Interleaved processing of dropped packets in a network device

• US 20070104211A1
• Filed: 11/13/2006
• Published: 05/10/2007
• Est. Priority Date: 11/10/2005
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Opsasnick, Eugene
• Granted Patent: US 8,218,546 B2
• Time in Patent Office: Days
• US Class Current: 370/412
• CPC Class Codes: H04L 45/7453 using hashing
• CPC Class Codes: H04L 47/521 Static queue service slot or fixed bandwidth allocation
• CPC Class Codes: H04L 47/564 Attaching a deadline to packets, e.g. earliest due date first
• CPC Class Codes: H04L 47/58 Changing or combining different scheduling modes, e.g. multimode scheduling
• CPC Class Codes: H04L 47/6215 Individual queue per QOS, rate or priority
• CPC Class Codes: H04L 47/6225 Fixed service order, e.g. Round Robin
• CPC Class Codes: H04L 47/623 Weighted service order
• CPC Class Codes: H04L 47/6285 Provisions for avoiding starvation of low priority queues
• CPC Class Codes: H04L 49/3027 Output queuing

Abstract

A network device for processing packets includes at least one ingress module for performing switching functions on a packet, a memory management unit for storing the packet and at least one egress module for transmitting the packet to at least one port. The at least one egress module is configured to maintain multiple queues for the at least one port, including a purge queue, and to store the packet in the purge queue when an error condition is determined when the end of the packet is received by the at least one ingress module.

Claims

1. A network device for processing packets, the network device comprising:

at least one ingress module for performing switching functions on a packet;

a memory management unit for storing the packet; and

at least one egress module for transmitting the packet to at least one port;

wherein the at least one egress module is configured to maintain multiple queues for the at least one port, including a purge queue, and to store the packet in the purge queue when an error condition is determined when the end of the packet is received by the at least one ingress module.

2. The network device according to claim 1, wherein the at least one ingress module is configured to divide the packet into cells and at least some of the cells are stored in the purge queue when the error condition is determined.

3. The network device according to claim 2, wherein the at least one egress port is configured to store cells from a middle or an end of the packet in the purge queue when the error condition is determined.

4. The network device according to claim 2, wherein the memory management unit is configured to return the cells to a free pool memory and to update counters related to memory use.

5. The network device according to claim 1, wherein the at least one egress module is configured to maintain the multiple queues based on classes of service assigned to packets received by the network device.

6. The network device according to claim 1, wherein the at least one egress module is configured to store the packet in the purge queue when Cyclic Redundancy Check (CRC) or Maximum Transmission Unit (MTU) error condition is determined when the end of the packet is received by the at least one ingress module.

7. The network device according to claim 1, wherein the memory management unit is configured to not store remaining portions of the packet when the error condition is determined by the at least one ingress module.

8. A method for processing packets in a network device, the method comprising the steps of:

parsing a packet into cells;

determining an egress port for the packet;

storing at least one of the cells of the packet in a memory;

determining when an error condition exists when an end of the packet is received; and

forwarding the cells to a purge queue for an egress port when the error condition is determined to exist.

9. The method according to claim 8, wherein the step of forwarding the cells comprises storing cells from a middle or an end of the packet in the purge queue when the error condition is determined.

10. The method according to claim 9, further comprising returning the cells to a free pool memory and updating counters related to memory use.

11. The method according to claim 8, further comprising maintaining multiple queues on the egress port based on classes of service assigned to packets received by the network device.

12. The method according to claim 8, wherein the step of determining when an error condition exists comprises determining when Cyclic Redundancy Check (CRC) or Maximum Transmission Unit (MTU) error condition when the end of the packet is received.

13. The method according to claim 8, wherein the step of storing initial cells further comprises not storing remaining portions of the packet when the error condition is determined.

14. The method according to claim 8, further comprising setting a purge bit when the error condition is determined to exist.

15. An apparatus for processing packets in a network device, the apparatus comprising:

parsing means for parsing a packet into cells;

determining means for determining an egress port for the packet;

storing means storing the cells of the packet in a memory;

second determining means for determining when an error condition exists when an end of the packet is received; and

forwarding means for forwarding the cells to a purge queue for an egress port when the error condition is determined to exist by the second determining means.

16. The apparatus according to claim 15, wherein the storing means is configured to store cells from a middle or an end of the packet in the purge queue when the error condition is determined.

17. The apparatus according to claim 16, further comprising means for returning the cells to a free pool memory and updating counters related to memory use.

18. The apparatus according to claim 15, further comprising means for maintaining multiple queues on the egress port based on classes of service assigned to packets received by the network device.

19. The apparatus according to claim 15, wherein the second determining means is configured to determine when Cyclic Redundancy Check (CRC) or Maximum Transmission Unit (MTU) error condition exists when the end of the packet is received.

20. The apparatus according to claim 15, wherein the storing means is configured to not store remaining portions of the packet when the error condition is determined.