Method and apparatus for providing a guaranteed minimum level of performance for content delivery over a network

• US 6,144,996 A
• Filed: 08/12/1998
• Issued: 11/07/2000
• Est. Priority Date: 05/13/1998
• Status: Expired due to Term

• Current Assignee: Palo Alto Networks Incorporated
• Original Assignee: Compaq Computer Corporation (HP Inc.)
• Inventors: Stewart, Christopher H., Pronev, Svilen B., Starnes, Darrell J., Gabler, Jeffrey R., Giap, Steven C., Kothari, Rupali M., Elwahab, Amgad M.
• Primary Examiner(s): Meky, Moustafa M.
• Application Number:
  US09/133,482
• Time in Patent Office: 818 Days
• Field of Search: 709/201, 709/203, 709/212, 709/213, 709/214, 709/216, 709/217, 709/218, 709/219
• US Class Current: 709/217
• CPC Class Codes: G06F 16/957 Browsing optimisation, e.g. caching or content distillation
• CPC Class Codes: G06T 9/00 Image coding bandwidth or redundancy reduction for static pictures H04N1/41; coding or decoding of static colour picture signals H04N1/64; methods or arrangements for coding, decoding, compressing or decompressing digital video signals H04N19/00
• CPC Class Codes: G06V 30/1423 the instrument generating sequences of position coordinates corresponding to handwriting preprocessing or recognising digital ink G06V30/32
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching
• CPC Class Codes: H04L 67/62 Establishing a time schedule for servicing the requests
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A proxy system that offers connection services and acceleration services is disclosed. The acceleration services provide for accelerated delivery of content to requestors (e.g., clients) while guaranteeing a minimum level of service (for content delivery) to the requestors. The acceleration services are facilitated by improved techniques for rapid and efficient delivery of objects from a network (e.g., the Internet) to users. The improved techniques can be utilized in a variety of apparatuses, including a proxy having an acceleration apparatus (e.g., an acceleration server). The acceleration apparatus manages and monitors its utilization of processing resources so that performance of the proxy system can during worst case conditions guarantee a minimum level of service (for content delivery) to the requestors. The proxy system is also well suited for being scaled to provide additional processing resources.

Claims

1. A method for delivering an object to a requestor at a local computer, said method comprising the operations of:

(a) receiving, at an intermediate computer, a request for an object that is primarily stored on a remote computer, the local computer being capable of coupling to the intermediate computer via a first network, and the intermediate computer being capable of coupling to the remote computer via a second network;

(b) determining whether the requested object is available from an object store associated with the intermediate computer, the object store providing temporary secondary storage for objects;

(c) when said determining (b) determines that the requested object is available from the object store,

(c1) retrieving the requested object from the object store, and

(c2) supplying the retrieved object obtained from the object store to the requestor; and

(d) when said determining (b) determines that the requested object is being obtained but is not presently available from the object store,

(d1) awaiting for a determined amount of time for the requested object to become available from the object store,

(d2) subsequently retrieving the requested object from the remote computer when the requested object is still not available after said awaiting for the determined amount of time, and

(d3) thereafter supplying the retrieved object obtained from the remote computer to the requestor.

2. A method as recited in claim 1, wherein the requested object is an image file, and the object store is an image store.

3. A method as recited in claim 2, wherein the image store is stored on the intermediate computer.

4. A method as recited in claim 2,

wherein the requested image file stored in the image store includes at least an accelerated version of the requested image file,

wherein said determining (b) determines whether the accelerated version of the requested image file is available from the image store,

wherein said retrieving (c1) and said supplying (c2) are with respect to the accelerated version of the requested image file, and

wherein said awaiting (d1) is with respect to the accelerated version of the requested image file.

5. A method as recited in claim 4, wherein retrieving (d2) and said supplying (d3) are with respect to an original, non-accelerated version of the requested image file.

6. A method as recited in claim 5, wherein the determined amount of time ensures a worse case responsiveness no worse than would otherwise occur had said method never attempted to produce the accelerated version of the requested image file.

7. A method for delivering content from a remote machine to a local machine, where the local machine couples to a proxy machine, and the proxy machine couples to the remote machine through a network of computers, said method comprising the operations of:

(a) intercepting, at the proxy machine, a web page request in route from the local machine to the remote machine through the network;

(b) allowing the web page request to be sent from the proxy machine to the remote machine;

(c) delivering the requested web page to the proxy machine, the requested web page includes at least one image file request embedded in the requested web page;

(d) forwarding the requested web page from the proxy machine to the local machine;

(e) identifying, at the proxy machine, the at least one image file request in the requested web page;

(f) pre-fetching the identified at least one image file request, with the content for each of the image file requests being obtained from the remote machine associated with the image file request;

(g) attempting to produce an accelerated version for the identified at least one image file request at the proxy machine;

(h) issuing, from the local machine, the at least one image file request embedded in the requested web page subsequent to receiving the request web page at the local machine;

(i) intercepting, at the proxy machine, the at least one image file request in route from the local machine to the remote machine through the network;

(j) preventing the at least one image file request from being sent from the proxy machine to the remote machine for at least a determined period of time while said attempting (g) to produce the accelerated version of the identified at least one image file request is ongoing;

(k) delivering the accelerated version of a requested image file for the identified at least one image file request to the local machine from the proxy machine when said attempting (g) completes within the determined period of time; and

(l) alternatively, delivering an original version of the requested image file for the identified at least one image file request to the local machine from the proxy machine when said attempting (g) does not completes within the determined period of time, the original version of the requested image file being obtained by said pre-fetching (f) from the remote machine or by releasing said preventing (g) so that the at least one image file request is sent from the proxy machine to the remote machine.

8. A method as recited in claim 7, wherein the local machine couples to the proxy machine via a first connection, and the proxy machine couples to the network of computers via a second connection, the second connection supporting substantially greater data transmission rates than the first connection, and

wherein said pre-fetching (f) of the identified at least one image file request from the remote machine associated with the image file request is performed using the second connection of the proxy machine to the network of computers.

9. A method as recited in claim 8, wherein the network of computers is the Internet.

10. A method as recited in claim 7, wherein said identifying (e) and said pre-fetching (f) are performed substantially simultaneously with said forwarding (d).

11. A method as recited in claim 7, wherein during said attempting (g) to produce an accelerated version for the identified at least one image file requests, at least a part one of said delivering (c) and said issuing (h) is concurrently performed.

12. A method as recited in claim 7, wherein said proxy machine includes a proxy server and an acceleration server, and

wherein said pre-fetching (f) and attempting (g) is performed by the acceleration server.

13. A proxy system for distributing data objects, comprising:

a proxy server, said proxy server operates to receive an object request having a requested object from a network browser and to manage the forwarding of the requested object to the network browser, said proxy server being connected to a network; and

an acceleration unit coupled to said proxy server, said acceleration unit being connected to the network through a second connection, said acceleration unit operates to identify the requested object, pre-fetch the requested object having an original size from a content provider coupled to the network, reduce the size of the retrieved object to a reduced size, and provide the requested object with the reduced size to said proxy server,

wherein when the requested object with the reduced size is determined not to be available from said acceleration unit for more than a determined period of time, said proxy server obtains the requested object of the original size from said acceleration unit or from the content provider directly and provides the requested object having the original size to the network browser.

14. A system as recited in claim 13, wherein said acceleration unit comprises:

an accelerator, said accelerator operates when acceleration has been determined to be advisable to receive the requested object having the original size and then to reduce the size of the requested object with the original size so as to produce the requested object with the reduced size;

an acceleration monitor coupled to said accelerator, said acceleration monitor determines whether the requested object with the reduced size has been produced within the determined period of time; and

an object store operatively coupled to said accelerator, said object store operates to store at least the requested object with the reduced size.

15. A system as recited in claim 14, wherein when said acceleration monitor determines that the requested object with the reduced size has not yet been produced within the determined amount of time, then said proxy server forwards the requested object with the original size to the network browser.

16. A system as recited in claim 14, wherein said object store stores objects with the reduced size and objects with the original size, and

wherein when said acceleration monitor determines that the requested object with the reduced size has not yet been produced within the determined amount of time, then said proxy server forwards the requested object with the original size from said object store to the network browser.

17. A system as recited in claim 14, wherein the requested object is an image file.

18. A system as recited in claim 13, wherein said acceleration unit comprises:

an observer, said observer operates to review the requested object to determine whether the requested object is likely capable of being accelerated by said acceleration unit;

an object manager operatively coupled to said observer, said object manager operates to manage the retrieval of the requested object having the original size from the content provider via the second connection to the network, and to examine the requested object to determine whether acceleration would be advisable;

an accelerator operatively coupled to said object manager, said accelerator operates when acceleration has been determined to be advisable to receive the requested object having the original size from said object manager and then to reduce the size of the requested object with the original size so as to produce the requested object with the reduced size;

an acceleration monitor coupled to said image manager and said accelerator, said acceleration monitor determines whether the requested object with the reduced size has been produced within a predetermined amount of time; and

an object store operatively coupled to said accelerator and said object manager, said object store operates to store at least the requested object with the reduced size, and

wherein when said acceleration monitor determines that the requested object with the reduced size has not yet been produced within the determined amount of time, then said proxy server forwards the requested object with the original size to the network browser.

19. A computer readable medium containing program instructions for delivering an object to a requestor at a local computer, said computer readable medium comprising:

first computer readable code for receiving, at an intermediate computer, a request for an object that is primarily stored on a remote computer, the local computer being capable of coupling to the intermediate computer via a first network, and the intermediate computer being capable of coupling to the remote computer via a second network;

second computer readable code for determining whether the requested object is available from an object store associated with the intermediate computer, the object store providing secondary temporarily storage for objects;

third computer readable code for retrieving the requested object from the object store, and supplying the retrieved object obtained from the object store to the requestor, when said second computer readable code determines that the requested object is available from the object store; and

fourth computer readable code for awaiting for a determined amount of time for the requested object to become available from the object store, subsequently retrieving the requested object from the remote computer when the requested object is still not available after said awaiting for the determined amount of time, and thereafter supplying the retrieved object obtained from the remote computer to the requestor, when said second computer readable code determines that the requested object is being obtained but is not presently available from the object store.

20. A computer readable medium 19,

wherein the requested object is an image file, and the object store is an image store,

wherein the requested image file stored in the image store includes at least an accelerated version of the requested image file, and

wherein said second computer readable code determines whether the accelerated version of the requested image file is available from the image store.