Load balance device and method for packet switching

• US 20030063594A1
• Filed: 08/09/2002
• Published: 04/03/2003
• Est. Priority Date: 08/13/2001
• Status: Active Grant

• Current Assignee: VIA Technologies Incorporated (VIA Technologies)
• Original Assignee: VIA Technologies Incorporated (VIA Technologies)
• Inventors: Li, Chin-Chang, Shih, Saten
• Granted Patent: US 7,230,925 B2
• Time in Patent Office: Days
• US Class Current: 370/342
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/11 Identifying congestion
• CPC Class Codes: H04L 47/125 by balancing the load, e.g. traffic engineering
• CPC Class Codes: H04L 47/43 Assembling or disassembling of packets, e.g. segmentation and reassembly [SAR]

Abstract

The invention discloses a packet switching load balance device and method. In a trunking-port network environment, a ticket assigner and a ticket distributor together achieve the output load balance during the transmission process of packet switching. The ticket assigner assigns one of tickets to a packet received by a logical port, and the ticket distributor determines which one of the physical output ports to transmit the packet according to the assigned ticket. In the transmission process, a load monitor dynamically adjusts the ticket distribution scheme used for the ticket distributor, thus the load balance is optimized.

Claims

1. A load balance device for a logical port containing a plurality of physical output ports, the load balance device comprising:

a ticket assigner, which assigns one of a plurality of tickets to a packet received by the logical port;

a ticket distributor, which determines a transmission route according to the assigned ticket so that the packet is transmitted through one of the physical output ports; and

a load monitor, which monitors a plurality of loads associated with the tickets.

2. The load balance device of claim 1, wherein the ticket assigner extracts partial bits of a source address and a destination address of the packet to perform a logical operation, in order to generate a result as the ticket of the packet.

3. The load balance device of claim 2, wherein the ticket assigner extracts a plurality of bits of the source address and a plurality of bits of the destination address of the packet according to a number of the physical output ports.

4. The load balance device of claim 3, wherein the ticket assigner performs an XOR operation on the extracted bits to obtain the result as the ticket of the packet.

5. The load balance device of claim 4, wherein the load monitor accumulates a plurality of total packet lengths associated with the tickets during a fixed period as the loads respectively.

6. The load balance device of claim 5, wherein the load monitor determines the transmission route according to the loads so that the plurality of physical output ports achieves load balance.

7. A load balance device for a logical port containing a plurality of physical output ports, the load balance device comprising:

a ticket assigner to assign one of a plurality of tickets to a packet received by the logical port, the assigned ticket is obtained from a logical operation of partial bits extracted from a source address and a destination address of the packet; and

a ticket distributor to determine which one of the physical output ports to transmit the packet according to the assigned ticket.

8. The load balance device of claim 7, wherein the ticket assigner extracts the last three bits of the source address and the destination address of the packet.

9. The load balance device of claim 8, wherein the ticket assigner performs an XOR operation on the extracted bits.

10. The load balance device of claim 9, wherein the load of the ticket is an accumulated packet length associated with the ticket.

11. A load balance method for the packet switching, comprising the steps of:

assigning a plurality of tickets to a plurality of packets to be transmitted, each ticket is obtained by a logical operation of a plurality of bits extracted from a source address and a destination address of each packet;

accumulating a plurality of total packet lengths associated with the tickets during a first predetermined period;

distributing the tickets to a plurality of physical output ports during a second predetermined period according to the accumulated packet lengths associated

with the tickets accumulated during said first predetermined period; and

transmitting each packet through a corresponding physical output port according to the associated ticket.

12. The method of claim 11, wherein the assigning step includes a step of extracting the last three bits of the source address and the last three bits of the destination address to perform an XOR operation.

13. The method of claim 11, wherein the distributing step includes a step of evaluating a plurality of schemes for distributing said tickets to the physical output ports so as to balance the load for the physical output ports.

14. The method of claim 13, wherein one of the schemes includes a steps of assigning the tickets progressively in order according to the accumulated packet lengths to the physical output ports.

15. The method of claim 13, wherein one of the schemes includes the steps of:

computing an average load of all tickets; and

assigning said tickets progressively in order, for each physical output port, according to the accumulated packet lengths to said each physical output port till a load sum for said each physical output port exceeds the average load.