Loop failure handling method and switch

• US 10,764,085 B2
• Filed: 06/05/2019
• Issued: 09/01/2020
• Est. Priority Date: 12/06/2016
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Xie, Ying, Zhao, Shaoqi, Cheng, Pu
• Primary Examiner(s): Daya, Tejis
• Application Number:
  US16/432,397
• Publication Number:
  US 20190288871A1
• Time in Patent Office: 454 Days
• CPC Class Codes: H04L 12/42 Loop networks
• CPC Class Codes: H04L 12/437 Ring fault isolation or reconfiguration for SDH/SONET ring networks H04J3/085
• CPC Class Codes: H04L 12/4641 Virtual LANs, VLANs, e.g. virtual private networks [VPN] LAN interconnection over a bridge based backbone H04L12/462; encapsulation techniques H04L12/4633; routing of packets H04L45/00; packet switches H04L49/00; virtual private networks for security H04L63/0272
• CPC Class Codes: H04L 2012/4629 using multilayer switching, e.g. layer 3 switching
• CPC Class Codes: H04L 2101/622 Layer-2 addresses, e.g. medium access control [MAC] addresses
• CPC Class Codes: H04L 41/0654 using network fault recovery ring fault isolation or reconfiguration in loop networks without recovery actions by a network management system H04L12/437
• CPC Class Codes: H04L 41/0661 by reconfiguring faulty entities
• CPC Class Codes: H04L 41/0677 Localisation of faults

Abstract

A switch receives a first packet, where the first packet includes a source media access control MAC address. The switch obtains a first flapping count corresponding to the source MAC address. The switch determines, based on the first flapping count, whether a loop failure occurs in a network in which the switch is located. When the loop failure occurs in the network in which the switch is located, the switch obtains a flapping port set corresponding to the source MAC address. The switch determines a primary port in the plurality of ports, where the primary port is a port that must be suppressed. The switch enables a flooding suppression function on the primary port, where the flooding suppression function is used to suppress forwarding of a received flooding packet by the primary port.

Claims

1. A loop failure handling method, applied to a switch, wherein the method comprises:

receiving a first packet comprising a source media access control (MAC) address, wherein the source MAC address is a MAC address of a device generating the first packet;

obtaining a first flapping count corresponding to the source MAC address, wherein the first flapping count indicates a quantity of times that the source MAC address flaps between different ports of the switch;

determining, based on the first flapping count, whether a loop failure occurs in a network in which the switch is located;

obtaining a flapping port set corresponding to the source MAC address when the loop failure occurs in the network in which the switch is located, wherein the flapping port set comprises a plurality of ports of the switch to which the source MAC address flaps sequentially;

determining a primary port in the plurality of ports, wherein the primary port is a port that must be suppressed; and

enabling a flooding suppression function on the primary port, wherein the flooding suppression function suppresses forwarding of a received flooding packet by the primary port.

2. The method according to claim 1, further comprising:

determining a secondary port in the plurality of ports, wherein the secondary port is a port suppressed optionally; and

enabling the flooding suppression function on the secondary port,

wherein the secondary port is an access-side port or a network-side port of the switch when the network in which the switch is located is an Ethernet network; and

wherein the secondary port is an access-side port of the switch when the network in which the switch is located is a Transparent Interconnection of Lots of Links (TRILL) network or a Virtual eXtensible Local Area Network (VXLAN).

3. The method according to claim 1, wherein after determining that the loop failure is recovered, the method further comprises sending an unsuppress instruction to each suppressed port, wherein the unsuppress instruction triggers a port receiving the unsuppress instruction to forward a received flooding packet.

4. The method according to claim 1, wherein obtaining the first flapping count corresponding to the source MAC address comprises:

searching a flapping information table based on the source MAC address to obtain a flapping information entry corresponding to the source MAC address, wherein the flapping information entry comprises the flapping port set and the first flapping count; and

obtaining the first flapping count from the flapping information entry.

5. The method according to claim 4, wherein the flapping information entry further comprises a flapping start time corresponding to the source MAC address wherein the first flapping count is a quantity of times that the source MAC address flags between different ports of the switch, starting from the flapping start time, and wherein determining, based on the first flapping count, whether the loop failure occurs in the network in which the switch is located comprises:

comparing the first flapping count with a preset flapping threshold; and

determining that the loop failure occurs in the network in which the switch is located, when the first flapping count is greater than or equal to the preset flapping threshold;

or

determining a first time difference between a current system time and the flapping start time;

calculating a ratio of the first flapping count to the first time difference to obtain a first flapping frequency;

comparing the first flapping frequency with a preset flapping frequency threshold; and

determining that the loop failure occurs in the network in which the switch is located, when the first flapping frequency is greater than or equal to the preset flapping frequency threshold.

6. The method according to claim 4, wherein the flapping information entry further comprises a last update time of a MAC entry corresponding to the source MAC address in a MAC address table of the switch, and wherein determining that the loop failure is recovered comprises:

calculating a second time difference between a current system time and the last update time of the MAC entry; and

determining that the loop failure is recovered, when the second time difference is greater than or equal to a specified duration.

7. The method according to claim 4, wherein before searching the flapping information table based on the source MAC address, the method further comprises:

determining a first port receiving the first packet; and

updating the flapping information table based on the first port when the first port is different from a prior port corresponding to the source MAC address, wherein the prior port is a port in a MAC entry corresponding to the source MAC address when the switch receives the first packet.

8. The method according to claim 7, wherein the flapping information table comprises the flapping information entry corresponding to the source MAC address, wherein the first port is already in the flapping port set, and wherein updating the flapping information table based on the first port comprises:

changing a last update time in the flapping information entry to a time at which the switch updates the MAC entry based on the first port; and

adding 1 to a prior flapping count in the flapping information entry to obtain the first flapping count, wherein the prior flapping count is a flapping count in the flapping information entry before the flapping information table is updated.

9. The method according to claim 7, wherein the flapping information table comprises the flapping information entry corresponding to the source MAC address, wherein the first port is not in the flapping port set, and wherein updating the flapping information table based on the first port comprises:

adding the first port to the flapping port set sequentially;

changing a last update time in the flapping information entry to a time at which the switch updates the MAC entry based on the first port; and

adding 1 to a prior flapping count in the flapping information entry to obtain the first flapping count, wherein the prior flapping count is a flapping count in the flapping information entry before the flapping information table is updated.

10. The method according to claim 7, wherein the flapping information table does not comprise the flapping information entry corresponding to the source MAC address, and wherein updating the flapping information table based on the first port comprises:

adding, to the flapping information table, the flapping information entry corresponding to the source MAC address;

adding the prior port and the first port sequentially to the flapping port set in the flapping information entry;

adding, to the flapping information entry, the flapping start time and a last update time of the MAC entry corresponding to the source MAC address, wherein the flapping start time is a time at which the switch determines that the first port is different from the prior port, and wherein the last update time of the MAC entry is a time at which the switch updates the MAC entry based on the first port; and

setting a flapping count in the flapping information entry to 1 in order to obtain the first flapping count.

11. The method according to claim 1, wherein when the network in which the switch is located is an Ethernet, the primary port is an access-side port or a network-side port of the switch, or wherein when the network in which the switch is located is a Transparent Interconnection of Lots of Links (TRILL) network or a Virtual eXtensible Local Area Network (VXLAN), the primary port is an access side port of the switch.

12. A switch, comprising:

a plurality of ports;

a first memory is configured to store program code; and

a processor coupled to the first memory and the plurality of ports, wherein the processor is configured to invoke the program code to perform;

receiving a first packet comprising a source media access control (MAC) address, wherein the source MAC address is a MAC address of a device that generates the first packet;

obtaining a first flapping count corresponding to the source MAC address, wherein the first flapping count indicates a quantity of times that the source MAC address flaps between different ports of the switch;

determining, based on the first flapping count, whether a loop failure occurs in a network in which the switch is located;

obtaining a flapping port set corresponding to the source MAC address when the loop failure occurs in the network in which the switch is located, wherein the flapping port set comprises a plurality of ports of the switch to which the source MAC address flaps sequentially;

determining a primary port in the plurality of ports, wherein the primary port is a port that must be suppressed; and

enabling a flooding suppression function on the primary port, wherein the flooding suppression function suppresses forwarding of a received flooding packet by the primary port.

13. The switch according to claim 12, wherein the processor is further configured to perform:

determining a secondary port in the plurality of ports, wherein the secondary port is a port suppressed optionally; and

enabling the flooding suppression function on the secondary port,

wherein the secondary port is an access-side port or a network-side port of the switch when the network in which the switch is located is an Ethernet network, or

wherein the secondary port is an access-side port of the switch when the network in which the switch is located is a Transparent Interconnection of Lots of Links (TRILL) network or a Virtual eXtensible Local Area Network (VXLAN).

14. The switch according to claim 12, wherein the processor is further configured to perform, after determining that the loop failure is recovered, sending an unsuppress instruction to each suppressed port, wherein the unsuppress instruction triggers a port receiving the unsuppress instruction to forward a received flooding packet.

15. The switch according to claim 12, wherein obtaining the first flapping count corresponding to the source MAC address comprises:

searching a flapping information table based on the source MAC address to obtain a flapping information entry corresponding to the source MAC address, wherein the flapping information entry comprises the flapping port set and the first flapping count; and

obtaining the first flapping count from the flapping information entry.

16. The switch according to claim 15, wherein the flapping information entry further comprises a flapping start time corresponding to the source MAC, wherein the first flapping count is a quantity of times that the source MAC address flags between different ports of the switch, starting from the flapping start time, and wherein determining, based on the first flapping count, whether the loop failure occurs in the network in which the switch is located comprises:

comparing the first flapping count with a preset flapping threshold; and

determining that the loop failure occurs in the network in which the switch is located, when the first flapping count is greater than or equal to the preset flapping threshold;

or

determining a first time difference between a current system time and the flapping start time;

calculating a ratio of the first flapping count to the first time difference to obtain a first flapping frequency;

comparing the first flapping frequency with a preset flapping frequency threshold; and

determining that the loop failure occurs in the network in which the switch is located.

17. The switch according to claim 15, wherein the flapping information entry further comprises a last update time of a MAC entry corresponding to the source MAC address in a MAC address table of the switch, and wherein determining that the loop failure is recovered comprises:

calculating a second time difference between a current system time and the last update time of the MAC entry; and

determining that the loop failure is recovered, when the second time difference is greater than or equal to a specified duration.

18. The switch according to claim 15, wherein before searching the flapping information table based on the source MAC address, the processor is further configured to perform:

determining a first port receiving the first packet; and

updating the flapping information table based on the first port when the first port is different from a prior port corresponding to the source MAC address, wherein the prior port is a port in a MAC entry corresponding to the source MAC address when the switch receives the first packet.

19. A network system comprising a plurality of switches, wherein each switch comprises:

a plurality of ports;

a first memory configured to store program code; and

a processor coupled to the first memory and the plurality of ports, wherein the processor is configured to invoke the program code to perform;

receiving a first packet comprising a source media access control (MAC) address, wherein the source MAC address is a MAC address of a device that generates the first packet;

obtaining a first flapping count corresponding to the source MAC address, wherein the first flapping count indicates a quantity of times that the source MAC address flaps between different ports of the switch;

determining, based on the first flapping count, whether a loop failure occurs in a network in which the switch is located;

obtaining a flapping port set corresponding to the source MAC address when the loop failure occurs in the network in which the switch is located, wherein the flapping port set comprises a plurality of ports of the switch to which the source MAC address flaps sequentially;

determining a primary port in the plurality of ports, wherein the primary port is a port that must be suppressed; and

enabling a flooding suppression function on the primary port, wherein the flooding suppression function suppresses forwarding of a received flooding packet by the primary port.

20. The network system according to claim 19, wherein the processor is further configured to perform:

determining a secondary port in the plurality of ports, wherein the secondary port is a port suppressed optionally; and

enabling the flooding suppression function on the secondary port,

wherein the secondary port is an access-side port or a network-side port of the switch when the network in which the switch is located is an Ethernet network, or

wherein the secondary port is an access-side port of the switch when the network in which the switch is located is a Transparent Interconnection of Lots of Links (TRILL) network or a Virtual eXtensible Local Area Network (VXLAN).