Traffic forwarding in a traffic-engineered link aggregation group

• US 7,912,091 B1
• Filed: 03/18/2009
• Issued: 03/22/2011
• Est. Priority Date: 03/18/2009
• Status: Active Grant

• Current Assignee: Extreme Networks, Inc.
• Original Assignee: Extreme Networks, Inc.
• Inventors: Kashyap, Prakash, Krishnan, Ram
• Primary Examiner(s): Vu, Thong H
• Application Number:
  US12/406,790
• Time in Patent Office: 734 Days
• Field of Search: 370/490, 370/400, 370/390, 370/389, 370/392, 370/244, 370/401, 709/224
• US Class Current: 370/490
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/22 Alternate routing
• 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 data packet is received at a network switch. The packet has a destination address that is reached via a Link Aggregation group on a virtual local area network (VLAN). A forwarding database lookup is performed to determine a Link Aggregation port reference number for the data packet on the VLAN. A Link Aggregation port table is then searched to determine the primary Link Aggregation port and a backup Link Aggregation port for forwarding the packet. A port array for ports in the Link Aggregation group is searched to determine if the primary Link Aggregation port is valid. If the primary port is valid, then the packet is forwarded on the primary Link Aggregation port. If the primary port is not valid, then the packet is forwarded on the backup Link Aggregation port.

Claims

1. A method, comprising:

receiving a data packet at a network switch, the packet having a destination address that is reached via a Link Aggregation group on a virtual local area network (VLAN);

performing a forwarding database lookup to determine a Link Aggregation port reference number for the data packet on the VLAN;

searching a Link Aggregation port table to determine a primary Link Aggregation port and a backup Link Aggregation port for forwarding the packet based at least on the Link Aggregation port reference number;

searching a port array to determine if the primary Link Aggregation port is valid;

forwarding the packet on the primary Link Aggregation port if the primary port is valid; and

forwarding the packet on the backup Link Aggregation port if the primary port is not valid.

2. The method of claim 1, wherein each Link Aggregation port in the port array is represented by 1 bit.

3. The method of claim 1, wherein performing the forwarding database lookup comprises directly accessing a forwarding table in hardware.

4. The method of claim 1, wherein performing the forwarding database lookup comprises accessing a software forwarding table.

5. The method of claim 2, further comprising:

setting a bit in the port array corresponding to a Link Aggregation port when the Link Aggregation port is operational; and

resetting the bit in the port array corresponding to the port when the Link Aggregation port is not operational.

6. A Non-transitory machine accessible storage medium containing instructions that, when executed, cause a machine to:

receive a data packet at a network switch, the packet having a destination address that is reached via a Link Aggregation group on a virtual local area network (VLAN);

perform a forwarding database lookup to determine a Link Aggregation port reference number for the data packet on the VLAN;

search a Link Aggregation port table to determine a primary Link Aggregation port and a backup Link Aggregation port for forwarding the packet based at least on the Link Aggregation port reference number;

search a port array to determine if the primary Link Aggregation port is valid;

forward the packet on the primary Link Aggregation port if the primary port is valid; and

forward the packet on the backup Link Aggregation port if the primary port is not valid.

7. The Non-transitory machine accessible storage medium of claim 6, wherein each Link Aggregation port in the port array is represented by 1 bit.

8. The Non-transitory machine accessible storage medium of claim 6, wherein the instructions to perform the forwarding database lookup comprise further instructions that cause the machine to directly access a forwarding table in hardware.

9. The Non-transitory machine accessible storage medium of claim 6, wherein the instructions to perform the forwarding database lookup comprise further instructions that cause the machine to access a software forwarding table.

10. The Non-transitory machine accessible storage medium of claim 7, comprising further instructions that cause the machine to:

set a bit in the port array corresponding to a Link Aggregation port when the Link Aggregation port is operational; and

reset the bit in the port array corresponding to the port when the Link Aggregation port is not operational.

11. A network switch, comprising:

at least one port to receive a data packet, the packet having a destination address that is reached via a Link Aggregation group on a virtual local area network (VLAN);

a memory to store a forwarding database; and

a processor to perform a forwarding database lookup to determine a Link Aggregation port reference number for the data packet on the VLAN;

the processor further to search a Link Aggregation port table to determine a primary Link Aggregation port and a backup Link Aggregation port for forwarding the packet based at least on the Link Aggregation port reference number;

the processor further to search a port array to determine if the primary Link Aggregation port is valid;

a forwarding module to forward the packet on the primary Link Aggregation port if the primary port is valid; and

the forwarding module to forward the packet on the backup Link Aggregation port if the primary port is not valid.

12. The system of claim 11, wherein each Link Aggregation port in the port array is represented by 1 bit.

13. The system of claim 11, wherein the processor further comprises a direct memory access interface to directly access the forwarding database in memory.

14. The system of claim 12, further comprising:

a port status module to determine an operational status of a Link Aggregation port;

the port status module to set a bit in the port array corresponding to a Link Aggregation port when the Link Aggregation port is operational; and

the port status module to reset the bit in the port array corresponding to the port when the Link Aggregation port is not operational.