System and method for knowledgeable node initiated TCP splicing

• US 7,000,027 B2
• Filed: 11/29/2001
• Issued: 02/14/2006
• Est. Priority Date: 11/29/2001
• Status: Expired due to Term

• Current Assignee: Twitter Inc (X Holdings Corp.)
• Original Assignee: International Business Machines Corporation
• Inventors: Hensbergen, Eric Van
• Primary Examiner(s): Burgess, Glenton B.
• Assistant Examiner(s): STRANGE, AARON N
• Application Number:
  US09/998,048
• Publication Number:
  US 20030101273A1
• Time in Patent Office: 1,538 Days
• Field of Search: 709227-229, 709238-239, 709/242
• US Class Current: 709/239
• 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 67/1017 based on a round robin mechanism
• CPC Class Codes: H04L 67/563 Data redirection of data network streams
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/161 Implementation details of TCP/IP or UDP/IP stack architecture; Specification of modified or new header fields
• CPC Class Codes: H04L 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A system and method utilizes back-end nodes to determine which node should handle an incoming requests and then utilizes the front-end switch to splice one or more connections between the client and the chosen node. Chosen nodes can repeatedly handoff the connection to other nodes to handle the client'"'"'s requests. The front-end switch provides the initial client connection to back-end nodes in a round-robin approach distributing initial connections among the back-end nodes. A proxy application on the back-end node accepts the connection, parses the request, and determines which back-end node should handle the request. If another back-end node should handle the request, the back-end node currently connected to the client performs a handoff to the target back-end node. The switch splices the initial connection to a connection to the selected node and modifies subsequent packet headers appropriately in order to map the two connection states to one another.

Claims

1. A method for splicing network connections, said method comprising:

receiving a first handoff request from a first node corresponding to a first node identifier, wherein the first node is connected to a client node using a first connection;

identifying a second node based on a second node identifier, wherein the second node is connected to the first node using a second connection;

updating one or more connection tables with data corresponding to the first and second connections, wherein the connection tables include a first mapping table and a reverse mapping table;

redirecting one or more client packets sent over the first connection from the client node to the second node in response to the updated connection tables;

writing a first reverse mapping entry to the first mapping table, the first reverse mapping entry including the second node identifier, the first node identifier and a pointer to the reverse mapping table; and

writing a second reverse mapping entry in the reverse mapping table, the reverse mapping entry including the client node identifier.

2. The method as described in claim 1 wherein the updating further comprises:

writing a first entry to the first mapping table, the first entry including the client node identifier, the first node identifier, and a pointer to a second mapping table;

creating the second mapping table; and

writing a second entry in the second mapping table, the second entry including the second node identifier.

3. The method as described in claim 2 further comprising:

writing a third entry in the second mapping table in response to receiving a second handoff request, the third entry identifying a third node, wherein the second entry includes a first handoff sequence value corresponding to the first handoff request and wherein the third entry includes a second handoff sequence value corresponding to the second handoff request;

receiving a request from the client, the request including a request sequence value corresponding to the request; and

redirecting the request to the third node in response to the request sequence value being greater than or equal to the second handoff sequence value.

4. The method as described in claim 3 further comprising:

redirecting the request to the second node in response to the request sequence value being greater than or equal to the first handoff sequence value and less than the second handoff sequence value.

5. The method as described in claim 1 further comprising:

receiving a packet from the second node that includes a destination address identifying the first node;

matching the packet to the first reverse mapping entry;

retrieving the client node identifier from the reverse mapping table in response to the matching; and

changing the destination address to identify the client node identifier.

6. The method as described in claim 1 further comprising:

redirecting one or more response packets sent by the second node over the second connection to the client node in response to the updated tables.

18. The method as described in claim 1 further comprising:

recording a sequence range corresponding to the first handoff request;

receiving a packet from the client node, the packet including a sequence value;

performing the redirecting only if the packet'"'"'s sequence value is within the sequence range.

7. An information handling system comprising:

one or more processors;

a memory accessible by the processors;

a network interface connecting the information handling system to a computer network; and

a connection splicing tool for splicing connections between nodes, the connection splicing tool including;

means for receiving a first handoff request from a first node, wherein the first node is connected to a client node using a first connection over the computer network;

means for identifying a second node based on a second node identifier, wherein the second node is connected to the first node using a second connection over the computer network;

means for updating one or more connection tables with data corresponding to the first and second connections, wherein the connection tables include a first mapping table and a reverse mapping table;

means for redirecting one or more client packets sent over the first connection from the client node to the second node in response to the updated connection tables;

means for writing a first reverse mapping entry to the first mapping table, the first reverse mapping entry including the second node identifier, the first node identifier and a pointer to the reverse mapping table; and

means for writing a second reverse mapping entry in the reverse mapping table, the reverse mapping entry including the client node identifier.

8. The information handling system as described in claim 7 wherein the means for updating further comprises:

means for writing a first entry to the first mapping table stored in the memory, the first entry including the client node identifier, the first node identifier, and a pointer to a second mapping table stored in the memory;

means for creating the second mapping table; and

means for writing a second entry in the second mapping table, the second entry including the second node identifier.

11. The information handling system as described in claim 7 further comprising:

means for receiving a packet from the second node over the computer network, the packet including a destination address identifying the first node;

means for matching the packet to the first reverse mapping entry;

means for retrieving the client node identifier from the reverse mapping table in response to the matching; and

means for changing the destination address to identify the client node identifier.

12. The information handling system as described in claim 7 further comprising:

means for redirecting one or more response packets sent by the second node over the second connection to the client node in response to the updated tables.

19. The information handling system as described in claim 7 further comprising:

means for recording a sequence range corresponding to the first handoff request;

means for receiving a packet from the client node, the packet including a sequence value;

means for performing the redirecting only if the packet'"'"'s sequence value is within the sequence range.

9. The information handling system as described in claim 9 further comprising:

means for writing a third entry in the second mapping table in response to receiving a second handoff request, the third entry identifying a third node connected to the computer network, wherein the second entry includes a first handoff sequence value corresponding to the first handoff request and wherein the third entry includes a second handoff sequence value corresponding to the second handoff request;

means for receiving a request from the client over the computer network, the request including a request sequence value corresponding to the request; and

means for redirecting the request to the third node in response to the request sequence value being greater than or equal to the second handoff sequence value.

10. The information handling system as described in claim 9 further comprising:

means for redirecting the request to the second node in response to the request sequence value being greater than or equal to the first handoff sequence value and less than the second handoff sequence value.

13. A computer program product stored in a computer operable media for splicing network connections, said computer program product comprising:

means for receiving a first handoff request from a first node, wherein the first node is connected to a client node using a first connection;

means for identifying a second node based on a second node identifier, wherein the second node is connected to the first node using a second connection;

means for updating one or more connection tables with data corresponding to the first and second connections, wherein the connection tables include a first mapping table and a reverse mapping table;

means for redirecting one or more client packets sent over the first connection from the client node to the second node in response to the updated connection tables;

means for writing a first reverse mapping entry to the first mapping table, the first reverse mapping entry including the second node identifier, the first node identifier and a pointer to the reverse mapping table; and

means for writing a second reverse mapping entry in the reverse mapping table, the reverse mapping entry including the client node identifier.

14. The computer program product as described in claim 13 wherein the means for updating further comprises:

means for writing a first entry to the first mapping table, the first entry including the client node identifier, the first node identifier, and a pointer to a second mapping table;

means for creating the second mapping table; and

means for writing a second entry in the second mapping table, the second entry including the second node identifier.

15. The computer program product as described in claim 14 further comprising:

means for writing a third entry in the second mapping table in response to receiving a second handoff request, the third entry identifying a third node, wherein the second entry includes a first handoff sequence value corresponding to the first handoff request and wherein the third entry includes a second handoff sequence value corresponding to the second handoff request;

means for receiving a request from the client, the request including a request sequence value corresponding to the request; and

means for redirecting the request to the third node in response to the request sequence value being greater than or equal to the second handoff sequence value.

16. The computer program product as described in claim 15 further comprising:

means for redirecting the request to the second node in response to the request sequence value being greater than or equal to the first handoff sequence value and less than the second handoff sequence value.

17. The computer program product as described in claim 13 further comprising:

means for receiving a packet from the second node that includes a destination address identifying the first node;

means for matching the packet to the first reverse mapping entry;

means for retrieving the client node identifier from the reverse mapping table in response to the matching; and

means for changing the destination address to identify the client node identifier.

20. The computer program product as described in claim 13 further comprising:

means for recording a sequence range corresponding to the first handoff request;

means for receiving a packet from the client node, the packet including a sequence value;

means for performing the redirecting only if the packet'"'"'s sequence value is within the sequence range.