Transparent network connection takeover

• US 7,996,517 B2
• Filed: 07/10/2006
• Issued: 08/09/2011
• Est. Priority Date: 01/23/2002
• Status: Expired due to Fees

• Current Assignee: Micro Focus Software, Inc. (Open Text Corporation)
• Original Assignee: Novell Incorporated (Open Text Corporation)
• Inventors: Davis, Howard Rollin, Carter, Stephen R.
• Primary Examiner(s): Chang; Jungwon
• Application Number:
  US11/483,811
• Publication Number:
  US 20060253575A1
• Time in Patent Office: 1,856 Days
• Field of Search: 709/227, 709/224, 714/1, 714/4.11
• US Class Current: 709/224
• CPC Class Codes: G06F 11/203 using migration
• CPC Class Codes: G06F 15/173 using an interconnection network, e.g. matrix, shuffle, pyramid, star, snowflake
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1034 Reaction to server failures by a load balancer
• 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 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06

Abstract

Techniques for the transparent takeover of network connections are presented. A first server is engaged in a connection with a client. The transactions of the connection and the traffic are monitored by a traffic cache manager. The first server records sequence numbers for the transactions with a synchronization store. If the first server fails, a last recorded sequence number is updated by the traffic cache manager within the synchronization store on behalf of a second server, which is to takeover the connection for the unresponsive first server.

Claims

1. A method, comprising:

monitoring, over a network on a front-end of a first server, a connection between the first server and a client;

detecting that the first server is unresponsive, the detection is made when a second server that is trying to take over for the first server makes a request for a current sequence number for transactions occurring between the client and the first server; and

updating a database when a last recorded sequence number in a synchronization store is less than the current sequence number associated with a last transaction.

2. The method of claim 1, wherein monitoring further includes recording acknowledgment identifiers for transactions which are sent by the first server to the client.

3. The method of claim 2, wherein monitoring further includes intercepting the acknowledgement identifiers as they are being sent to the client from the first server over the front-end, wherein the front-end includes a network interface device that is least one of a network router, a network bridge, and a network switch.

4. The method of claim 1, wherein detecting further includes receiving the current sequence number from a failover service associated with the database when the first server is unresponsive for purposes of moving the connection to the second server.

5. The method of claim 1, wherein detecting further includes receiving the current sequence number from the second server that is taking over the connection for the first server.

6. The method of claim 1, wherein updating further includes accessing the database from both memory and storage.

7. The method of claim 1, wherein updating further includes interacting with a failover service to update the database.

8. A method, comprising:

monitoring transactions for a connection between a first server and a client over a first network; and

interacting with the first server and a second server over a second network to supply the second server with a current sequence number for the transactions of the connection when the first server becomes unresponsive and the second server is taking over the connection, the second network is separate and independent from the first network, and the second server consults a synchronization store for purposes of determining whether a last recorded sequence number for a particular transaction or a particular acknowledgment noted by the first server is available from the synchronization store, the first server is noticed as having failed when the second server makes a request for a current transaction number for the transactions.

9. The method of claim 8 further comprising, supplying the current sequence number in response to the second server providing the last recorded sequence number that the second server acquired from the shared connection store.

10. The method of claim 8, wherein monitoring further includes intercepting the transactions received over the first network from a network switch.

11. The method of claim 10, wherein monitoring further includes forwarding the transactions to the first server.

12. The method of claim 8, wherein monitoring further includes caching the transactions.

13. The method of claim 8, wherein interacting further includes using the second network as a connection to the first and second servers that does not process the transactions.

14. The method of claim 13, wherein interacting further includes using the second network as local bus connections to the first and second servers.

15. A system, comprising:

a synchronization store; and

a traffic cache manager, the synchronization store records sequence numbers for transactions occurring with a connection between a first server and a client over a network as communicated by the first server to the synchronization store, and the traffic cache manager is to independently cache the transactions from a network switch before the first server receives the transactions, and the traffic cache manager is to update the sequence numbers and the transactions when the first server fails and a second server takes over the connection, detection of the first server failing is noted when the second server that is taking over makes a request to the traffic cache manager for a current sequence number for the transactions.

16. The system of claim 15 further comprising, the network switch that routes the transactions to the first server.

17. The system of claim 16 further comprising, a router that interacts with the network switch and the Internet to communicate with the client.

18. The system of claim 15 further comprising, a failover service that maintains the synchronization store and that interacts with the traffic cache manager when the first server is unresponsive to update the sequence numbers and the transactions before the second server takes over the connection.

19. A system, comprising:

a first network;

a second network;

a synchronization store that a second server interrogates to acquire a last recorded sequence number when a first server becomes unresponsive; and

a traffic cache manager, wherein the first network is used for communicating transactions and traffic associated with an Internet connection between the first server and a client, and the second network is used for updating sequence numbers associated with the transactions when the first server becomes unresponsive to permit the second server to takeover the connection with the client, the second server does not include the Internet traffic between the first server and the client, and the traffic manager caches the transactions and the traffic from the first network and updates the sequence numbers of the transactions for the second server over the second network, the traffic cache manager becomes aware of the failing first server when the second server makes a request of the traffic cache manager for a current sequence number for the transactions.

20. The system of claim 19 further comprising, a network switch that forwards the transactions and the traffic to the traffic cache manager, and wherein the traffic cache manager forwards the transactions and the traffic to the first server.

21. The system of claim 19, wherein the first server is to record the sequence numbers for the transactions and the traffic in the synchronization store.

22. The system of claim 19, wherein the second network is local bus connections between the traffic manager and the first and second servers.

23. The system of claim 19, wherein the second network does not include communications associated with the transactions and the traffic.