Backup CRF VLAN

• US 6,657,951 B1
• Filed: 03/10/1999
• Issued: 12/02/2003
• Est. Priority Date: 11/30/1998
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Potter, Kenneth H. Jr., Carroll, David A., Adams, Kara J., Fitzgerald, John K., Kramling, Gary William
• Primary Examiner(s): Hsu, Alpus H.
• Assistant Examiner(s): SHAND, ROBERTA A
• Application Number:
  US09/266,198
• Time in Patent Office: 1,728 Days
• Field of Search: 370/216, 370/217, 370/218, 370/222, 370/225, 370/228, 370/244, 370/245, 370/248, 370/250, 370/400, 370/401, 370/406, 370/409, 370/434, 370/445, 370/447, 370/452, 709/238, 709/239, 709/220, 709/221, 709/249, 709/251, 709/229, 714/1, 714/2, 714/3, 714/4
• US Class Current: 370/222
• CPC Class Codes: H04L 12/433 with asynchronous transmission, e.g. token ring, register insertion
• CPC Class Codes: H04L 12/4604 LAN interconnection over a backbone network, e.g. Internet, Frame Relay

Abstract

A backup CRF VLAN arrangement provides an alternate, redundant path for traffic between undistributed Concentrator Relay Functions (CRFs) located on separate switches interconnected by trunk links of a distributed token ring bridge. The backup CRF virtual local area network (VLAN) arrangement defines a backup network path which may be utilized if a primary active path is not a valid path to a backup network. Notably, the backup network comprises a special type of CRF that is distributed among the switches, but that has only one port active at any given time.

Claims

1. A method for providing a redundant path for traffic between undistributed Concentrator Relay Functions (CRFs) located on different switches interconnected by trunk links of a distributed token ring (TR) bridge, the method comprising the steps of:

providing a backup network having a CRF with associated ports, the CRF distributed among the switches and having only one port active at a time;

connecting the backup network between the switches of the distributed TR bridge, the backup network having a primary active path and a backup network path to the distributed TR bridge; and

utilizing the backup network path if the primary active path is not a valid path to the backup network.

2. The method of claim 1 wherein the step of utilizing further comprises the step of utilizing the backup network path in response to activation of a TR connection when a trunk link within the distributed TR bridge fails.

3. The method of claim 1 further comprising the steps of:

associating a virtual local area network (VLAN) with the distributed CRF; and

configuring a database of each switch in the distributed TR bridge to define the distributed CRF and associated VLAN as a backup CRF VLAN.

4. The method of claim 3 wherein the step of configuring further comprises the step of manually configuring the DRiP database of each switch in the distributed bridge.

5. The method of claim 3 wherein the step of configuring further comprises the step of employing a conventional protocol configured to set up and manage VLANs in a network.

6. The method of claim 3 wherein the database is a distributed ring protocol (DRiP) database having a plurality of entries and wherein the step of configuring comprises the step of asserting a backup bit for an entry of the database to reflect a backup CRF VLAN status of the backup CRF VLAN.

7. The method of claim 6 wherein the step of asserting comprises the step of denoting that ports on the CRF VLAN are not disabled when the DRiP database indicates that another switch has a port configured on the same CRF VLAN.

8. The method of claim 7 further comprising the step of ensuring that only one port of the distributed CRF is active at a time to thereby avoid loop problems associated with active, dual-attached ports.

9. The method of claim 8 further comprising the steps of:

implementing a conflict resolution policy when a port on more than one switch of the distributed CRF is active and configured at the same time; and

selecting one port of a switch to be active for the backup CRF VLAN.

10. The method of claim 9 wherein the step of selecting comprises the step of selecting a port of a switch having a smaller medium access control address value.

11. The method of claim 9 wherein the step of selecting comprises the step of selecting a port of a switch having a larger medium access control address value.

42. A computer readable media, comprising:

said computer readable media having instructions for execution on a processor for the practice of the method of claim 1 or claim 21.

43. Electromagnetic signals propagating on a computer network, comprising:

said electromagnetic signals carrying instructions for execution on a processor for the practice of the method of claim 1 or claim 21.

12. A system for providing a redundant path for traffic between undistributed Concentrator Relay Functions (CRFs) located on different switches interconnected by trunk links of a distributed token ring (TR) bridge, the system comprising:

a backup network coupled between the switches, the backup network utilized in response to activation of a TR connection when a trunk link within the distributed TR bridge fails, the backup network including a CRF that is distributed among the switches and having only one port active at a time.

13. The system of claim 12 further comprising a backup network path which may be utilized if a primary active path is not a valid path to a backup network.

14. The system of claim 12 wherein a virtual local area network (VLAN) is associated with the distributed CRF, and wherein the distributed CRF and associated VLAN are defined as a backup CRF VLAN by configuring a database of each switch in the distributed TR bridge.

15. The system of claim 14 wherein the database is a distributed ring protocol (DRiP) database having a plurality of entries and wherein the DRiP database is configured to reflect a backup CRF VLAN status by asserting a backup bit for a particular entry.

16. The system of claim 15 wherein assertion of the backup bit denotes that ports on the CRF VLAN are not disabled when the DRiP database indicates that another switch has a port configured on the same CRF VLAN.

17. The system of claim 16 further comprising a DRiP core process for implementing a conflict resolution policy when a port on more than one switch of the distributed CRF is active and configured at the same time, the conflict resolution policy selecting one port of a switch to be active for the backup CRF VLAN.

18. The system of claim 12 wherein the backup network is an ATMLane network.

19. The system of claim 12 wherein the trunk links are interswitch link (ISL) trunk links.

20. The system of claim 17 wherein the conflict resolution policy is based on the medium access control address of each switch.

21. A method for operating a switch, comprising:

connecting a first port of said switch to a trunk link, said trunk link forming a path of a distributed token ring (TR) bridge to provide a path for traffic between an undistributed Concentrator Relay Function (CRF) in said switch and other undistributed Concentrator Relay Functions located on other switches;

providing a second port of said switch to connect to said distributed token ring (TR) bridge to provide a portion of a backup network, said second port having a second undistributed CRF in said switch; and

utilizing said second port as a backup port if the primary active port does not connect to a valid path to the network, the backup port providing a path from said switch to said distributed token ring (TR) bridge.

22. The method of claim 21 further comprising:

utilizing the backup network path in response to activation of a TR connection when a trunk link within the distributed TR bridge fails.

23. The method of claim 21 further comprising:

associating a virtual local area network (VLAN) with the distributed CRF; and

configuring a database of each switch in the distributed TR bridge to define the distributed CRF and associated VLAN as a backup CRF VLAN.

24. The method of claim 23 further comprising:

manually configuring the DRiP database of each switch in the distributed bridge.

25. The method of claim 23 further comprising:

employing a conventional protocol configured to set up and manage VLANs in a network.

26. The method of claim 23 further comprising:

asserting a backup bit for an entry of the database to reflect a backup CRF VLAN status of the backup CRF VLAN, and the database is a distributed ring protocol (DRiP) database having a plurality of entries.

27. The method of claim 26 further comprising:

denoting that ports on the CRF VLAN are not disabled when the DRiP database indicates that another switch has a port configured on the same CRF VLAN.

28. The method of claim 27 further comprising:

ensuring that only one port of the distributed CRF is active at a time to thereby avoid loop problems associated with active, dual-attached ports.

29. The method of claim 28 further comprising:

implementing a conflict resolution policy when a port on more than one switch of the distributed CRF is active and configured at the same time; and

selecting one port of a switch to be active for the backup CRF VLAN.

30. The method of claim 29 further comprising:

selecting a port of a switch having a smaller medium access control address value.

31. The method of claim 29 further comprising:

selecting a port of a switch having a larger medium access control address value.

32. A switch, comprising:

a first port of said switch connected to a trunk link, said trunk link forming a path of a distributed token ring (TR) bridge to provide a path for traffic between an undistributed Concentrator Relay Function (CRF) in said switch and other undistributed Concentrator Relay Functions located on other switches;

a second port of said switch connected to said distributed token ring (TR) bridge to provide a portion of a backup network, said second port having a second undistributed CRF in said switch; and

a circuit to utilize said second port as a backup port if the primary active port does not connect to a valid path to the network, the backup port providing a path from said switch to said distributed token ring (TR) bridge.

33. The apparatus of claim 32 further comprising:

a backup network path which may be utilized by said switch if a primary active path is not a valid path to a backup network.

34. The apparatus of claim 32, further comprising:

said switch forming a part of a distributed CRF, a virtual local area network (VLAN) associated said distributed CRF, and the distributed CRF and associated VLAN are defined as a backup CRF VLAN by configuring a database of said switch.

35. The apparatus of claim 34 further comprising:

said database is a distributed ring protocol (DRiP) database having a plurality of entries and the DRiP database is configured ion said switch to reflect a backup CRF VLAN status by asserting a backup bit for a particular entry.

36. The apparatus of claim 35 further comprising:

assertion of the backup bit denotes that ports on the CRF VLAN are not disabled when the DRiP database indicates that another switch has a port configured on the same CRF VLAN.

37. The apparatus of claim 35 further comprising:

a DRiP core process in said switch, said DRiP core process for implementing a conflict resolution policy when a port on more than one switch of the distributed CRF is active and configured at the same time, the conflict resolution policy selecting one port of a switch to be active for the backup CRF VLAN.

38. The apparatus of claim 37 further comprising:

the conflict resolution policy is based on the medium access control address of each switch.

39. The apparatus of claim 32 further comprising:

the backup network is an ATMLane network.

40. The apparatus of claim 32 further comprising:

the trunk links are interswitch link (ISL) trunk links.

41. A switch, comprising:

means for connecting a first port of said switch to a trunk link, said trunk link forming a path of a distributed token ring (TR) bridge to provide a path for traffic between an undistributed Concentrator Relay Function (CRF) in said switch and other undistributed Concentrator Relay Functions located on other switches;

means for providing a second port of said switch to connect to said distributed token ring (TR) bridge to provide a portion of a backup network, said second port having a second undistributed CRF in said switch; and

means for utilizing said second port as a backup port if the primary active port does not connect to a valid path to the network, the backup port providing a path from said switch to said distributed token ring (TR) bridge.

44. A method for operating a switch, comprising:

connecting a first port of said switch to a trunk link, said trunk link forming a path of a distributed token ring (TR) bridge to provide a path for traffic between an undistributed Concentrator (CRF) in said switch and other undistributed Concentrators located on other switches;

providing a second port of said switch to connect to said distributed token ring (TR) bridge to provide a portion of a backup network, said second port having a second undistributed CRF in said switch; and

utilizing said second port as a backup port if the primary active port does not connect to a valid path to the network, the backup port providing a backup network path from said switch to said distributed token ring (TR) bridge.

45. The method of claim 44 further comprising:

using a concentrator relay function in the switch as the concentrator, the concentrator relay function described in the IEEE 802.5 standard.

46. The method of claim 44 further comprising:

utilizing the backup network path in response to activation of a TR connection when a trunk link within the distributed TR bridge fails.

47. The method of claim 44 further comprising:

associating a virtual local area network (VLAN) with the distributed CRF; and

configuring a database of each switch in the distributed TR bridge to define the distributed CRF and associated VLAN as a backup CRF VLAN.

48. The method of claim 44 further comprising:

manually configuring a DRIP database of each switch in the distributed bridge.

49. The method of claim 44 further comprising:

employing a conventional protocol configured to set up and manage VLANs in a network.

50. The method of claim 44 further comprising:

asserting a backup bit for an entry of the database to reflect a backup CRF VLAN status of the backup CRF VLAN, and the database is a distributed ring protocol (DRiP) database having a plurality of entries.

51. The method of claim 44 further comprising:

denoting that ports on the CRF VLAN are not disabled when the DRiP database indicates that another switch has a port configured on the same CRF VLAN.

52. The method of claim 44 further comprising:

ensuring that only one port of the distributed CRF is active at a time to thereby avoid loop problems associated with active, dual-attached ports.

69. A computer readable media, comprising:

said computer readable media having instructions for execution on a processor for the practice of the method of claim 44 or claim 53.

70. Electromagnetic signals propagating on a computer network, comprising:

said electromagnetic signals carrying instructions for execution on a processor for the practice of the method of claim 44 or claim 53.

53. A method for operating a switch, comprising:

connecting a first port of said switch to a trunk link, said trunk link forming a path of a distributed token ring (TR) bridge to provide a path for traffic between an undistributed Concentrator (CRF) in said switch and other undistributed Concentrators located on other switches;

providing a second port of said switch to connect to said distributed token ring (TR) bridge to provide a portion of a backup network, said second port having a second undistributed CRF in said switch;

utilizing said second port as a backup port if the primary active port does not connect to a valid path to the network, the backup port providing a backup network path from said switch to said distributed token ring (TR) bridge; and

utilizing the backup network path in response to activation of a TR connection when a trunk link within the distributed TR bridge fails.

54. The method of claim 53 further comprising:

using a concentrator relay function in the switch as the concentrator, the concentrator relay function described in the IEEE 802.5 standard.

55. A switch, comprising:

a first port of said switch connected to a trunk link, said trunk link forming a path of a distributed token ring (TR) bridge to provide a path for traffic between an undistributed Concentrator (CRF) in said switch and other undistributed Concentrators located on other switches;

a second port of said switch connected to said distributed token ring (TR) bridge to provide a portion of a backup network, said second port having a second undistributed CRF in said switch; and

a circuit to utilize said second port as a backup port if the primary active port does not connect to a valid path to the network, the backup port providing a path from said switch to said distributed token ring (TR) bridge.

56. The apparatus as in claim 55, further comprising:

the concentrator is a concentrator relay function in the switch, the concentrator relay function described in a IEEE 802.5 standard.

57. The apparatus of claim 55 further comprising:

a backup network path which may be utilized by said switch if a primary active path is not a valid path.

58. The apparatus of claim 55, further comprising:

said switch forming a part of a distributed CRF, a virtual local area network (VLAN) associated said distributed CRF, and the distributed CRF and associated VLAN are defined as a backup CRF VLAN by configuring a database of said switch.

59. The apparatus of claim 58 further comprising:

said database is a distributed ring protocol (DRiP) database having a plurality of entries and the DRiP database is configured ion said switch to reflect a backup CRF VLAN status by asserting a backup bit for a particular entry.

60. The apparatus of claim 55 further comprising:

assertion of the backup bit denotes that ports on the CRF VLAN are not disabled when the DRiP database indicates that another switch has a port configured on the same CRF VLAN.

61. The apparatus of claim 55 further comprising:

a DRIP core process in said switch, said DRIP core process for implementing a conflict resolution policy when a port on more than one switch of the distributed CRF is active and configured at the same time, the conflict resolution policy selecting one port of a switch to be active for the backup CRF VLAN.

62. The apparatus of claim 55 further comprising:

the conflict resolution policy is based on the medium access control address of each switch.

63. The apparatus of claim 55 further comprising:

the backup network is an ATMLane network.

64. The apparatus of claim 55 further comprising:

the trunk links are interswitch link (ISL) trunk links.

65. A switch, comprising:

a first port of said switch connected to a trunk link, said trunk link forming a path of a distributed token ring (TR) bridge to provide a path for traffic between an undistributed Concentrator (CRF) in said switch and other undistributed Concentrators located on other switches;

a second port of said switch connected to said distributed token ring (TR) bridge to provide a portion of a backup network, said second port having a second undistributed CRF in said switch;

a circuit to utilize said second port as a backup port if the primary active port does not connect to a valid path to the network, the backup port providing a backup network path from said switch to said distributed token ring (TR) bridge; and

a circuit to utilize the backup network path in response to activation of a TR connection when a trunk link within the distributed TR bridge fails.

66. A switch, comprising:

means for connecting a first port of said switch to a trunk link, said trunk link forming a path of a distributed token ring (TR) bridge to provide a path for traffic between an undistributed Concentrator (CRF) in said switch and other undistributed Concentrators located on other switches;

means for providing a second port of said switch to connect to said distributed token ring (TR) bridge to provide a portion of a backup network, said second port having a second undistributed CRF in said switch; and

means for utilizing said second port as a backup port if the primary active port does not connect to a valid path to the network, the backup port providing a backup network path from said switch to said distributed token ring (TR) bridge.

67. The apparatus of claim 66 further comprising:

means for using a concentrator relay function in the switch as the concentrator, the concentrator relay function described in the IEEE 802.5 standard.

68. The apparatus of claim 66, further comprising:

means for utilizing the backup network path in response to activation of a TR connection when a trunk link within the distributed TR bridge fails.