Connection rate limiting for server load balancing and transparent cache switching

• US 8,554,929 B1
• Filed: 05/03/2002
• Issued: 10/08/2013
• Est. Priority Date: 05/03/2002
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Foundry Networks LLC (Broadcom, Inc.)
• Inventors: Szeto, Ronald W., Cheung, David Chun Ying, Jalan, Rajkumar
• Primary Examiner(s): BAROT, BHARAT
• Application Number:
  US10/139,076
• Time in Patent Office: 4,176 Days
• Field of Search: 709203-238, 718102-108
• US Class Current: 709/229
• CPC Class Codes: H04L 63/0218 Distributed architectures, e.g. distributed firewalls
• CPC Class Codes: H04L 63/1458 Denial of Service
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1031 Controlling of the operation of servers by a load balancer, e.g. adding or removing servers that serve requests
• CPC Class Codes: H04L 67/1036 Load balancing of requests to servers for services different from user content provisioning, e.g. load balancing across domain name servers
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching

Abstract

Each service in a computer network may have a connection rate limit. The number of new connections per time period may be limited by using a series of rules. In a specific embodiment of the present invention, a counter is increased each time a server is selected to handle a connection request. For each service, connections coming in are tracked. Therefore, the source of connection-request packets need not be examined. Only the destination service is important. This saves significant time in the examination of the incoming requests. Each service may have its own set of rules to best handle the new traffic for its particular situation. For server load balancing, a reset may be sent to the source address of the new connection request. For transparent cache switching, the connection request may be forwarded to the Internet.

Claims

1. A computer implemented method comprising:

by a network device, incrementing a counter each time a new server load balancing service connection request is received, the request identifying one of a plurality of sources, the request further identifying a destination server load balancing service, the server load balancing service connection request comprising a request to connect to a server load balancing service, the counter indicating a quantity of requests to connect to the server load balancing service from the plurality of sources;

sending a reset toward the source of the request if the counter increases at a rate exceeding a predetermined server load balancing service connection rate limit; and

granting the new server load balancing service request if the counter has not increased at a rate exceeding the predetermined server load balancing service connection rate limit.

2. The method of claim 1, further including resetting the counter to zero if the elapsed time since the last counter reset is greater than a predetermined time interval.

3. The method of claim 2, wherein the predetermined server load balancing service connection rate limit is a number of transactions per predetermined time interval.

4. The method of claim 1, further comprising detecting a new server load balancing service connection request by looking at a SYN bit of an incoming transmission control protocol (TCP) packet.

5. The method of claim 1 wherein the incrementing further comprises incrementing the counter without examining the source address.

6. The method of claim 1 wherein the incrementing is based at least in part on the identification of the destination server load balancing service.

7. The method of claim 1, further comprising detecting a new server load balancing service connection request by looking for any user datagram protocol (UDP) packets.

8. An apparatus comprising:

means for, by a network device, incrementing a counter each time a new server load balancing service connection request is received, the request one of a plurality of sources, the request further identifying a destination server load balancing service, the server load balancing service connection request comprising a request to connect to the server load balancing service, the counter indicating a quantity of requests to connect to the server load balancing service from the plurality of sources;

means for sending a reset toward the source of the request if the counter increases at a rate exceeding a predetermined server load balancing service connection rate limit; and

means for granting the new server load balancing service request if the counter has not increased at a rate exceeding the predetermined server load balancing service connection rate limit.

9. The apparatus of claim 8, further including means for resetting the counter to zero if the elapsed time since the last counter reset is greater than a predetermined time interval.

10. The apparatus of claim 9, wherein the predetermined server load balancing service connection rate limit is a number of transactions per predetermined time interval.

11. The apparatus of claim 8, further comprising means for detecting a new server load balancing service connection request by looking at a SYN bit of an incoming transmission control protocol (TCP) packet.

12. The apparatus of claim 8 wherein the means for incrementing a counter each time a new server load balancing service connection request is received further comprises means for incrementing the counter without examining the source address.

13. The apparatus of claim 8 wherein the means for incrementing further comprises means for incrementing the counter based at least in part on the identification of the destination server load balancing service.

14. The apparatus of claim 8 further comprising means for detecting a new connection request for the service on the server by looking for any user datagram protocol (UDP) packets.

15. A non-transitory program storage device readable by a machine, embodying a program of instructions executable by the machine to perform a method, the method comprising:

by a network device, incrementing a counter each time a new server load balancing service connection request is received, the request identifying one of a plurality of sources, the request further identifying a destination server load balancing service, the server load balancing service connection request comprising a request to connect to a server load balancing service, the counter indicating a quantity of requests to connect to the server load balancing service from the plurality of sources;

sending a reset toward the source of the request if the counter increases at a rate exceeding a predetermined server load balancing service connection rate limit; and

granting the new server load balancing service request if the counter has not increased at a rate exceeding the predetermined server load balancing service connection rate limit.

16. The program storage device of claim 15, the method further including resetting the counter to zero if the elapsed time since the last counter reset is greater than a predetermined time interval.

17. The program storage device of claim 16, wherein the predetermined server load balancing service connection rate limit is a number of transactions per predetermined time interval.

18. The program storage device of claim 15, the method further comprising detecting a new server load balancing service connection request by looking at a SYN bit of an incoming transmission control protocol (TCP) packet.

19. The program storage device of claim 15 wherein the incrementing further comprises incrementing the counter without examining the source address.

20. The program storage device of claim 15 wherein the incrementing is based at least in part on the identification of the destination server load balancing service.

21. The program storage device of claim 15, the method further comprising detecting a new server load balancing service connection request by looking for any user datagram protocol (UDP) packets without a session.

22. An apparatus comprising:

a memory; and

one or more components coupled to the memory and configured to;

increment a counter each time a new server load balancing service connection request comprising a request to connect to a server load balancing service is received, the request identifying one of a plurality of sources, the request further identifying a destination server load balancing service, the server load balancing service connection request comprising a request to connect to the server load balancing service, the counter indicating a quantity of requests to connect to the server load balancing service from the plurality of sources;

send a reset toward the source of the request if the counter increases at a rate exceeding a predetermined server load balancing service connection rate limit; and

grant the new server load balancing service request if the counter has not increased at a rate exceeding the predetermined server load balancing service connection rate limit.

23. The apparatus of claim 22 wherein the apparatus is further configured to reset the counter to zero if the elapsed time since the last counter reset is greater than a predetermined time interval.

24. The apparatus of claim 23 wherein the predetermined server load balancing service connection rate limit is a number of transactions per predetermined time interval.

25. The apparatus of claim 22 wherein the apparatus is further configured to detect a new server load balancing service connection request by looking at a SYN bit of an incoming transmission control protocol (TCP) packet.

26. The apparatus of claim 22 wherein the apparatus is further configured to incrementing the counter without examining the source address.

27. The apparatus of claim 22 wherein the new server load balancing service connection request counter incrementer is further configured to increment the counter based at least in part on the identification of the destination server load balancing service.

28. The apparatus of claim 22, wherein the new server load balancing service connection request detector comprises a user datagram protocol packet session examiner.

29. A computer implemented method comprising:

by a network device, incrementing a number each time a new server load balancing service connection request is received, the request identifying one of a plurality of sources, the request further identifying a destination server load balancing service, the server load balancing service connection request comprising a request to connect to the server load balancing service, the number indicating a quantity of requests to connect to the server load balancing service from the plurality of sources;

sending a reset toward the source address of the request if the number increases at a rate exceeding a predetermined server load balancing service connection rate limit; and

granting the new server load balancing service request if the number has not increased at a rate exceeding the predetermined server load balancing service connection rate limit.

30. The method of claim 29, further comprising resetting the number to zero if the elapsed time since the last number reset is greater than a predetermined time interval.

31. The method of claim 29, wherein the predetermined connection rate limit is a number of transactions per predetermined time interval.

32. The method of claim 29, further comprising detecting a new server load balancing service connection request by looking at a SYN bit of an incoming transmission control protocol (TCP) packet.

33. The method of claim 29 wherein the incrementing is based at least in part on the identification of the destination server load balancing service.

34. The method of claim 29, further comprising detecting a new server load balancing service connection request by looking for any user datagram protocol (UDP) packets.

35. An apparatus comprising:

means for, by a network device, incrementing a number each time a new server load balancing service connection request is received, the request identifying one of a plurality of sources, the request further identifying a destination server load balancing service, the server load balancing service connection request comprising a request to connect to a server load balancing service, the number indicating a quantity of requests to connect to the server load balancing service from the plurality of sources;

means for sending a reset toward the source address of the request if the number increases at a rate exceeding a predetermined server load balancing service connection rate limit; and

means for granting the new server load balancing service request if the number has not increased at a rate exceeding the predetermined server load balancing service connection rate limit.

36. The apparatus of claim 35, further comprising means for resetting the number to zero if the elapsed time since the last number reset is greater than a predetermined time interval.

37. The apparatus of claim 35, wherein the predetermined connection rate limit is a number of transactions per predetermined time interval.

38. The apparatus of claim 35, further comprising means for detecting a new server load balancing service connection request by looking at a SYN bit of an incoming transmission control protocol (TCP) packet.

39. The apparatus of claim 35 wherein the incrementing is based at least in part on the identification of the destination server load balancing service.

40. The apparatus of claim 35, further comprising means for detecting a new server load balancing service connection request by looking for any user datagram protocol (UDP) packets without a session.

41. A non-transitory program storage device readable by a machine, embodying a program of instructions executable by the machine to perform a method, the method comprising:

by a network device, incrementing a number each time a new server load balancing service connection request is received, the request identifying one of a plurality of sources, the request further identifying a destination server load balancing service, the server load balancing service connection request comprising a request to connect to a server load balancing service, the number indicating a quantity of requests to connect to the server load balancing service from the plurality of sources;

sending a reset toward the source address of the request if the number increases at a rate exceeding a predetermined server load balancing service connection rate limit; and

granting the new server load balancing service request if the number has not increased at a rate exceeding the predetermined server load balancing service connection rate limit.

42. The program storage device of claim 41, the method further comprising resetting the number to zero if the elapsed time since the last number reset is greater than a predetermined time interval.

43. The program storage device of claim 41, wherein the predetermined connection rate limit is a number of transactions per predetermined time interval.

44. The program storage device of claim 41, the method further comprising detecting a new server load balancing service connection request by looking at a SYN bit of an incoming transmission control protocol (TCP) packet.

45. The program storage device of claim 41 wherein the incrementing is based at least in part on the identification of the destination server load balancing service.

46. The program storage device of claim 41, the method further comprising detecting a new server load balancing service connection request by looking for any user datagram protocol (UDP) packets.

47. An apparatus comprising:

a memory; and

one or more components coupled to the memory and configured to;

increment a number each time a new server load balancing service connection request comprising a request to connect to a server load balancing service is received, the request identifying one of a plurality of sources, the request further identifying the server load balancing service, the number indicating a quantity of requests to connect to the server load balancing service from the plurality of sources;

send a reset toward the source address of the request if the number increases at a rate exceeding a predetermined server load balancing service connection rate limit; and

grant the new server load balancing service request if the number has not increased at a rate exceeding the predetermined server load balancing service connection rate limit.

48. The apparatus of claim 47, the apparatus further configured to reset the number to zero if the elapsed time since the last number reset is greater than a predetermined time interval.

49. The apparatus of claim 47, wherein the predetermined connection rate limit is a number of transactions per predetermined time interval.

50. The apparatus of claim 47, the apparatus further configured to detect a new server load balancing service connection request by looking at a SYN bit of an incoming transmission control protocol (TCP) packet.

51. The apparatus of claim 47 wherein the incrementing is based at least in part on the identification of the destination server load balancing service.

52. The apparatus of claim 47, the apparatus further configured to detect a new server load balancing service connection request by looking for any user datagram protocol (UDP) packets.