Methods, systems, and computer readable media for providing N-node multi-switch link aggregation groups (MLAGs)

• US 9,385,942 B2
• Filed: 04/30/2014
• Issued: 07/05/2016
• Est. Priority Date: 04/30/2014
• Status: Active Grant

• Current Assignee: Extreme Networks, Inc.
• Original Assignee: Extreme Networks, Inc.
• Inventors: Grosser, Donald B. Jr., Ramamurthy, Shankara
• Primary Examiner(s): Pham, Chi H
• Assistant Examiner(s): HOM, SHICK C
• Application Number:
  US14/266,784
• Publication Number:
  US 20150319083A1
• Time in Patent Office: 797 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H04L 12/4625 Single bridge functionality, e.g. connection of two networks over a single bridge
• CPC Class Codes: H04L 41/0661 by reconfiguring faulty entities
• CPC Class Codes: H04L 41/0668 by dynamic selection of recovery network elements, e.g. replacement by the most appropriate element after failure
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/245 Link aggregation, e.g. trunking
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A system for providing at least one node of an n-node multi-switch link aggregation group (MLAG) includes a packet forwarding device for receiving a packet destined for at least one n-node MLAG, n being an integer greater than 2. The packet forwarding device includes a packet forwarding database for storing packet forwarding rules for the at least one n-node MLAG. The packet forwarding device further includes a processing element for forwarding, blocking forwarding of, or redirecting the packet in accordance with one of the packet forwarding rules defined for the n-node MLAG group in the packet forwarding database.

Claims

1. A system for providing at least one node of an n-node multi-switch link aggregation groups (MLAGs), the system comprising:

a packet forwarding device for receiving a packet destined for at least one n-node MLAG, n being an integer greater than two, the packet forwarding device including;

a packet forwarding database for storing packet forwarding rules for the at least one n-node MLAG; and

a processing element for forwarding, blocking forwarding of, or redirecting the packet in accordance with the packet forwarding rules in packet forwarding database; and

an MLAG module for updating the packet forwarding rules in the packet forwarding database in response to changes in status of the n-node MLAG or an interswitch connection (ISC) that carries packets between nodes in the n-node MLAG.

2. The system of claim 1 wherein, in response to a single interswitch connection (ISC) failure and no MLAG failures, the packet forwarding device is configured to allow packets to be forwarded to all ports on the packet forwarding device associated with the at least one n-node MLAG so that the at least one n-node MLAG can operate at full bandwidth.

3. The system of claim 1 wherein, in response to failure of a single MLAG port of the packet forwarding device associated with the at least one n-node MLAG and no interswitch connection failures, the packet forwarding device is configured to redirect packets destined for the failed MLAG port to an alternate MLAG port.

4. The system of claim 1 wherein the packet forwarding device is configured to utilize a topology discovery protocol to discover connections with other packet forwarding devices associated with the at least one n-node MLAG and to automatically configure at least a portion of the packet forwarding database based on the discovered connections.

5. The system of claim 1 wherein the packet forwarding device is configured to utilize a protocol for automatically detecting events that trigger updates to the packet forwarding rules for the at least one n-node MLAG.

6. The system of claim 1 wherein the packet forwarding device includes first and second ports for respectively connecting to first and second interswitch connections (ISCs) and wherein the packet forwarding database includes the following rules when all MLAG ports and ISC ports associated with all of the packet forwarding devices in the n-node MLAG are operational, and wherein the packet forwarding devices in the n-node MLAG are connected to each other via the ISCs in a ring topology:

(1) all layer 2 traffic received on either of the first and second interswitch connections is blocked from being forwarded to an MLAG port; and

(2) layer 2 traffic received on the first interswitch connection is prevented from being forwarded on the second interswitch connection.

7. The system of claim 6 wherein, in response to failure of a single MLAG port, the packet forwarding device is configured to:

if the single failed MLAG port is on a node adjacent to the packet forwarding device, modify rule (1) to unblock forwarding of traffic received on the second interswitch connection to a peer MLAG port of the failed MLAG port; and

if the single failed MLAG port is on the packet forwarding device, add the following rule to the packet forwarding database;

unicast traffic destined for the failed MLAG port is redirected to the second interswitch connection.

8. The system of claim 6 wherein, in response to failure of two non-adjacent ports within a single MLAG, the packet forwarding device is configured to:

if the packet forwarding device is adjacent to one of the failures, modify rule (1) unblock of forwarding traffic received on the second interswitch connection to peer a MLAG port of the failed MLAG ports; and

if one of the failed ports is on the packet forwarding device, add the following rule to the packet forwarding database;

(3) unicast traffic destined for the failed MLAG port is redirected to the second interswitch connection.

9. The system of claim 6 wherein, in response to failure of two adjacent ports within a single MLAG, the packet forwarding device is configured to:

if the packet forwarding device is adjacent to the failure, modify rule (1) to unblock forwarding of traffic received on the first interswitch connection to a peer MLAG port of the failed MLAG ports; and

if one of the failed ports is on the packet forwarding device, to add the following rule to the n-node MLAG forwarding rules database;

(3) unicast traffic destined for the failed MLAG port is redirected to the first interswitch connection if the first interswitch connection of the first type is unblocked and otherwise, unicast traffic is redirected to the second interswitch connection.

10. The system of claim 6 wherein, in response to failure of three ports within the same MLAG, the packet forwarding device is configured to, if none of the MLAG ports on the packet forwarding device has a failure, modify rule (1) to unblock forwarding of traffic from the first interswitch connection to the MLAG port.

11. The system of claim 6 wherein, in response to a single interswitch connection failure, the packet forwarding device is configured to unblock forwarding of traffic between the first and second interswitch connections.

12. The system of claim 11 wherein, in response to failure of an MLAG port on a node connected to the failed interswitch connection and adjacent to the packet forwarding, the packet forwarding device is configured to unblock ISC to MLAG port forwarding.

13. The system of claim 11 wherein, in response to failure of an MLAG port on a node not connected to the failed interswitch connection and adjacent to the packet forwarding device, and wherein the packet forwarding devices is not connected to the failed interswitch connection, the packet forwarding device is configured to unblock ISC to MLAG port forwarding and wherein the system further comprises a packet forwarding device connected to the failed interswitch connection and the node on which the MLAG port failure occurred, which is configured to disable the corresponding MLAG port.

14. The system of claim 1 wherein the packet forwarding device is configured to connect to other packet forwarding devices in the n-node MLAG via interswitch connections to form a linear topology.

15. A method for providing at least one node of an n-node multi-switch link aggregation groups (MLAGs), the method comprising:

in a packet forwarding device;

receiving a packet destined for at least one n-node MLAG, n being an integer greater than 2;

providing a packet forwarding database for storing packet forwarding rules for the at least one n-node MLAG;

controlling a processing element to forward, block forwarding of, or redirect the packet in accordance with the packet forwarding rules in the packet forwarding database; and

providing an MLAG module for updating the packet forwarding rules in the packet forwarding database in response to changes in status of the n-node MLAG or an interswitch connection (ISC) that carries packets between nodes in the n-node MLAG.

16. The method of claim 15 comprising, in response to a single interswitch connection (ISC) failure and no MLAG failures, allowing packets to be forwarded to all MLAG ports of the packet forwarding device associated with the at least one n-node MLAG so that the at least one n-node MLAG can operate at full bandwidth.

17. The method of claim 15 comprising, in response to failure of a single MLAG port of the packet forwarding device associated with the at least one n-node MLAG and no interswitch connection failures, redirecting packets destined for the failed MLAG port to an alternate MLAG port.

18. The method of claim 15 comprising utilizing a topology discovery protocol to discover connections between the packet forwarding device and other packet forwarding devices associated with the at least one n-node MLAG and automatically configuring at least a portion of the packet forwarding database based on the discovered connections.

19. The method of claim 15 comprising utilizing a protocol for automatically detecting events that trigger updates to the MLAG packet forwarding rules.

20. The method of claim 15 wherein the packet forwarding device includes first and second ports for respectively connecting to first and second interswitch connections (ISCs) of and wherein the packet forwarding database includes the following rules when all MLAG ports and ISC ports associated with all of the packet forwarding devices in the n-node MLAG are operational and wherein the packet forwarding devices in the n-node MLAG are connected to each other via the ISCs in a ring topology:

(1) all layer 2 traffic received on either of the first and second interswitch connections is blocked from being forwarded to an MLAG port; and

(2) layer 2 traffic received on the first interswitch connection is prevented from being forwarded on the second interswitch connection.

21. The method of claim 20 comprising, in response to failure of a single MLAG port:

if the single failed MLAG port is on a node adjacent to the packet forwarding device, modifying rule (1) to unblock forwarding of traffic received on the second interswitch connection to a peer MLAG port of the failed MLAG port; and

if the single failed MLAG port is on the packet forwarding device, adding the following rule to the packet forwarding database;

(3) unicast traffic destined for the failed MLAG port is redirected to the second interswitch connection.

22. The method of claim 20 comprising, in response to failure of two non-adjacent ports within a single MLAG:

if the packet forwarding device is adjacent to one of the failures, modifying rule (1) to unblock forwarding of traffic received on the second interswitch connection to a peer MLAG port of the failed MLAG ports; and

if one of the failed ports is on the packet forwarding device, adding the following rule to the packet forwarding database;

(3) unicast traffic destined for the failed MLAG port is redirected to the second interswitch connection.

23. The method of claim 20 comprising, in response to failure of two adjacent ports within a single MLAG:

if the packet forwarding device is adjacent to the failure, modifying rule (1) to forward traffic received on the first interswitch connection; and

if one of the failed ports is on the packet forwarding device, to adding the following rule to the n-node MLAG forwarding rules database;

(3) unicast traffic destined for the failed MLAG port is redirected to the first interswitch connection if the first interswitch connection of the first type is unblocked and otherwise, unicast traffic is redirected to the second interswitch connection.

24. The method of claim 20 comprising, in response to failure of three ports within the same MLAG, if none of the MLAG ports on the packet forwarding device has a failure, modifying rule (1) to unblock forwarding of traffic from the first interswitch connection to the MLAG port.

25. The method of claim 20 comprising, in response to a single interswitch connection failure, unblocking forwarding of traffic between the first and second interswitch connections.

26. The method of claim 25 wherein, in response to failure of an MLAG port on a node connected to the failed interswitch connection and adjacent to the packet forwarding device, unblocking ISC to MLAG port forwarding.

27. The method of claim 25 wherein, in response to failure of an MLAG port on a node not connected to the failed interswitch connection and adjacent to the packet forwarding device, and wherein the packet forwarding device is not connected to the failed interswitch connection, unblocking ISC to MLAG port forwarding and a packet forwarding device connected to the failed interswitch connection and the node on which the MLAG port failure occurred is configured to disable the corresponding MLAG port on the packet forwarding device.

28. The method of claim 15 wherein the packet forwarding device is configured to connect to other packet forwarding devices in the n-node MLAG via interswitch connections to form a linear topology.

29. A non-transitory computer readable medium having stored thereon executable instructions that when executed by the processor of a computer control the computer to perform steps comprising:

in a packet forwarding device;

receiving a packet destined for at least one n-node multi-switch link aggregation group (MLAG),

providing a packet forwarding database for storing packet forwarding rules for the at least one n-node MLAG;

controlling processing element to forward, block forwarding of, or redirect the packet in accordance with the packet forwarding rules in the packet forwarding database; and

providing an MLAG module for updating the packet forwarding rules in the packet forwarding database in response to changes in status of the n-node MLAG or an interswitch connection (ISC) that carries packets between nodes in the n-node MLAG.