Apparatus for link failure detection on high availability Ethernet backplane

• US 20040085894A1
• Filed: 12/20/2002
• Published: 05/06/2004
• Est. Priority Date: 10/31/2002
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Conexant Systems Incorporated (Synaptics Incorporated)
• Inventors: Lin, Eric (A.K.A. Changhwa), Chang, Rong-Feng, Wang, Linghsiao, Yik, James Ching-Shau
• Granted Patent: US 7,260,066 B2
• Time in Patent Office: Days
• US Class Current: 370/216
• CPC Class Codes: H04L 41/0663 Performing the actions predefined by failover planning, e.g. switching to standby network elements
• CPC Class Codes: H04L 41/0677 Localisation of faults
• 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 43/103 with adaptive polling, i.e. dynamically adapting the polling rate
• CPC Class Codes: H04L 49/1523 Parallel switch fabric planes
• CPC Class Codes: H04L 49/351 for local area network [LAN], e.g. Ethernet switches
• CPC Class Codes: H04L 49/552 by ensuring the integrity of packets received through redundant connections
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06

Abstract

A method for actively detecting link failures on a high availability backplane architecture. The backplane system includes redundant node boards operatively communicating with redundant switch fabric boards. Uplink ports of the node boards are logically grouped into trunk ports at one end of the communication link with the switch fabric boards. A probe packet is sent, and a probing timer is set whenever either a specified number of bad packets are received, or an idle timer expires. If a response to the probe packet is received before the probe timer expires then the link is deemed valid, otherwise the link is presumed to have failed. Preferably, either the node boards or the switch fabric boards are configured to properly handle a probe pack, which preferably has identical source and destination addresses.

Claims

1. A method for determining failure of a communications link, the steps comprising:

setting a timer for a predetermined interval;

resetting the timer to the predetermined interval whenever a valid packet is received; and

sending a probe packet and setting a probe timer when the timer expires.

2. The method of claim 1 further comprising changing the status of the communication link to a failure mode when the probe timer expires and a valid response to the probe packet has not been received.

3. The method of claim 1, the steps further comprising sending a probe packet and setting a probe timer after a predetermined number of consecutive invalid packets are received.

4. The method of claim 3 further comprising changing the status of the communication link to a failure mode when the probe timer expires and a valid response to the probe packet has not been received.

5. The method of claim 1 wherein the probe packet destination address is equal to the source address.

6. A computer-readable medium of instructions, comprising:

means for setting a timer for a predetermined interval;

means for resetting the timer to the predetermined interval whenever a valid packet is received; and

means for sending a probe packet and setting a probe timer when the timer expires.

7. The computer-readable medium of instructions of claim 6 further comprising means for changing the status of the communication link to a failure mode when the probe timer expires and a valid response to the probe packet has not been received.

8. The computer-readable medium of instructions of claim 6, further comprising means for sending a probe packet and setting a probe timer after a predetermined number of consecutive invalid packets are received.

9. The computer-readable medium of instructions of claim 8 further comprising means for changing the status of the communication link to a failure mode when the probe timer expires and a valid response to the probe packet has not been received.

10. An apparatus for link failure detection on a high availability Ethernet backplane, comprising:

means for setting a timer for a predetermined interval;

means for resetting the timer to the predetermined interval whenever a valid packet is received; and

means for sending a probe packet and setting a probe timer when the timer expires.

11. The apparatus for link failure detection on a high availability Ethernet backplane of claim 10 further comprising means for changing the status of the communication link to a failure mode when the probe timer expires and a valid response to the probe packet has not been received.

12. The apparatus for link failure detection on a high availability Ethernet backplane of claim 10, further comprising means for sending a probe packet and setting a probe timer after a predetermined number of consecutive invalid packets are received.

13. The apparatus for link failure detection on a high availability Ethernet backplane of claim 12 further comprising means for changing the status of the communication link to a failure mode when the probe timer expires and a valid response to the probe packet has not been received.

14. A backplane system comprising:

a plurality of node boards;

a plurality of switch fabric boards;

wherein each node of the plurality of node boards has a single link to each of the plurality of switch fabric boards

wherein at least one selected from the group consisting of the plurality of node boards and the plurality of switch fabric boards further comprises

means for setting a timer for a predetermined interval;

means for resetting the timer to the predetermined interval whenever a valid packet is received; and

means for sending a probe packet and setting a probe timer when the timer expires.

15. The backplane system of claim 14 wherein the at least one selected from the group consisting of the plurality of node boards and the plurality of switch fabric boards further comprises means for changing the status of the communication link to a failure mode when the probe timer expires and a valid response to the probe packet has not been received.

16. The backplane system of claim 14, wherein the at least one selected from the group consisting of the plurality of node boards and the plurality of switch fabric boards further comprises means for sending a probe packet and setting a probe timer after a predetermined number of consecutive invalid packets are received.

17. The backplane system of claim 16 wherein the at least one selected from the group consisting of the plurality of node boards and the plurality of switch fabric boards further comprises means for changing the status of the communication link to a failure mode when the probe timer expires and a valid response to the probe packet has not been received.

18. The backplane system of claim 14 wherein each switch fabric board further comprises a redirect table;

and

wherein when a switch fabric board detects a failed link, the switch fabric board communicates failed link data to the remaining switch fabric boards, causing the other switch fabric boards to update their redirect tables.

19. The backplane system of claim 14 wherein the probe timer is set for a minimum interval comprising a transmission and switching latency time period.

20. The backplane system of claim 14 wherein the probe packet is inserted in a distribution module on top of a Media Access Controller layer.