Flexible scheduling of network devices within redundant aggregate configurations

• US 6,618,377 B1
• Filed: 03/30/1999
• Issued: 09/09/2003
• Est. Priority Date: 03/30/1999
• Status: Expired due to Fees

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Miriyala, Prasad
• Primary Examiner(s): Kizou, Hassan
• Assistant Examiner(s): LOGSDON, JOSEPH B
• Application Number:
  US09/281,621
• Time in Patent Office: 1,624 Days
• Field of Search: 370/216, 370/217, 370/218, 370/219, 370/220, 370/242, 370/244, 370/389, 370/395.1, 370/395.5, 370/395.52, 370/395.54, 370/241.1, 370/226, 370/250, 709/102, 709/105
• US Class Current: 370/395.1
• CPC Class Codes: H04L 12/5601 Transfer mode dependent, e.g. ATM
• CPC Class Codes: H04L 2012/5614 User Network Interface
• CPC Class Codes: H04L 2012/563 Signalling, e.g. protocols, reference model
• CPC Class Codes: H04L 2012/5667 IP over ATM
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04L 61/00 Network arrangements, protocols or services for addressing or naming
• CPC Class Codes: H04L 61/10 of different types
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/60 Scheduling or organising the servicing of application requests, e.g. requests for application data transmissions using the analysis and optimisation of the required network resources admission control or resource allocation H04L47/70
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A protocol is provided for backing up ATM network devices should they fail. The protocol is implemented in a system running ATMARP and supporting IP over ATM. In the protocol, multiple ATM network devices are combined in a “standby group” and share a common IP address. When an active member of the standby group fails, one of the other members of the standby group takes over ATM responsibility for the functions of the failed device. An ATMARP Server determines which member of a standby group should handle IP packets destined for that group.

Claims

1. A method of providing a network service using a standby group of ATM network devices within an ATM network, each ATM network device within the standby group having its own ATM address and sharing a non-ATM network address with other members of the standby group, the method comprising:

determining that a first member of the standby group of network devices is not available to provide the network service; and

identifying a second member of the standby group of network devices to provide the network service,

wherein determining that the first member of the standby group of network devices is not available comprises at least one of (i) detecting that the first member has not opened a virtual circuit within a predetermined period, and (ii) detecting that the first member has not sent a KEEP ALIVE message within a predetermined period.

2. The method of claim 1 wherein a first member of said group of ATM network devices is actively servicing a collection of network destinations without assistance from the remainder of the network ATM devices in the group of ATM network devices.

3. The method of claim 1 wherein the method is implemented by an ATM server in the ATM network.

4. The method of claim 3 wherein the ATM server can form virtual connections with each member of the standby group.

5. The method of claim 4 wherein the ATM server can form virtual connections with each member of the standby group using an ARP protocol.

6. The method of claim 1 wherein the non-ATM address being shared is unique to the group of network devices.

7. The method of claim 6 wherein the non-ATM address being shared is an IP address.

8. The method of claim 1 wherein determining that the first member of the standby group of network devices is not available to provide the network service includes detecting that the first member is not active.

9. The method claim 1 wherein the availability of each of the network devices in the group of network devices is stored in a single entity.

10. The method of claim 1 wherein each of the network devices in the standby group of network devices has a priority ranking it with respect to the remaining network devices in the group of network devices.

11. The method of claim 1, wherein identifying the second member comprises determining that the second member has the highest priority of the remaining members of the standby group.

12. The method of claim 11, wherein determining that the second member has the highest priority occurs prior to identifying the second member of the standby group of network devices to provide the network service.

13. The method of claim 1, wherein identifying a second member of the standby group of network devices to provide the network service comprises using a list specifying members of the standby group and relative priorities of those members.

14. The method of claim 1, further comprising providing ARP replies identifying the ATM address of the second member of the standby group after identifying the second member.

15. On a first network device, a method of providing a network service using a standby group of ATM network devices within an ATM network, each ATM network device within the standby group having its own ATM address and sharing a non-ATM network address with other members of the standby group, the method comprising:

determining that the first network device is available by at least one of (i) detecting that the first network device has opened a virtual circuit within a predetermined period, and (ii) detecting that the first network device has sent a KEEP ALIVE message within a predetermined period;

sending a notification identifying the first network device by ATM address and the shared non-ATM network address; and

receiving one or more packets destined for the shared non-ATM network address.

16. The method of claim 15, wherein the notification also specifies a priority of the first network device within the standby group.

17. The method of claim 15, wherein the sending the notification comprises sending an ATMARP request.

18. The method of claim 15, wherein the first network device exists in a standby state prior to receiving the one or more packets destined for the shared non-ATM network address, and wherein while in the standby state, the first network device does not receive packets destined for the shared non-ATM network address.

19. The method of claim 15, wherein the shared non-ATM network address is a standby group IP address and the one or more packets destined for the standby group IP address.

20. A method of using a network device in an ATM network, the network device having at least one non-ATM network address, the method comprising:

assigning the network device to a first group of network devices having a first non-ATM network address; and

promoting the network device from a standby status to an active status in which the network device services the non-ATM network address,

wherein promoting the network device is performed in response to at least one of (i) detecting that another network device in the first group of network devices has not opened a virtual circuit within a predetermined period, and (ii) detecting that another network device in the first group of network devices has not sent a KEEP ALIVE message within a predetermined period.

21. The method of implementing a network device of claim 20 further comprising assigning the network device to a second group of network devices having a second non-ATM network address which is different from the first non-ATM network address.

22. The method of implementing a network device of claim 21 wherein promoting the network device from the standby status to the active status is performed based on a priority designation of the network device relative to priority designations of other network devices within the first group of network devices.

23. A method of using a network device in an ATM network, the network device having at least one non-ATM network address, the method comprising:

assigning the network device to a group of network devices having a shared non-ATM network address;

determining whether the network device is not available by at least one of (i) determining whether the network device has not opened a virtual circuit within a predetermined period, and (ii) determining whether the network device has not sent a KEEP ALIVE message within a predetermined period; and

if the network device is not available, changing the network device from an active status in which the network device services the non-ATM network address to a standby status in which the network device does not service the non-ATM network address.

24. A server for use in an ATM network including a plurality of network devices, the server comprising:

one or more processors; and

at least one interface for establishing a connection between the server and a network device of the plurality of network devices,

wherein the one or more processors are configured to provide a collection of entries wherein each entry in the collection of entries corresponds to a network device of the plurality of network devices, wherein one or more of the entries includes the corresponding network device'"'"'s ATM address, a shared non-ATM address used by the corresponding network device and one or more others of the plurality of network devices, and a value used in determining whether the network device corresponding to the entry is currently acting as the device having the non-ATM address, and

wherein the one or more processors are configured to adjust the value when it is determined that the network device currently acting as the device having the non-ATM address is no longer available as determined by at least one of (i) detecting that the network device has not opened a virtual circuit within a predetermined period, and (ii) detecting that the network device has not sent a KEEP ALIVE message within a predetermined period.

25. The server of claim 24, wherein the processor is configured to run an ATMARP protocol.

26. The server of claim 24, wherein the at least one interface is an ATM interface.

27. The server of claim 24, wherein the connection is an ATM virtual circuit connection.

28. The server of claim 24 wherein the shared non-ATM address for a first entry in the collection of entries is the same as the shared non-ATM address for a second entry in the collection of entries.

29. The server of claim 28 wherein the value for the first entry in the collection of entries is compared with the value for the second entry in the collection of entries for determining whether the network device corresponding to the entry is currently acting as the device the non-ATM address.

30. The server of claim 24 wherein the collection of entries is stored in non-volatile memory.

31. The server of claim 24, wherein the collections of entries is stored as a logical table.

32. The network device of claim 24, further comprising a value used in determining whether the network device is currently acting as the device having the non-ATM address.

33. A network device for use in an ATM network having a plurality of network devices and a server, the network device comprising:

one or more processors;

at least one interface for establishing a connection between the network device and a second network device;

an ATM address; and

a non-ATM address shared by at least one other network device in the plurality of network devices of the ATM network,

wherein the one or more processors is configured to perform at least one of the following functions;

(i) to open a virtual circuit within a predetermined period, and (ii) to send a KEEP ALIVE message within a predetermined period.

34. The network device of claim 33 further including a second non-ATM address.

35. The network device of claim 34 wherein the second non-ATM address is shared with at least one other network device in the plurality of network devices of the ATM network.

36. The network device of claim 33 wherein said at least one interface includes a plurality of sub-interfaces.

37. The network device of claim 33 wherein the connection is a virtual connection.

38. The network device of claim 37 wherein the virtual connection is an SVC.

39. The network device of claim 33 wherein the processor is configured to run as act as an ATMARP Client.

40. The network device of claim 33 wherein the network device is a router or switch.

41. The network device of claim 33 further including a second ATM address.

42. A computer-readable medium on which is provided a computer code for providing a network service using a standby group of ATM network devices within an ATM network, each ATM network device within the standby group having its own ATM address and sharing a non-ATM network address with other members of the standby group, the computer code comprising:

instructions for determining that a first member of the standby group of network devices is not available to provide the network service; and

instructions for identifying a second member of the standby group of network devices to provide the network service,

wherein determining that the first member of the standby group of network devices is not available comprises at least one of (i) detecting that the first member has not opened a virtual circuit within a predetermined period, and (ii) detecting that the first member has not sent a KEEP ALIVE message within a predetermined period.

43. The computer-readable medium of claim 42 wherein a first member of said group of ATM network devices is actively servicing a collection of network destinations without assistance from the remainder of the network ATM devices in the group of ATM network devices.

44. The computer-readable medium of claim 42 wherein the method is implemented by an ATM server in the ATM network.

45. The computer-readable medium of claim 44 wherein the ATM server can form virtual connections with each member of the standby group.

46. The computer-readable medium of claim 45 wherein the ATM server can form virtual connections with each member of the standby group using an ARP protocol.

47. The computer-readable medium of claim 42 wherein the non-ATM address being shared is unique to the group of network devices.

48. The computer-readable medium of claim 47 wherein the non-ATM address being shared is an IP address.

49. The computer-readable medium of claim 42 wherein determining that the first member of the standby group of network devices is not available to provide the network service includes detecting that the first member is not active.

50. The computer-readable medium claim 42 wherein the availability of each of the network devices in the group of network devices is stored in a single entity.

51. The computer-readable medium of claim 42 wherein each of the network devices in the standby group of network devices has a priority ranking it with respect to the remaining network devices in the group of network devices.

52. The computer-readable medium of claim 42 wherein identifying the second member comprises determining that the second member has the highest priority of the remaining members of the standby group.

53. The computer-readable medium of claim 52 wherein determining that the second member has the highest priority occurs prior to identifying the second member of the standby group of network devices to provide the network service.

54. The computer-readable medium of claim 42, wherein identifying a second member of the standby group of network devices to provide the network service comprises using a list specifying members of the standby group and relative priorities of those members.

55. The computer-readable medium of claim 42, further comprising instructions for providing ARP replies identifying the ATM address of the second member of the standby group after identifying the second member.

56. A network service system using a standby group of ATM network devices within an ATM network, each ATM network device within the standby group having its own ATM address and sharing a non-ATM network address with other members of the standby group, the system comprising:

means for determining that a first member of the standby group of network devices is not available to provide the network service; and

means for identifying a second member of the standby group of network devices to provide the network service,

wherein determining that the first member of the standby group of network devices is not available comprises at least one of (i) detecting that the first member has not opened a virtual circuit within a predetermined period, and (ii) detecting that the first member has not sent a KEEP ALIVE message within a predetermined period.