SYSTEMS AND METHODS OF PREFETCHING OBJECTS FOR CACHING USING QOS

• US 20090287842A1
• Filed: 07/21/2009
• Published: 11/19/2009
• Est. Priority Date: 03/12/2007
• Status: Active Grant

• Current Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Original Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Inventors: Plamondon, Robert
• Granted Patent: US 8,275,829 B2
• Time in Patent Office: Days
• US Class Current: 709/233
• CPC Class Codes: H04L 12/4641 Virtual LANs, VLANs, e.g. virtual private networks [VPN] LAN interconnection over a bridge based backbone H04L12/462; encapsulation techniques H04L12/4633; routing of packets H04L45/00; packet switches H04L49/00; virtual private networks for security H04L63/0272
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/70 Admission control; Resource allocation
• CPC Class Codes: H04L 47/822 Collecting or measuring resource availability data
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]
• CPC Class Codes: H04L 61/4552 Lookup mechanisms between a plurality of directories; Synchronisation of directories, e.g. metadirectories
• CPC Class Codes: H04L 61/58 Caching of addresses or names
• CPC Class Codes: H04L 67/02 based on web technology, e.g. hypertext transfer protocol [HTTP]

Abstract

The present solution provides a variety of techniques for accelerating and optimizing network traffic, such as HTTP based network traffic. The solution described herein provides techniques in the areas of proxy caching, protocol acceleration, domain name resolution acceleration as well as compression improvements. In some cases, the present solution provides various prefetching and/or prefreshening techniques to improve intermediary or proxy caching, such as HTTP proxy caching. In other cases, the present solution provides techniques for accelerating a protocol by improving the efficiency of obtaining and servicing data from an originating server to server to clients. In another cases, the present solution accelerates domain name resolution more quickly. As every HTTP access starts with a URL that includes a hostname that must be resolved via domain name resolution into an IP address, the present solution helps accelerate HTTP access. In some cases, the present solution improves compression techniques by prefetching non-cacheable and cacheable content to use for compressing network traffic, such as HTTP. The acceleration and optimization techniques described herein may be deployed on the client as a client agent or as part of a browser, as well as on any type and form of intermediary device, such as an appliance, proxying device or any type of interception caching and/or proxying device.

Claims

1. A method for prefetching an object responsive to utilization of a connection, the method comprising:

(a) storing in a cache, by an appliance, an object from a server communicated to a client;

(b) determining, by the appliance, that utilization of a connection between the appliance and the server is below a predetermined threshold;

(c) prefetching, by the appliance, the object from the server in response to the determination and storing the prefetched object in the cache.

2. The method of claim 1, wherein step (c) further comprises maintaining the utilization of the connection below the predetermined threshold while prefetching the object.

3. The method of claim 1, wherein step (c) further comprises prefetching the object from the server according to a transmission rate to maintain utilization of bandwidth by the connection within the predetermined threshold.

4. The method of claim 1, wherein step (b) further comprises determining utilization of the connection by determining that an availability of bandwidth of the connection is below the predetermined threshold.

5. The method of claim 1, wherein step (b) further comprises determining that a response time of a response from the server to a request from the appliance is below the predetermined threshold.

6. The method of claim 1, wherein step (b) further comprises determining that a number of prefetching requests in a queue waiting to be transmitted to the server is below the predetermined threshold.

7. The method of claim 1, wherein step (b) further comprises determining that a queue of prefetching packets transitioned from empty to non-empty.

8. The method of claim 1, wherein step (b) further comprises determining that a number of active connections of the appliance is below the predetermined threshold.

9. The method of claim 1, wherein step (b) further comprises determining that a number of active users communicating with the appliance is below the predetermined threshold.

10. The method of claim 1, wherein step (b) further comprises determining that a number of outstanding requests to the server awaiting responses from the server is below the predetermined threshold.

11. The method of claim 1, wherein step (c) further comprises generating, by the appliance, a request for the object, the request identified as a speculative request.

12. A system for prefetching an object responsive to utilization of a connection, the system comprising:

a cache of an appliance storing an object from a server communicated to a client;

a detector determining that utilization of a connection between the appliance and the server is below a predetermined threshold; and

a prefetcher prefetching the object from the server in response to the determination, the prefetched object is stored in the cache.

13. The system of claim 12, wherein the appliance maintains the utilization of the connection below the predetermined threshold while prefetching the object.

14. The system of claim 12, wherein the prefetcher prefetches the object from the server according to a transmission rate to maintain utilization of bandwidth of the connection within the predetermined threshold

15. The system of claim 12, wherein the detector determines utilization of the connection by determining that an availability of bandwidth of the connection is below the predetermined threshold.

16. The system of claim 12, wherein the detector determines utilization of the connection by determining that a response time of a response from the server to a request from the appliance is below the predetermined threshold.

17. The system of claim 12, wherein the detector determines utilization of the connection by determining that a number of prefetching requests in a queue waiting to be transmitted to the server is below the predetermined threshold.

18. The system of claim 12, wherein the detector determines utilization of the connection by determining that a queue of prefetching packets transitioned from empty to non-empty.

19. The system of claim 12, wherein the detector determines utilization of the connection by determining that a number of active connections of the appliance is below the predetermined threshold.

20. The system of claim 12, wherein the detector determines utilization of the connection by determining that a number of number of active users communicating with the appliance is below the predetermined threshold.

21. The system of claim 12, wherein the detector determines utilization of the connection by determining that a number of outstanding requests to the server awaiting responses from the server is below the predetermined threshold.

22. The system of claim 14, wherein the prefetcher generates a request to an object server for the object, the request identified as a speculative request.