Decrypting load balancing array system

• US 20010034792A1
• Filed: 02/07/2001
• Published: 10/25/2001
• Est. Priority Date: 03/10/2000
• Status: Active Grant

• Current Assignee: Akamai Technologies, Inc.
• Original Assignee: Akamai Technologies, Inc.
• Inventors: Swildens, Eric Sven-Johan
• Granted Patent: US 7,340,532 B2
• Time in Patent Office: Days
• US Class Current: 709/238
• CPC Class Codes: H04L 63/0471 applying encryption by an intermediary, e.g. receiving clear information at the intermediary and encrypting the received information at the intermediary before forwarding
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/10015 Access to distributed or replicated servers, e.g. using brokers
• CPC Class Codes: H04L 67/1008 based on parameters of servers, e.g. available memory or workload monitoring of computer activity G06F11/30
• CPC Class Codes: H04L 67/1023 based on a hash applied to IP addresses or costs
• CPC Class Codes: H04L 67/1027 Persistence of sessions during load balancing
• CPC Class Codes: H04L 67/1034 Reaction to server failures by a load balancer
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A decrypting load balancing array system uses a Pentaflow approach to network traffic management that extends across an array of Decrypting Load Balancing Array (DLBA) servers sitting in front of back end Web servers. One of the DLBA servers acts as a scheduler for the array through which all incoming requests are routed. The scheduler routes and load balances the traffic to the other DLBA servers (including itself) in the array. Each DLBA server routes and load balances the incoming request packets to the appropriate back end Web servers. Responses to the requests from the back end Web servers are sent back to the DLBA server which forwards the response directly to the requesting client. SSL packets are decrypted in the DLBA server before being routed to a back end Web server, allowing the DLBA server to schedule SSL sessions to back end Web servers based on a cookie or session ID. Response packets are encrypted by the DLBA server before being forwarded to the client. The invention also uses cookie injection to map a client to a specific back end Web server. In addition, any DLBA server in the array is capable of taking over the scheduler functionality in case of scheduler failure. URL based scheduling and hash scheduling of request packets with keepalive connections is easily performed due to the invention'"'"'s architecture.

Claims

1. A process for routing packets through a load balancing array of servers across a network in a computer environment, comprising the steps of:

providing a plurality of load balancing servers;

providing at least one back end Web server;

wherein one of said load balancing servers is also a scheduler;

wherein a request packet from a client is routed through said scheduler;

wherein said scheduler routes and load balances said request packet to a load balancing server;

wherein said load balancing server routes and load balances said request packet to a back end Web server;

wherein said back end Web server'"'"'s response packet to said request packet is sent to said load balancing server; and

wherein said load balancing server sends said response packet directly to said client.

2. The process of

claim 1

, wherein said scheduler routes and load balances client requests to itself.

3. The process of

claim 1

, further comprising the steps of:

detecting the failure of said scheduler; and

electing one of said load balancing servers as the new scheduler.

4. The process of

claim 1

, wherein said scheduler detects the failure of other load balancing servers;

and wherein said scheduler stops routing packets to any failed load balancing servers.

5. The process of

claim 1

, wherein said load balancing server schedules sessions to back end Web servers based on a cookie or session ID.

6. The process of

claim 1

, wherein said load balancing server uses cookie injection to map a client to a specific back end Web server.

7. The process of

claim 1

, wherein said load balancing server decrypts said request packet if it is an SSL session before routing and load balancing said request packet to a back end Web server.

8. The process of

claim 7

, wherein said load balancing server encrypts said response packet if it is an SSL session before sending said response packet directly to said client.

9. The process of

claim 1

, wherein said load balancing server establishes a connection with said client and said client keeps said connection alive with said load balancing server.

10. The process of

claim 9

, wherein said load balancing server performs URL based scheduling of request packets.

11. The process of

claim 9

, wherein said load balancing server performs hash scheduling of request packets.

12. The process of

claim 1

, wherein said load balancing server maintains persistent connections in all its paths when required;

and wherein said load balancing server uses hash group based persistence to maintain its persistence tables.

13. The process of

claim 1

, wherein said load balancing server detects if a back end Web server fails;

and wherein said load balancing server stops routing request packets to failed back end Web servers.

14. The process of

claim 1

, further comprising the step of:

providing a content delivery network; and

wherein said load balancing server modifies select URLs in the HTML page in said response packet to serve them from said content delivery network.

15. The process of

claim 14

, wherein HTML pages that have modified URLs are cached to improve performance.

16. An apparatus for routing packets through a load balancing array of servers across a network in a computer environment, comprising:

a plurality of load balancing servers;

at least one back end Web server;

wherein one of said load balancing servers is also a scheduler;

wherein a request packet from a client is routed through said scheduler;

wherein said scheduler routes and load balances said request packet to a load balancing server;

wherein said load balancing server routes and load balances said request packet to a back end Web server;

wherein said back end Web server'"'"'s response packet to said request packet is sent to said load balancing server; and

wherein said load balancing server sends said response packet directly to said client.

17. The apparatus of

claim 16

, wherein said scheduler routes and load balances client requests to itself.

18. The apparatus of

claim 16

, further comprising:

a module for detecting the failure of said scheduler; and

a module for electing one of said load balancing servers as the new scheduler.

19. The apparatus of

claim 16

, wherein said scheduler detects the failure of other load balancing servers;

and wherein said scheduler stops routing packets to any failed load balancing servers.

20. The apparatus of

claim 16

, wherein said load balancing server schedules sessions to back end Web servers based on a cookie or session ID.

21. The apparatus of

claim 16

, wherein said load balancing server uses cookie injection to map a client to a specific back end Web server.

22. The apparatus of

claim 16

, wherein said load balancing server decrypts said request packet it it is an SSL session before routing and load balancing said request packet to a back end Web server.

23. The apparatus of

claim 22

, wherein said load balancing server encrypts said response packet if it is an SSL session before sending said response packet directly to said client.

24. The apparatus of

claim 16

, wherein said load balancing server establishes a connection with said client and said client keeps said connection alive with said load balancing server.

25. The apparatus of

claim 24

, wherein said load balancing server performs URL based scheduling of request packets.

26. The apparatus of

claim 24

, wherein said load balancing server performs hash scheduling of request packets.

27. The apparatus of

claim 16

, wherein said load balancing server maintains persistent connections in all its paths when required;

and wherein said load balancing server uses hash group based persistence to maintain its persistence tables.

28. The apparatus of

claim 16

, wherein said load balancing server detects if a back end Web server fails;

and wherein said load balancing server stops routing request packets to failed back end Web servers.

29. The apparatus of

claim 16

, further comprising:

a content delivery network; and

wherein said load balancing server modifies select URLs in the HTML page in said response packet to serve them from said content delivery network.

30. The apparatus of

claim 29

, wherein HTML pages that have modified URLs are cached to improve performance.