. The apparatus of claim 31 wherein the means for adjusting the traffic flow comprises means for re-assigning a forwarding address to a different gateway device.

35. The apparatus of claim 31, further comprising:

means for comparing the measured traffic flow to a target traffic flow;

wherein the target traffic flow is equal distribution of traffic across the first gateway device and the second gateway device and further wherein the means for adjusting the traffic flow comprises means for adjusting the traffic flow across the first gateway device and the second gateway device to more equally distribute the measured traffic flow between the first gateway device and the second gateway device.

36. A primary gateway device controlling traffic flow in a load-sharing redundancy group comprising a set of gateway devices including the primary gateway device and a second gateway device which forward packets sent from hosts, the primary gateway device comprising:

one or more processors;

a memory in communication with at least one of the processors, wherein at least one of the processors and the memory;

assign a first plurality of forwarding addresses to the primary gateway device, further wherein the primary gateway device forwards packets sent by hosts and addressed to the first plurality of forwarding addresses;

assign a second plurality of forwarding addresses to the second gateway device, further wherein the second gateway device forwards packets sent by hosts and addressed to the second plurality of forwarding addresses;

measure the traffic flow for each of the assigned forwarding addresses in the primary gateway device and the second gateway device; and

adjust the traffic flow by changing allocation of the forwarding addresses;

wherein the load-sharing redundancy group provides failover services in the event that one of the gateway devices ceases operation;

wherein the first gateway device actively forwards packets simultaneously with the second gateway device, and the second gateway device actively forwards packets simultaneously with the first gateway device.

37. The primary gateway device of claim 36 wherein each forwarding address is a Media Access Control (MAC) address.

38. The primary gateway device of claim 37 wherein each Media Access Control (MAC) address is a virtual Media Access Control (vMAC) address.

39. The primary gateway device of claim 36 wherein adjusting the traffic flow comprises altering the distribution of forwarding addresses to hosts.

40. The primary gateway device of claim 39 wherein altering the distribution of forwarding addresses to hosts comprises replying to Address Resolution Protocol (ARP) inquiries from hosts, wherein replying includes instructing the hosts to use the forwarding address having the lowest measured traffic flow on one of the set of gateway devices, the one of the set of gateway devices having the lowest measured traffic flow.

41. The primary gateway device of claim 36 wherein adjusting the traffic flow comprises re-assigning a forwarding address to a different gateway device.

42. The primary gateway device of claim 36 wherein the primary gateway device is a first router and the second gateway device is a second router.

43. The primary gateway device of claim 36, wherein at least one of the processors and the memory:

compare the measured traffic flow to a target traffic flow;

wherein the target traffic flow is equal distribution of traffic across the primary gateway device and the second gateway device and further wherein adjusting the traffic flow comprises adjusting the traffic flow across the primary gateway device and the second gateway device to more equally distribute the measured traffic flow between the primary gateway device and the second gateway device.

44. The primary gateway device as recited in claim 36, wherein the primary gateway device operates as an Active Virtual Forwarder in accordance with the Gateway Load Balancing Protocol.

45. A primary gateway device controlling traffic flow in a load-sharing redundancy group comprising a set of gateway devices including the primary gateway device and a second gateway device which forward packets sent from hosts, the gateway device comprising:

one or more processors;

a memory in communication with at least one of the processors, wherein at least one of the processors and the memory;

assign a first address set to the primary gateway device, wherein the first address set comprises a plurality of forwarding addresses, further wherein the primary gateway device forwards packets sent by hosts and addressed to forwarding addresses in the first address set;

assign a second address set to the second gateway device, wherein the second address set comprises a plurality forwarding addresses, further wherein the second gateway device forwards packets sent by hosts and addressed to forwarding addresses in the second address set;

measure the traffic flow to each forwarding address; and

adjust the measured traffic flow by changing allocation of the forwarding addresses;

wherein the load-sharing redundancy group provides failover services in the event that one of the gateway devices ceases operation;

wherein both the first gateway device and the second gateway device forward packets at a given point in time.

46. The primary gateway device of claim 45 wherein adjusting the traffic flow comprises instructing a host to use the assigned forwarding address having the lowest measured traffic flow on one of the set of gateway devices, the one of the set of gateway devices having the lowest measured traffic flow.

47. The primary gateway device of claim 45 wherein the forwarding addresses are virtual Media Access Control (vMAC) addresses.

48. The primary gateway device of claim 45 wherein the primary gateway device is a first router and the second gateway device is a second router.

49. The primary gateway device of claim 45 wherein adjusting the traffic flow comprises re-assigning one of the forwarding addresses from the first address set to the second address set.