Reallocating address spaces of a plurality of servers using a load balancing policy and a multicast channel

• US 6,718,387 B1
• Filed: 12/10/1997
• Issued: 04/06/2004
• Est. Priority Date: 12/10/1997
• Status: Expired due to Term

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: Rom, Raphael, Gupta, Amit
• Primary Examiner(s): Wiley, David
• Assistant Examiner(s): Vaughn, Jr., William C.
• Application Number:
  US08/988,205
• Time in Patent Office: 2,309 Days
• Field of Search: 709/256, 709/215, 709/240, 709/236, 709/229, 709/225, 709/226, 709/105, 370/409, 370/230, 370/352, 370/390, 370/392, 370/397, 370/399, 370/432, 370/474
• US Class Current: 709/226
• CPC Class Codes: H04L 63/0442 wherein the sending and receiving network entities apply asymmetric encryption, i.e. different keys for encryption and decryption cryptographic mechanisms or cryptographic arrangements for public-key encryption H04L9/30
• CPC Class Codes: H04L 63/065 for group communications cryptographic mechanisms or cryptographic arrangements for key management involving conference or group key H04L9/0833
• CPC Class Codes: H04L 63/0823 using certificates cryptographic mechanisms or cryptographic arrangements for entity authentication involving certificates H04L9/3263
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1006 with static server selection, e.g. the same server being selected for a specific client
• CPC Class Codes: H04L 67/1012 based on compliance of requirements or conditions with available server resources
• CPC Class Codes: H04L 67/1023 based on a hash applied to IP addresses or costs
• CPC Class Codes: H04L 67/1025 Dynamic adaptation of the criteria on which the server selection is based
• 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 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 9/40 Network security protocols

Abstract

A method for load balancing including creating a network, having a plurality of servers, to service a single multicast address using a source specific join, where the source specific join allows each of the plurality of servers to specify a source internet protocol address range that each of the plurality of servers services. Further, method includes reallocating the source internet protocol address range specified for at least one of the plurality of servers using a load balancing policy and a control multicast channel while at least one of the plurality of servers is handling communications.

Claims

1. A method for load balancing comprising:

creating a network to service a single multicast address comprising a plurality of servers using a source specific join, wherein said source specific join allows each of said plurality of servers to specify a source internet protocol address range that each of said plurality of servers services; and

reallocating said source internet protocol address range specified for at least one of said plurality of servers using a load balancing policy and a control multicast channel while said at least one of said plurality of servers is handling communications.

2. The method of claim 1, wherein said source internet protocol address range is reallocated for at least one of said plurality of servers using at least one selected from said group consisting of a source specific leave and said source specific join.

3. The method of claim 1 wherein said load balancing policy comprises:

sending a SYN packet for a TCP connection from a user to a first one of said plurality of servers including a tag and a cookie; and

sending a SYN-ACK packet from said first one of said plurality of servers to said user including a tag, cookie and destination information.

4. The method of claim 3, wherein said load balancing policy further comprises re-directing a connection from said first one of said plurality of servers to a second one of said plurality of servers by sending a packet from said second one of said plurality of servers to said user containing said tag, said cookie and new destination information.

5. A method of allocating communications to a plurality of servers, comprising:

directing all communications to be handled by said plurality of servers to a multicast address, and

causing said plurality of servers to listen to packets originating a different source internet protocol address range,

wherein said different source internet protocol address range assigned to one of said plurality of servers may be reallocated to carry out a load balancing policy using a multicast control.

6. The method of claim 5 wherein, when a packet is received at one of said plurality of servers over a user connection originating from a source internet protocol address in said source internet protocol address range previously serviced by a different member of said plurality of servers but now serviced by said one of said plurality of servers, said one of said plurality of servers causes disconnection of said user connection.

7. The method of claim 5 wherein, when a packet is received at one of said plurality of servers from a user having a source internet protocol address in said source internet protocol address range not previously serviced by said one of said plurality of servers but which is currently serviced by said one of said plurality of servers, said one of said plurality of servers forwards that packet over said control multicast channel to said plurality of servers.

8. The method of claim 7 wherein, said one of said plurality of servers previously handling said user processes said packet received over said control multicast channel.

9. The method of claim 7 wherein, said one of said plurality of servers previously handling said user notifies said one of said plurality of servers currently servicing said user to forward future packets over a point to point connection.

10. The method of claim 5 wherein, when a packet is received at one of said plurality of servers from a user having a source internet protocol address in said source internet protocol address range not previously serviced by said one of said plurality of servers but which is currently serviced by said one of said plurality of servers and for which said one of said plurality of servers does not have current state information, said one of said plurality of servers requests state information over said control multicast channel.

11. The method of claim 10 wherein, said one of said plurality of servers processes said packet in accordance with state information received over said control multicast channel.

12. A computer network, comprising:

at least one user device connected to said network and sending information to a multicast address; and

a plurality of servers connected to said network and configured to receive multicast packets only from users having source addresses from at least one source internet protocol address range using a load balancing policy and a control multicast channel,

wherein said source internet protocol address range specified for at least one of said plurality of serves is reallocated using the control multicast channel while said at least one of said plurality of servers is handling communications.

13. The network of claim 12 wherein, said source internet address protocol address range assigned to a particular server changes in accordance with a load balancing policy.

14. The network of claim 13 wherein, existing connections are handled when a connection from one source internet address protocol range is transferred to from a first member of said plurality of servers to a second member of said plurality of servers.