SMB request prefetching

• US 8,176,141 B1
• Filed: 07/07/2010
• Issued: 05/08/2012
• Est. Priority Date: 07/07/2009
• Status: Active Grant

• Current Assignee: ViaSat Incorporated
• Original Assignee: ViaSat Incorporated
• Inventors: Hepburn, Matthew Ian, Lepeska, Peter, Lambert, Leigh
• Primary Examiner(s): Patel, Haresh N
• Application Number:
  US12/831,609
• Time in Patent Office: 671 Days
• Field of Search: 709208-219, 370/230, 370/401, 370/412, 726/5
• US Class Current: 709/212
• CPC Class Codes: H04L 67/06 specially adapted for file transfer, e.g. file transfer protocol [FTP]
• CPC Class Codes: H04L 67/564 Enhancement of application control based on intercepted application data
• CPC Class Codes: H04L 67/5681 Pre-fetching or pre-delivering data based on network characteristics
• CPC Class Codes: H04L 69/04 Protocols for data compression, e.g. ROHC
• CPC Class Codes: H04L 69/28 Timers or timing mechanisms used in protocols

Abstract

Systems and methods are described for accelerating a user experience involving transactions with a remote file server by identifying and prefetching simple message block (SMB) requests. Embodiments exploit applications'"'"' usage of certain SMB request offset value patterns to reliably prefetch SMB requests. Requests from a user to a remote file server are intercepted by a proxy server disposed in the communications network relatively local to the file server. When a known SMB request offset value is detected and other conditions are met, a set of other SMB request offset values is prefetched by the proxy server according to a predetermined pattern. These prefetched requests may be sent, along with the original request, in a single transaction over the communications link from the proxy server to the requesting user (e.g., via a proxy client associated with the requesting user).

Claims

1. A method for implementing simple message block (SMB) request prefetching, the method comprising:

monitoring, at an optimizer node of a communications system, network traffic to identify an SMB request, the network traffic comprising communications from a user system on a client side of the communications system to an addressable content location on a server side of the communications system, the optimizer node being disposed in the communications system between the user system and the content location; and

when a first SMB request is identified;

analyzing the first SMB request to determine an associated request memory offset indicating a memory offset within a file affected by the first SMB request;

determining whether the request memory offset matches one of a set of known memory offsets maintained by the optimizer node, each of the set of known memory offsets being associated with at least one additional memory offset previously determined as likely to be associated with a second SMB request requested by the user system within a first time threshold subsequent to the first SMB request;

determine whether the first SMB request is an SMB locking request or an SMB unlocking request; and

when the request memory offset matches one of the set of known memory offsets maintained by the optimizer node, prefetching an SMB locking request and an SMB unlocking request, both associated with the at least one additional memory offset;

wherein the prefetching step occurs only when the first SMB request is an SMB locking request.

2. The method of claim 1, wherein monitoring the network traffic to identify an SMB request comprises monitoring the network traffic only to identify either an SMB locking request or an SMB unlocking request.

3. The method of claim 1, further comprising:

identifying a third SMB request as an SMB request prefetched in association with the request memory offset at a prefetch time prior to a request time associated with identifying the first SMB request; and

determining whether a difference between the request time and the prefetch time exceeds a second time threshold,

wherein the prefetching step occurs only when the difference between the request time and the prefetch time exceeds the second time threshold.

4. The method of claim 3, further comprising:

maintaining a list of file identifiers associated with previously prefetched SMB requests; and

analyzing the first SMB request to determine an associated request file identifier indicating the file affected by the first SMB request,

wherein identifying the third SMB request comprises identifying the third SMB request as an SMB request prefetched in association with the request memory offset and further in association with the request file identifier at the prefetch time prior to the request time associated with identifying the first SMB request.

5. The method of claim 3, further comprising:

determining whether the third SMB request is stale,

wherein the prefetching step occurs only when the difference between the request time and the prefetch time exceeds the second time threshold and the third SMB request is stale.

6. The method of claim 3, further comprising:

wherein the second time threshold is ten seconds.

7. The method of claim 1, further comprising:

monitoring, at the optimizer node of the communications system, the network traffic to identify a set of subsequent SMB requests originating from the user system within a second time threshold subsequent to the identifying the first SMB request; and

updating the set of known memory offsets by associating the request memory offset of the first SMB request with the at least one additional memory offset corresponding to the set of subsequent SMB requests.

8. The method of claim 1, wherein the optimizer node is implemented as a proxy server on the server side of the communications system.

9. The method of claim 1, wherein the content location is a file server.

10. A system for implementing simple message block (SMB) request prefetching, the system comprising:

at least one hardware element;

a traffic monitoring subsystem disposed at an optimizer node of a communications system between a user system and a content server and configured to monitor network traffic to identify an SMB request, the network traffic comprising communications from a user system on the client side to a content server on the server side;

a traffic analyzer subsystem, communicatively coupled with the optimizer node, and configured, when a first SMB request is identified, to;

analyze the first SMB request to determine an associated request memory offset indicating a memory offset within a file affected by the first SMB request;

determine whether the request memory offset matches one of a set of known memory offsets maintained by the optimizer node, each of the set of known memory offsets being associated with at least one additional memory offset previously determined as likely to be associated with a second SMB request requested by the user system within a first time threshold subsequent to the first SMB request; and

determine whether the first SMB request is an SMB locking request or an SMB unlocking request; and

a prefetching subsystem, communicatively coupled with the traffic analyzer subsystem, and configured to;

prefetch an SMB locking request and an SMB unlocking request, both associated with the at least one additional memory offset, when the request memory offset matches one of the set of known memory offsets maintained by the optimizer node; and

prefetch the SMB locking request and the SMB unlocking request associated with the at least one additional memory offset only when the first SMB request is an SMB locking request.

11. The system of claim 10, wherein the traffic monitoring subsystem is configured to monitor the network traffic to identify only either an SMB locking request or an SMB unlocking request.

12. The system of claim 10, wherein:

the traffic analyzer subsystem is further configured to;

identify a third SMB request as an SMB request prefetched in association with the request memory offset at a prefetch time prior to a request time associated with identifying the first SMB request; and

determine whether a difference between the request time and the prefetch time exceeds a second time threshold; and

the prefetching subsystem is configured to prefetch the SMB locking request and the SMB unlocking request associated with the at least one additional memory offset only when the difference between the request time and the prefetch time exceeds the second time threshold.

13. The system of claim 12, wherein the traffic analyzer subsystem is further configured to:

maintain a list of file identifiers associated with previously prefetched SMB requests;

analyze the first SMB request to determine an associated request file identifier indicating the file affected by the first SMB request; and

identify the third SMB request as an SMB request prefetched in association with the request memory offset and further in association with the request file identifier at the prefetch time prior to the request time associated with identifying the first SMB request.

14. The system of claim 10, wherein the traffic analyzer subsystem is further configured to:

monitor, at the optimizer node of the communications system, the network traffic to identify a set of subsequent SMB requests originating from the user system within a second time threshold subsequent to the identifying the first SMB request; and

update the set of known memory offsets by associating the request memory offset of the first SMB request with the at least one additional memory offset corresponding to the set of subsequent SMB requests.

15. A non-transitory machine-readable medium having stored thereon a series of instructions which, when executed by a processor, cause the processor to implement simple message block (SMB) request prefetching according to steps comprising:

monitoring, at an optimizer node of a communications system, network traffic to identify either an SMB locking request or an SMB unlocking request, the network traffic comprising communications from a user system on a client side of the communications system to an addressable content location on a server side of the communications system, the optimizer node being disposed in the communications system between the user system and the content location; and

when a first SMB request is identified;

analyzing the first SMB request to determine an associated request memory offset indicating a memory offset within a file affected by the first SMB request;

determining whether the request memory offset matches one of a set of known memory offsets maintained by the optimizer node, each of the set of known memory offsets being associated with at least one additional memory offset previously determined as likely to be associated with a second SMB request requested by the user system within a first time threshold subsequent to the first SMB request;

determine whether the first SMB request is an SMB locking request or an SMB unlocking request; and

when the request memory offset matches one of the set of known memory offsets maintained by the optimizer node, prefetching an SMB locking request and an SMB unlocking request, both associated with the at least one additional memory offset;

wherein the prefetching step occurs only when the first SMB request is an SMB locking request.

16. The machine-readable medium of claim 15, wherein the prefetching step occurs only when the first SMB request is identified as an SMB locking request.

17. The machine-readable medium of claim 15, wherein the series of instructions, when executed by a processor, cause the processor to implement simple message block (SMB) request prefetching according to steps further comprising:

identifying a third SMB request as an SMB request prefetched in association with the request memory offset at a prefetch time prior to a request time associated with identifying the first SMB request; and

determining whether a difference between the request time and the prefetch time exceeds a second time threshold,

wherein the prefetching step occurs only when the difference between the request time and the prefetch time exceeds the second time threshold.

18. The machine-readable medium of claim 17, wherein the series of instructions, when executed by a processor, cause the processor to implement simple message block (SMB) request prefetching according to steps further comprising:

maintaining a list of file identifiers associated with previously prefetched SMB requests; and

analyzing the first SMB request to determine an associated request file identifier indicating the file affected by the first SMB request,

wherein identifying the third SMB request comprises identifying the third SMB request as an SMB request prefetched in association with the request memory offset and further in association with the request file identifier at the prefetch time prior to the request time associated with identifying the first SMB request.