Session-less load balancing of client traffic across servers in a server group

• US 8,553,537 B2
• Filed: 11/07/2008
• Issued: 10/08/2013
• Est. Priority Date: 11/09/2007
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Chao, Tienwei, Shao, Bill
• Primary Examiner(s): Rinehart, Mark
• Assistant Examiner(s): YEUNG, MANG HANG
• Application Number:
  US12/741,225
• Publication Number:
  US 20100265824A1
• Time in Patent Office: 1,796 Days
• Field of Search: 370229-235, 370/392, 370/465, 709219-235, 710/61
• US Class Current: 370/229
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways

Abstract

A switch device includes a packet forwarding table for providing load balancing across servers in a server group. Each table entry maps a hash value to a server in the server group. A hash value can be computed from the destination MAC address, destination IP address, and destination service port in the header of a received packet. The packet forwarding table is searched to find an entry with a hash value that matches the computed hash value and to identify the server to which the matching hash value maps. The switch device forwards the packet to the identified server. Implementing load-balancing decisions in hardware enables packet switching at the line rate of the switch ports. In addition, the hardware-based load balancing performed by the switch device eliminates session tables and the memory to store them, enabling the switch device to handle an unlimited number of client connections.

Claims

1. A method of forwarding incoming client traffic to servers in a group of servers, the method comprising:

receiving a packet from a client system, the packet including a packet header with a destination MAC (Media Access Control) address field, a destination IP (Internet Protocol) address field, and a destination service port field;

providing a single switch device with a single packet forwarding table for providing load balancing across servers in a server group, the packet forwarding table having a plurality of table entries, each table entry mapping a hash value to a server in a server group;

computing, by the single switch device, a hash value from a combination of data in the destination MAC address, destination IP address, and destination service port fields of the packet header of the received packet;

searching, by the single switch device, the single packet forwarding table to find a table entry with a hash value that matches the computed hash value and to identify, from the table entry, the server in the server group to which the matching hash value maps; and

forwarding sessionlessly, by the single switch device, the packet to the identified server.

2. The method of claim 1, wherein the server to which the identified table entry maps the computed hash value is a transparent proxy server.

3. The method of claim 1, wherein the server to which the identified table entry maps the computed hash value is an offloader proxy appliance.

4. The method of claim 1, wherein the server to which the identified table entry maps the computed hash value is a real server.

5. The method of claim 1, further comprising handling, by the single switch device, a number of connections with client systems unlimited by memory requirements for storing client traffic sessions.

6. The method of claim 1, further comprising switching, by the single switch device, incoming client traffic to the identified server at a 10 Gb line rate per port.

7. A method of forwarding incoming client traffic to servers in a group of servers, the method comprising:

providing a single switch device with a packet forwarding table for providing load balancing across servers in a server group, the packet forwarding table having a plurality of table entries, each table entry mapping a hash value to a server in the server group;

assigning a virtual IP address and a virtual MAC address to each real server in a real server group, wherein the assigned virtual IP address is the same virtual IP address for each real server in the real server group and the assigned virtual MAC address is the same virtual MAC address for each real server in the real server group;

receiving a packet from a client system addressed to the virtual IP address and the virtual MAC address;

computing, by the single switch device, a hash value from a source address in a packet header of the received packet;

searching, by the single switch device, the packet forwarding table to find a table entry with a hash value that matches the computed hash value and to identify, from the table entry, the server in the server group to which the matching hash value maps; and

forwarding sessionlessly, by the single switch device, the packet to the identified server.

8. The method of claim 7, further comprising intercepting and dropping, by the single switch device, advertisements of the virtual IP address issued by any of the real servers in the real server group.

9. The method of claim 7, further comprising intercepting, by the single switch device, requests from client systems to find a hardware address associated with a real server in the real server group and replying to the requests with the virtual IP address and the virtual MAC address.

10. The method of claim 7, further comprising advertising, by the single switch device, the virtual IP address to external devices.

11. The method of claim 7, further comprising configuring a network interface card of each real server in the real server group with the virtual IP address and a unique real server IP address.

12. The method of claim 7, wherein the server to which the identified table entry maps the computed hash value is a transparent proxy server.

13. The method of claim 7, wherein the server to which the identified table entry maps the computed hash value is an offloader proxy appliance.

14. The method of claim 7, wherein the server to which the identified table entry maps the computed hash value is a real server.

15. The method of claim 7, further comprising handling, by the single switch device, a number of connections with client systems unlimited by memory requirements for storing client traffic sessions.

16. The method of claim 7, further comprising switching, by the single switch device, incoming client traffic to the identified server at a 10 Gb line rate per port.

17. A switch device comprising:

first and second ports, a first port receiving a packet from a client system, the packet including a packet header with a destination MAC (Media Access Control) address field, a destination IP (Internet Protocol) address field, and a destination service port field;

a packet forwarding table for providing load balancing across servers in a server group, the packet forwarding table having a plurality of table entries, each table entry mapping a hash value to a server in the server group; and

a frame processor configured to compute a hash value from a combination of data in the destination MAC address, destination IP address, and destination service port fields of the packet header of the received packet, search the packet forwarding table to find a table entry with a hash value that matches the computed hash value and to identify the server in the server group to which the matching hash value maps, and forward sessionlessly the packet through the second port to the identified server in the server group.

18. The switch device of claim 17, wherein the server to which the identified table entry maps the computed hash value is a transparent proxy server of in transparent proxy server group.

19. The switch device of claim 17, wherein the server to which the identified table entry maps the computed hash value is an offloader proxy appliance in an offloader proxy appliance group.

20. The switch device of claim 17, wherein the server to which the identified table entry maps the computed hash value is a real server in a real server group.

21. The switch device of claim 17, wherein the switch device is capable of handling number of connections with client systems without limit because of memory requirements for storing client traffic sessions.

22. The switch device of claim 17, wherein each port operates at a line rate of at least as fast as 10 Gb, and the switch device switches the packet received at the first port for forwarding to the identified server through the second port at the 10 Gb line rate per port.

23. The switch device of claim 17, wherein the switch device further comprises a management processor for checking a health status of each server in the server group.

24. The switch device of claim 23, wherein the management processor removes a server from the packet forwarding table if the server fails a health status check.

25. A switch device, comprising:

first and second ports, a first port receiving a packet from a client system addressed to a virtual IP address and a virtual MAC address, the virtual IP address and the virtual MAC address being assigned to each real server in a real server group with which the switch device is in communication, the assigned virtual IP address being the same virtual IP address for each real server in the real server group and the assigned virtual MAC address being the same virtual MAC address for each real server in the real server group;

a packet forwarding table for providing load balancing across servers in a server group, the packet forwarding table having a plurality of table entries, each table entry mapping a hash value to a server in a server group; and

a frame processor configured to compute a hash value from a source address in a packet header of the received packet, search the packet forwarding table to find a table entry with a hash value that matches the computed hash value and to identify the server in the server group to which the matching hash value maps, and forward sessionlessly the packet through the second port to the identified server in the server group.

26. The switch device of claim 25, wherein the switch device is configured to intercept and drops advertisements of the virtual IP address issued by any of the real servers in the real server group.

27. The switch device of claim 25, wherein the switch device is configured to intercept requests from client systems to find a hardware address associated with a real server in the real server group and replies to the requests with the virtual IP address and the virtual MAC address.

28. The switch device of claim 25, wherein the switch device is configured to advertise the virtual IP address to client systems.

29. The switch device of claim 25, wherein each real server in the real server group has a network interface card configured with the virtual IP address and a unique real server IP address.

30. The switch device of claim 25, wherein the server to which the identified table entry maps the computed hash value is a transparent proxy server of in transparent proxy server group.

31. The switch device of claim 25, wherein the server to which the identified table entry maps the computed hash value is an offloader proxy appliance in an offloader proxy appliance group.

32. The switch device of claim 25, wherein the server to which the identified table entry maps the computed hash value is a real server in a real server group.

33. The switch device of claim 25, wherein the switch device is capable of handling number of connections with client systems without limit because of memory requirements for storing client traffic sessions.

34. The switch device of claim 25, wherein each port of the switch device operates at a line rate of at least as fast as 10 Gb, and the switch device switches the packet received at the first port for forwarding sessionlessly to the identified server through the second port at the 10 Gb line rate per port.

35. The switch device of claim 25, wherein the switch device further comprises a management processor for checking a health status of each server in the server group.

36. The switch device of claim 35, wherein the management processor removes a given server from the packet forwarding table if the given server fails a health status check.