Bi-directional affinity within a load-balancing multi-node network interface

• US 20040003099A1
• Filed: 06/28/2002
• Published: 01/01/2004
• Est. Priority Date: 06/28/2002
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Joy, Joseph, House, Sean B., Dadhia, Rajesh
• Granted Patent: US 7,380,002 B2
• Time in Patent Office: Days
• US Class Current: 709/229
• 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 67/1023 based on a hash applied to IP addresses or costs

Abstract

A new network load balancing/firewall node for use in a system including multiple network load balancing/firewall nodes is disclosed. The network load balancing/firewall applies bi-directional load balancing affinity with regard to requests from external clients and corresponding responses from internal network servers. An external network load balancing adapter executes a load-balancing algorithm to determine whether a received client request is accepted by the network load balancing/firewall node. A firewall utility processes the received client request and maintains state information associated with the received client request. An internal network load balancing adapter ensures that the same network load balancing/firewall node accepts a response from an internal network server corresponding to the received client request.

Claims

1. A network load balancing/external network interface node, for use in a system including multiple network load balancing/external network interface nodes, including bi-directional load balancing affinity with regard to requests from external clients and corresponding responses from internal network servers, the network load balancing/external network interface comprising:

an external network load balancing adapter that executes a load-balancing algorithm to determine whether a received client request is accepted by the network load balancing/external network interface node;

an external network interface utility that processes the received client request and maintains state information associated with the received client request;

an internal network load balancing adapter that ensures the network load balancing/external network interface node accepts a response from an internal network server corresponding to the received client request, the internal network load balancing adapter comprising;

a complementary load-balancing algorithm to determine whether the received server response is accepted by the network load balancing/external network interface node, the complementary load-balancing algorithm rendering a same network load balancing/external network interface node selection as the received client request, and

a list of criteria for which the complementary load-balancing algorithm is selectively invoked.

2. The network load balancing/external network interface node of claim 1 wherein the load-balancing algorithm of the external network interface node includes as its input, an external address of a requesting client.

3. The network load balancing/external network interface node of claim 2 wherein the load-balancing algorithm of the external network interface node further includes as its input, a port identified in the request message.

4. The network load balancing/external network interface node of claim 1 wherein the list of criteria comprises a list of network server addresses.

5. The network load balancing/external network interface node of claim 4 wherein the list of network server addresses comprises an IP address uniquely identifying the internal network server.

6. The network load balancing/external network interface node of claim 1 wherein the list of criteria comprises a list of destination network MAC addresses.

7. The network load balancing/external network interface node of claim 4 wherein the list of internal network server addresses is provided to the internal network load balancing adapter by the external network interface utility.

8. The network load balancing/external network interface node of claim 1 wherein the external network interface utility is a firewall.

9. The network load balancing/external network interface node of claim 1 wherein the internal network load balancing adapter comprises a default load-balancing algorithm differing from the complementary load-balancing algorithm, and wherein the internal network load balancing adapter invokes the default load-balancing algorithm for messages containing the internal network source address that is not present on the list of criteria.

10. A network load-balancing/external network interface node, for use in a system including multiple network load-balancing/external network interface nodes, including bi-directional load-balancing affinity with regard to requests from external clients and corresponding responses from internal network servers, the network load-balancing/external network interface comprising:

an external network load-balancing adapter that executes a load-balancing algorithm to determine whether a received client request is accepted by the network load-balancing/external network interface node;

an external network interface utility that processes the received client request and maintains state information associated with the received client request;

an internal network load-balancing adapter that ensures the network load-balancing/external network interface node accepts a response from an internal network server corresponding to the received client request, the internal network load-balancing adapter comprising;

a complementary load-balancing algorithm to determine whether the received server response is accepted by the network load-balancing/external network interface node, the complementary load-balancing algorithm rendering a same network load-balancing/external network interface node selection as the received client request, and

an indicator set statically indicating that complementary load-balancing algorithm is selectively invoked.

11. The network load-balancing/external network interface node of claim 10 wherein the internal network load-balancing adapter comprises a default load-balancing algorithm differing from the complementary load-balancing algorithm, and wherein the internal network load-balancing adapter invokes the default load-balancing algorithm for messages containing the internal network source address that do not include the indicator.

12. The network load balancing/external network interface node of claim 10 wherein the indicator is set manually.

13. A method for establishing bi-directional affinity for a load balancing firewall comprising multiple load balancing/firewall nodes interposed between an internal network comprising multiple published servers that are identified within a list maintained by the load balancing/firewall node, and an external network comprising requesting clients, the method comprising:

first receiving, by an external network load balancing interface of the load balancing firewall, a request from an external client;

first determining, based upon a load-balancing algorithm, a selected load balancing/firewall node that processes the request from the external client;

establishing, by the selected load balancing/firewall node, a connection state corresponding to the request from the external client;

passing, by the selected load balancing/firewall node, the request from the external client to a selected one of the multiple published servers;

second receiving, by an internal network load balancing interface of the load balancing firewall, a message from the selected one of the multiple published servers;

second determining, in response to the second receiving step, whether the address of the selected one of the multiple published servers is present in the list of published servers; and

applying, by the internal network load balancing interface of the load balancing firewall, a complementary load-balancing algorithm to the message received during the second receiving step, in response to identifying the selected one of the multiple published servers within the list of published server during the second determining step, the complementary load-balancing algorithm determining the selected load balancing/firewall node established during the first determining step; and

processing, by the selected load balancing/firewall node, the message from the selected one of the multiple published servers.

14. The method for establishing bi-directional affinity for a load balancing firewall in claim 13 wherein the applying step further comprises the steps of:

applying, by the internal network load balancing interface of the load balancing firewall, a default load-balancing algorithm to the message received during the second receiving step, in response to not identifying the selected one of the multiple published servers within the list of published server during the second determining step, the default load-balancing algorithm differing from the complementary load-balancing algorithm.

15. The method for establishing bi-directional affinity for a load balancing firewall in claim 14 wherein the default algorithm is a modulo algorithm applied to a hash of the message received from the selected one of the multiple published servers.

16. The method for establishing bi-directional affinity for a load balancing firewall in claim 13 further comprising:

passing, by the selected load balancing/firewall node, the message from the selected one of the multiple published servers to the external client; and

receiving, by the external client, the message from the selected load balancing/firewall node.

17. The method for establishing bi-directional affinity for a load balancing firewall in claim 13 wherein the list of published servers comprises a list of IP addresses uniquely identifying the published servers.

18. A computer-readable medium having computer-executable components thereon for a load balancing firewall comprising multiple load balancing/firewall nodes interposed between an internal network comprising multiple published servers that are identified within a list maintained by the load balancing/firewall node, and an external network comprising requesting clients, the components performing the steps of:

first receiving, by an external network load balancing interface of the load balancing firewall, a request from an external client;

first determining, based upon a load-balancing algorithm, a selected load balancing/firewall node that processes the request from the external client;

establishing, by the selected load balancing/firewall node, a connection state corresponding to the request from the external client;

passing, by the selected load balancing/firewall node, the request from the external client to a selected one of the multiple published servers;

second receiving, by an internal network load balancing interface of the load balancing firewall, a message from the selected one of the multiple published servers;

second determining, in response to the second receiving step, whether the address of the selected one of the multiple published servers is present in the list of published servers; and

applying, by the internal network load balancing interface of the load balancing firewall, a complementary load-balancing algorithm to the message received during the second receiving step, in response to identifying the selected one of the multiple published servers within the list of published server during the second determining step, the complementary load-balancing algorithm determining the selected load balancing/firewall node established during the first determining step; and

processing, by the selected load balancing/firewall node, the message from the selected one of the multiple published servers.

19. The computer-readable medium for establishing bi-directional affinity for a load balancing firewall in claim 18 wherein the applying step further comprises computer-executable instructions facilitating performing the steps of:

applying, by the internal network load balancing interface of the load balancing firewall, a default load-balancing algorithm to the message received during the second receiving step, in response to not identifying the selected one of the multiple published servers within the list of published server during the second determining step, the default load-balancing algorithm differing from the complementary load-balancing algorithm.

20. The computer-readable medium for establishing bi-directional affinity for a load balancing firewall in claim 19 wherein the default algorithm is a modulo algorithm applied to a hash of the message received from the selected one of the multiple published servers.

21. The computer-readable medium for establishing bi-directional affinity for a load balancing firewall in claim 18 comprising further computer-executable instructions facilitating performing the steps of:

passing, by the selected load balancing/firewall node, the message from the selected one of the multiple published servers to the external client; and

receiving, by the external client, the message from the selected load balancing/firewall node.

22. The computer-readable medium for establishing bi-directional affinity for a load balancing firewall in claim 18 wherein the list of published servers comprises a list of IP addresses uniquely identifying the published servers.

23. A method for establishing bi-directional affinity for a load balancing firewall comprising multiple load balancing/firewall nodes interposed between an internal network comprising multiple published servers and an external network comprising requesting clients, the method comprising:

first receiving, by an external network load balancing interface of the load balancing firewall, a request from an external client;

first determining, based upon a load-balancing algorithm, a selected load balancing/firewall node that processes the request from the external client;

evaluating, by the selected load balancing/firewall node, the request from the external client to determine whether to establish bi-directional affinity;

establishing, by the selected load balancing/firewall node, a connection state corresponding to the request from the external client;

passing, by the selected load balancing/firewall node, the request from the external client to a selected one of the multiple published servers;

second receiving, by an internal network load balancing interface of the load balancing firewall, a message from the selected one of the multiple published servers; and

applying, by the internal network load balancing interface of the load balancing firewall, a complementary load-balancing algorithm to the message received during the second receiving step, in response to determining establishment of bi-directional affinity during the evaluating step, the complementary load-balancing algorithm determining the selected load balancing/firewall node established during the first determining step; and

processing, by the selected load balancing/firewall node, the message from the selected one of the multiple published servers.

24. The method for establishing bi-directional affinity for a load balancing firewall in claim 23 wherein the applying step further comprises the steps of:

applying, by the internal network load balancing interface of the load balancing firewall, a default load-balancing algorithm to the message received during the second receiving step, in response to not determining establishment of bi-directional affinity during the evaluating step, the default load-balancing algorithm differing from the complementary load-balancing algorithm.