Dynamic Transaction-Persistent Server Load Balancing

• US 20120278440A1
• Filed: 04/27/2011
• Published: 11/01/2012
• Est. Priority Date: 04/27/2011
• Status: Active Grant

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Aruba Networks Incorporated (Hewlett-Packard Enterprise Company)
• Inventors: Iyer, Pradeep
• Granted Patent: US 10,169,094 B2
• Time in Patent Office: Days
• US Class Current: 709/219
• CPC Class Codes: G06F 9/505 considering the load
• CPC Class Codes: H04L 63/0892 by using authentication-authorization-accounting [AAA] servers or protocols
• 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 67/1029 using data related to the state of servers by a load balancer

Abstract

The present disclosure describes a system for dynamic transaction-persistent server load balancing. The disclosed system receives a client request associated with a new transaction. In response to receiving the client request, the system dynamically infers relative capacities of a plurality of servers coupled to the device in a network. In particular, the system maintains a set of variables corresponding to the servers. Each variable indicates a number of outstanding requests transmitted from the device to a respective server. The system infers relative server capacities and transmission latencies between the device and the servers based on a comparison of current values of the variables. The system identifies and selects a server associated with high capacity or low transmission latency between the device and the server relative to one or more other servers, and transmits an outstanding request corresponding to the client request from the new transaction to the identified server.

Claims

1. A method comprising:

receiving, at a device in a network, a client request associated with a new transaction;

dynamically inferring, by the device, relative capacities of a plurality of servers;

selecting a server from the plurality of servers based on the inferred relative capacities to process requests associated with the new transaction; and

transmitting, from the device to a selected server, a request corresponding to the client request.

2. The method of claim 1, further comprising:

maintaining, at the device, a set of variables corresponding to a plurality of servers that are coupled to the device in a network, wherein a respective variable indicates a number of outstanding requests transmitted from the device to a respective server in the plurality of servers.

3. The method of claim 2, wherein dynamically inferring the relative capacities comprises:

responsive to receiving the client request,

determining, by the device, relative capacities of the servers and transmission latencies between the device and the servers based on a comparison of current values of the variables corresponding to the servers; and

identifying, by the device, a server which is associated with high capacity and low transmission latency between the device and the server relative to one or more other servers.

4. The method of claim 2, wherein maintaining the set of variables comprises:

responsive to receiving, at the device, a response from a server corresponding to a previously transmitted request to the server, updating the value of the variable corresponding to the server based on decreased number of outstanding requests;

responsive to the previously transmitted request to the server being expired, updating the value of the variable corresponding to the server based on decreased number of outstanding requests; and

responsive to transmitting a respective request from the device, updating the value of the variable corresponding to the corresponding server based on increased number of outstanding requests.

5. The method of claim 2, wherein identifying the server comprises identifying the server associated with highest capacity or lowest transmission latency between the device and the servers.

6. The method of claim 1, wherein subsequent requests associated with the new transaction are transmitted to the server corresponding to previously transmitted request associated with the new transaction.

7. The method of claim 1, wherein the outstanding requests correspond to a plurality of transactions.

8. The method of claim 1, wherein the device is one of an access point and a controller which is coupled to one or more access points.

9. The method of claim 6, wherein the servers are authentication servers, and wherein the transactions are authentication transactions.

10. The method of claim 7, wherein the device is a Network Access Server (NAS) client, wherein the authentication servers are Remote Authentication Dial-In User Service (RADIUS) severs, and wherein the authentication transactions are performed using an authentication method in compliance with Electrical and Electronics Engineers (IEEE) 802.1X standard.

11. The method of claim 9, wherein the outstanding requests comprise one or more of access requests and accounting requests to the servers.

12. The method of claim 10, wherein each of the plurality of severs is a proxy RADIUS server to a respective server farm, and wherein requests associated with the same IEEE 802.1X transaction are transmitted to the same server farm through the corresponding proxy RADIUS server.

13. A system comprising:

a processor;

a memory;

a receiving mechanism coupled to the processor and the memory, the receiving mechanism receiving a client request associated with a new transaction;

an inferring mechanism coupled to the processor and the memory, the inferring mechanism inferring relative capacities of a plurality of servers;

a selecting mechanism coupled to the processor and the memory, the selecting mechanism selecting a server from the plurality of servers based on the inferred relative capacities to process requests associated with the new transaction; and

a transmitting mechanism coupled to the processor and the memory, the transmitting mechanism transmitting, to a selected server, a request corresponding to the client request.

14. The system of claim 13, further comprising:

an authentication mechanism, coupled to the processor and the memory, that;

maintains a set of variables corresponding to a plurality of servers that are coupled to the device in a network, wherein a respective variable indicates a number of outstanding requests transmitted from the device to a respective server in the plurality of servers;

wherein, responsive to receiving the client request, the inferring mechanism further;

determines relative capacities of the servers and transmission latencies between the device and the servers based on a comparison of current values of the variables corresponding to the servers; and

identifies a server which is associated with high capacity and low transmission latency between the device and the server relative to one or more other servers.

15. The system of claim 14, wherein the authentication mechanism, while maintaining the set of variables, further:

updates the value of the variable corresponding to the server based on decreased number of outstanding requests responsive to receiving a response from a server corresponding to a previously transmitted request to the server;

updates the value of the variable corresponding to the server based on decreased number of outstanding requests responsive to the previously transmitted request to the server being expired; and

updates the value of the variable corresponding to the corresponding server based on increased number of outstanding requests responsive to transmitting a respective request from the device.

16. The system of claim 13, wherein the selecting mechanism selects the server associated with highest capacity or lowest transmission latency between the device and the servers.

17. The system of claim 13, wherein subsequent requests associated with an initialized transaction are transmitted to the server corresponding to previously transmitted request associated with the initialized transaction.

18. The system of claim 13, wherein the outstanding requests correspond to a plurality of transactions.

19. The system of claim 18, wherein the device is a Network Access Server (NAS) client, wherein the servers are Remote Authentication Dial-In User Service (RADIUS) severs, and wherein the transactions are authentication transactions performed using an authentication method in compliance with Electrical and Electronics Engineers (IEEE) 802.1X standard.

20. A non-transitory computer-readable storage medium storing embedded instructions to perform a method, wherein the method comprises:

receiving a client request associated with a new transaction;

dynamically inferring relative capacities of a plurality of servers;

selecting a server from the plurality of servers based on the inferred relative capacities to process requests associated with the new transaction; and

transmitting, to the selected server, a request corresponding to the client request.