OPTIMIZING PROGRAM REQUESTS OVER A WIDE AREA NETWORK

• US 20090319600A1
• Filed: 06/18/2008
• Published: 12/24/2009
• Est. Priority Date: 06/18/2008
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Sedan, Boaz, Yosevshvili, Moshe, Kaminsky, Daniel, Ran, Etai Lev, Ben-Shaul, Israel
• Granted Patent: US 8,935,336 B2
• Time in Patent Office: Days
• US Class Current: 709/203
• CPC Class Codes: G06F 11/0709 in a distributed system consisting of a plurality of standalone computer nodes, e.g. clusters, client-server systems
• CPC Class Codes: G06F 11/0766 Error or fault reporting or storing

Abstract

In various embodiments, data processing apparatus, software, or machine-implemented methods can optimize NFSv3 asynchronous write requests or MSRPC calls that traverse a wide area network, for example, by receiving, from a client, a first request directed to a server across a wide area network; determining whether a related second request has been received previously; when a related second request has been received previously, sending, to the client, a first reply to the second request and forwarding the first request to the server, and otherwise forwarding the first request to the server without sending any reply to the client for the first request. Sending local replies from a WAN optimizer induces the client to send continuous requests, improving throughput, but at least one client request remains unreplied to, and one server error reply is always reported to the client, facilitating correct error processing at the client.

Claims

1. A data processing apparatus, comprising:

a network interface;

a processor coupled to the network interface;

a machine-readable volatile or non-volatile storage medium coupled to the processor and storing one or more sequences of instructions which, when executed by the processor, cause the processor to perform;

receiving, from a client, a first request directed to a server across a wide area network;

determining whether a related second request has been received previously;

when a related second request has been received previously, sending, to the client, a first reply to the second request and forwarding the first request to the server,

and otherwise forwarding the first request to the server without sending any reply to the client for the first request.

2. The apparatus of claim 1, wherein the first request is to write data for a specified file handle on the server and for a specified user, and wherein the second request is to write data for the same file handle and user.

3. The apparatus of claim 2, further comprising sequences of instructions which, when executed by the processor, cause the processor to perform:

receiving, from the server, a second reply to a third request to write data for a second specified file handle and a second specified user;

determining whether the client has been given a second reply to the third request previously;

forwarding the second reply to the client when the client has not been given a second reply to the third request previously, and otherwise discarding the second reply.

4. The apparatus of claim 2, wherein each request and reply conforms to Network File System protocol version 3 (NFSv3) and wherein each request is an NFSv3 request having an UNSTABLE value set.

5. The apparatus of claim 2, further comprising sequences of instructions which, when executed by the processor, cause the processor to perform:

receiving, from the server, a second reply to a third request to write a second specified file handle and a second specified user;

determining whether the client has been given a second reply to the third request previously;

when the client has not been given a second reply to the third request previously, forwarding the second reply to the client including any error code of the server that is in the second reply, and otherwise discarding the second reply.

6. The apparatus of claim 5, further comprising sequences of instructions which, when executed by the processor, cause the processor to perform:

in response to receiving multiple replies from the server for a plurality of client requests that have been forwarded to the server wherein each of the replies comprises a different server error code, sending to the client the most recently received reply with any server error code in that reply.

7. The apparatus of claim 1, wherein the first request is a first fragment of a remote procedure call that conforms to MSRPC, and wherein the second request is a second fragment of the same remote procedure call.

8. The apparatus of claim 7, further comprising receiving from a transport protocol a delivery failure message specifying a failure to deliver one or more of the first fragment and the second fragment, and sending the delivery failure message to the client in response to receiving a last fragment from the client.

9. A computer-readable medium carrying one or more sequences of instructions which when executed by one or more processors, cause the one or more processors to carry out the steps of:

receiving, from a client, a first request directed to a server across a wide area network;

determining whether a related second request has been received previously;

when a related second request has been received previously, sending, to the client, a first reply to the second request and forwarding the first request to the server,

and otherwise forwarding the first request to the server without sending any reply to the client for the first request.

10. The computer-readable medium of claim 9, wherein the first request is to write data for a specified file handle on the server and for a specified user, and wherein the second request is to write data for the same file handle and user.

11. The computer-readable medium of claim 10, further comprising sequences of instructions which, when executed by the processor, cause the processor to perform:

receiving, from the server, a second reply to a third request to write data for a second specified file handle and a second specified user;

determining whether the client has been given a second reply to the third request previously;

forwarding the second reply to the client when the client has not been given a second reply to the third request previously, and otherwise discarding the second reply.

12. The computer-readable medium of claim 10, wherein each request and reply conforms to Network File System protocol version 3 (NFSv3) and wherein each request is an NFSv3 request having an UNSTABLE value set.

13. The computer-readable medium of claim 10, further comprising sequences of instructions which, when executed by the processor, cause the processor to perform:

receiving, from the server, a second reply to a third request to write a second specified file handle and a second specified user;

determining whether the client has been given a second reply to the third request previously;

when the client has not been given a second reply to the third request previously, forwarding the second reply to the client including any error code of the server that is in the second reply, and otherwise discarding the second reply.

14. The computer-readable medium of claim 13, further comprising sequences of instructions which, when executed by the processor, cause the processor to perform:

in response to receiving multiple replies from the server for a plurality of client requests that have been forwarded to the server wherein each of the replies comprises a different server error code, sending to the client the most recently received reply with any server error code in that reply.

15. The computer-readable medium of claim 9, wherein the first request is a first fragment of a remote procedure call that conforms to MSRPC, and wherein the second request is a second fragment of the same remote procedure call.

16. The computer-readable medium of claim 15, wherein each reply includes a fragment header comprising one or more MSRPC identification values that associate the reply with a corresponding request.

17. An apparatus, comprising:

means for receiving, from a client, a first request directed to a server across a wide area network;

means for determining whether a related second request has been received previously;

means operable when a related second request has been received previously for sending, to the client, a first reply to the second request and forwarding the first request to the server, and

means for otherwise forwarding the first request to the server without sending any reply to the client for the first request.

18. The apparatus of claim 17, wherein the first request is to write data for a specified file handle on the server and for a specified user, and wherein the second request is to write data for the same file handle and user.

19. A machine-implemented method comprising:

receiving, from a client, a first request directed to a server across a wide area network;

determining whether a related second request has been received previously;

when a related second request has been received previously, sending, to the client, a first reply to the second request and forwarding the first request to the server,

and otherwise forwarding the first request to the server without sending any reply to the client for the first request.

20. The method of claim 19, wherein the first request is to write data for a specified file handle on the server and for a specified user, and wherein the second request is to write data for the same file handle and user.

21. The method of claim 20, further comprising sequences of instructions which, when executed by the processor, cause the processor to perform:

receiving, from the server, a second reply to a third request to write data for a second specified file handle and a second specified user;

determining whether the client has been given a second reply to the third request previously;

forwarding the second reply to the client when the client has not been given a second reply to the third request previously, and otherwise discarding the second reply.

22. The method of claim 20, wherein each request and reply conforms to Network File System protocol version 3 (NFSv3) and wherein each request is an NFSv3 request having an UNSTABLE value set.

23. The method of claim 20, wherein the first request is a first fragment of a remote procedure call that conforms to MSRPC, and wherein the second request is a second fragment of the same remote procedure call.

24. A machine-readable volatile or non-volatile storage medium storing one or more sequences of instructions which, when executed by one or more processors, cause the processor to perform:

receiving, from a client computer, a first Network File System protocol version 3 (NFSv3) UNSTABLE type or asynchronous request to write a specified file handle for a specified user identifier directed to a server across a wide area network;

determining whether a second request for the same file handle and user identifier has been received previously;

when a second request has been received previously for the same file handle and user identifier, sending, to the client computer, a first reply to the second request and forwarding the first request to the server, and otherwise forwarding the first request to the server without sending any reply to the client for the first request;

receiving, from the server, a second reply to a third request to write a second specified file handle and a second specified user;

determining whether the client has been given a second reply to the third asynchronous write request previously;

when the client has not been given a second reply to the third request previously, forwarding the second reply to the client including any error code of the server that is in the second reply, and otherwise discarding the second reply.

25. A machine-readable volatile or non-volatile storage medium storing one or more sequences of instructions which, when executed by one or more processors, cause the processor to perform:

receiving, from a client computer, a first fragment of an MSRPC remote procedure call directed to a server across a wide area network;

determining whether a second fragment of the same remote procedure call has been received previously;

when a second fragment of the same remote procedure call has been received previously, sending, to the client computer, a first reply to the second fragment of the same remote procedure call and forwarding the first fragment of the same remote procedure call to the server, and otherwise forwarding the first fragment of the same remote procedure call to the server without sending any reply to the client for the first fragment of the same remote procedure call;

receiving, from the server, a second reply to a third fragment of the same remote procedure call;

determining whether the client process has been given a second reply to the fragment of the same remote procedure call previously;

when the client process has not been given a second reply to the third fragment of the same remote procedure call previously, forwarding the second reply to the client process including any error code of the server that is in the second reply, and otherwise discarding the second reply;

receiving from a transport protocol a delivery failure message specifying a failure to deliver one or more of the first fragment and the second fragment, and sending the delivery failure message to the client process in response to receiving a last fragment from the client process.