Connectivity fault management (CFM) in networks with link aggregation group connections

• US 7,768,928 B2
• Filed: 07/11/2006
• Issued: 08/03/2010
• Est. Priority Date: 07/11/2006
• Status: Active Grant

• Current Assignee: Correct Transmission LLC
• Original Assignee: Corrigent Systems Ltd. (Orckit-Corrigent )
• Inventors: Harel, Rafi, Solomon, Ronen
• Primary Examiner(s): Patel, Ajit
• Application Number:
  US11/483,650
• Publication Number:
  US 20080016402A1
• Time in Patent Office: 1,484 Days
• Field of Search: None
• US Class Current: 370/241.1
• CPC Class Codes: H04L 1/243 at the transmitter, using a loop-back
• CPC Class Codes: H04L 41/06 Management of faults, events, alarms or notifications
• CPC Class Codes: H04L 41/26 using dedicated tools for LAN [Local Area Network] management
• CPC Class Codes: H04L 43/0811 by checking connectivity
• CPC Class Codes: H04L 43/10 Active monitoring, e.g. heartbeat, ping or trace-route
• CPC Class Codes: H04L 45/245 Link aggregation, e.g. trunking
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A maintenance entity for an Ethernet Connectivity Fault Management (CFM) domain. The maintenance entity comprises a port definer module and a connection which is connected to a group of aggregated link. The port definer module examines a designated link of the group by forwarding CFM messages via the designated link.

Claims

1. A maintenance entity in an Ethernet Connectivity Fault Management (CFM) domain, comprising:

a port definer module;

a connection configured to be connected to a group of aggregated physical links, said group of links comprising a single logical link to which packets are directed;

said port definer module being configured to designate any one physical link of said logical link as required for examining of said designated physical link of said logical link, said designation comprising forwarding at least one CFM message to said logical link in such a way as to be forwarded over said logical link specifically via said designated physical link, said designation being available for each physical link separately, thereby allowing examination according to requirement of any physical link of said logical link.

2. The maintenance entity of claim 1, wherein said port definer module is configured to examine a designated link of said group by receiving at least one CFM message via said designated link.

3. The maintenance entity of claim 1, wherein said maintenance entity is one member of the group consisting of:

a maintenance entity point (MEP) and a maintenance entity group (MEG) intermediate point (MIP).

4. The maintenance entity of claim 1, wherein said CFM message is one member of the group consisting of:

a continuity check message;

a loopback message;

a Link trace message;

an alarm indication signal;

a remote defect indication;

a locked signal function;

a test signal;

a maintenance communication channel;

a Vendor specific check; and

an experimental operation, administration and maintenance (OAM) check.

5. The maintenance entity of claim 1, wherein said CFM domain is implemented on one member of the group consisting of:

a virtual local area network (V-LAN), a local area network (LAN), and an Ethernet service network.

6. The maintenance entity of claim 1, wherein said designated link is associated with an additional maintenance entity of said CFM domain.

7. The maintenance entity of claim 6, wherein said additional maintenance entity is associated with a certain flow point.

8. The maintenance entity of claim 7, wherein said flow point is one member of the group consisting of:

a switch port, a gateway port, a network port, a network node comprising a processing unit, and a network node comprising a switching unit.

9. The maintenance entity of claim 1, wherein said CFM message comprises at least one LAG member field, said at least one LAG member field being configured for specifying said designated link.

10. The maintenance entity of claim 9, wherein said forwarding is done according to said at least one LAG member field.

11. The maintenance entity of claim 1, wherein said port definer module is configured to distinguish between said at least one CFM message and other messages.

12. The maintenance entity of claim 11, wherein said other messages are forwarded according to at least one balancing algorithm, said at least one CFM message being forwarded according to a coupled specification.

13. The maintenance entity of claim 1, further comprising a user interface configured for allowing a system operator to separately mark each aggregated link of said group, said forwarding being done according to a match between said marks and said at least one CFM message.

14. A system for using Connectivity Fault Management (CFM) functions to examine aggregated link connections, said system comprising:

a plurality of maintenance entities connected to a CFM domain, each one of said maintenance entities comprising a port definer module;

at least one group of aggregated physical links comprising a single logical link, configured for connecting a first and a second of said plurality of maintenance entities;

the port definer module of said first maintenance entity being configured to designate any physical link as required of said single logical link, and examine said designated link of said single logical link by forwarding at least one CFM message to said second maintenance entity via said logical link in such a way that said CFM message is passed specifically via said designated physical link, thereby to allow examination of any physical link of said single logical link.

15. The system of claim 14, wherein each of said maintenance entities is one member of the group consisting of:

maintenance entity points (MEPs) and maintenance entity group (MEG) intermediate points (MIPs).

16. The system of claim 14, wherein said CFM message is one member of the group consisting of:

a continuity check message;

a loopback message;

a Link trace message;

an alarm indication signal;

a remote defect indication;

a locked signal function;

a test signal;

a maintenance communication channel;

a Vendor specific check; and

an experimental operation, administration and maintenance (OAM) check.

17. The system of claim 14, wherein said CFM domain is implemented on one member of the group consisting of:

a virtual local area network (V-LAN), a local area network (LAN), and an Ethernet service network.

18. The system of claim 14, wherein said CFM message comprises at least one LAG member field, said at least one LAG member field being configured for specifying said designated link.

19. The system of claim 18, wherein said forwarding is done according to said at least one LAG member field.

20. The system of claim 14, wherein said port definer module is configured to distinguish between said at least one CFM message and other messages.

21. The system of claim 20, wherein said other messages are forwarded according to at least one balancing algorithm, said at least one CFM message being forwarded according to a coupled specification.

22. A method for implementing connectivity fault management (CFM) functions in a network, comprising:

a) connecting first and second maintenance entities via a link aggregation group (LAG), said LAG comprising a single logical link made up of a plurality of physical links;

b) using said first maintenance entity to select one of said physical links as a designated link for forwarding a CFM message via a designated link of said LAG; and

c) verifying the functioning of said designated link by analyzing the outcome of said forwarding, each of said physical links being selectable as said designated link, thereby to provide for examination as required for any physical link of said group comprising said single logical link.

23. The method of claim 22, wherein said designated link is directly associated with said second maintenance entity.

24. The method of claim 23, wherein said first and second maintenance entities are associated with respective flow points.

25. The method of claim 24, wherein each one of said flow points is one member of the group consisting of:

a switch port, a gateway port, a network port, a network node comprising a processor unit, and a network node comprising a switching unit.

26. The method of claim 22, further comprising a step between step (a) and step (b) of marking aggregated links of said LAG, wherein said forwarding of step (b) is done according to a match between said CFM message and one of said marks.

27. The method of claim 22, wherein each one of said first and second maintenance entities is a member of the group consisting of:

a maintenance entity point (MEP) and a maintenance entity group (MEG) intermediate point (MIP).

28. The method of claim 22, wherein said CFM message is one member of the group consisting of:

a Continuity Check Message;

a Loopback Message;

a Link Trace Message;

an Alarm Indication Signal;

a Remote Defect Indication;

a Locked Signal Function;

a Test Signal;

a Maintenance Communications Channel;

a Vendor Specific check; and

an Experimental operation, administration and maintenance (OAM) check.

29. The method of claim 22, wherein said network is one member of the group consisting of:

a virtual local area network (V-LAN), a local area network (LAN), and an Ethernet service network.

30. The method of claim 22, wherein said CFM message comprises at least one LAG member field, said at least one LAG member field being configured for specifying said designated link.

31. The method of claim 30, wherein said forwarding of step (b) is done according to said at least one LAG member field.

32. An entity for maintaining connectivity in an Ethernet Connectivity Fault Management (CFM) domain, comprising:

a port definer module;

a connection configured to be connected to a group of aggregated physical links, said group of links comprising a single logical link to which packets are directed;

said port definer module being configured to designate any one physical link of said logical link as required for sending an Ethernet packet via said designated physical link of said logical link, said designation comprising forwarding at least one CFM message to said logical link in such a way as to be forwarded over said logical link specifically via said designated physical link, said designation being available for each physical link separately, thereby allowing forwarding via any specific physical link of said logical link and maintaining connectivity despite faults in some of said physical links.