Shared buffer for connectionless transfer protocols

• US 8,521,902 B2
• Filed: 12/02/2010
• Issued: 08/27/2013
• Est. Priority Date: 12/02/2010
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Russo, Richard T., Tyler, Aaron Matthew, Reddy, Chandan Rama, Ghosh, Manoj Krishna, Abdelhalim, Alaa H., Seielstad, Roger D., Gurevich, Peter A.
• Primary Examiner(s): Zhang, Shirley
• Assistant Examiner(s): Zouaki, Zakaria
• Application Number:
  US12/959,245
• Publication Number:
  US 20120144060A1
• Time in Patent Office: 999 Days
• Field of Search: 709/234
• US Class Current: 709/234
• CPC Class Codes: H04L 67/06 specially adapted for file transfer, e.g. file transfer protocol [FTP]

Abstract

Described herein are various principles for operating a connectionless content unit transfer protocol to transmit content of a content unit to multiple clients using a shared buffer. A server may transfer content of one or more content units to each of multiple clients upon request from the client using individual buffers. For each content unit being transferred, the server may maintain a count of the aggregate size of buffers for transferring content of that content unit. If the server determines that the aggregate size of the buffers transmitting a particular content unit is larger than the content unit itself, the server may establish a shared buffer for transferring that content unit to clients. A server using a shared buffer in this manner may transfer content of the content unit to clients using the shared buffer until all requesting clients have received the content unit.

Claims

1. A method for distributing a content unit from a server computing device to a plurality of clients, the method comprising:

receiving, by the server computing device, a plurality of requests from the plurality of clients to transfer the content unit using Trivial File Transfer Protocol (TFTP);

beginning transmission, by the server computing device, of the content unit to each client of the plurality of clients from separate buffers of a plurality of buffers using the TFTP, wherein each separate buffer is associated with a particular client;

determining that an aggregate size of the plurality of separate buffers is greater than a threshold that is based on a size of the content unit;

in response to determining that the aggregate size of the plurality of separate buffers is greater than a threshold, establishing a shared buffer with at least a portion of the content unit that was contained in at least one of the separate buffers; and

continuing transmission, by the server computing device, of the content unit to each client of the plurality of clients from the shared buffer using the TFTP.

2. The method of claim 1, wherein at least one of the plurality of clients is an unauthenticated client.

3. The method of claim 2, wherein the TFTP is employed without congestion control.

4. The method of claim 1, wherein beginning transmission of the content unit comprises:

removing data transmitted to a first client from a first buffer of the plurality of buffers; and

inserting data that has yet to be transmitted to the first client to the first buffer.

5. The method of claim 4, wherein establishing the shared buffer comprises:

adding additional data that has yet to be transmitted to the first client to the shared buffer; and

wherein continuing transmission of the content unit comprises;

transmitting the additional data to the first client from the shared buffer; and

transmitting the additional data to a second client from the shared buffer.

6. The method of claim 1, further comprising, following determining that the aggregate size of the plurality of separate buffers is greater than the threshold:

receiving a new request from a new client, different from the plurality of clients; and

transferring content of the content unit to the new client from the shared buffer.

7. The method of claim 1, further comprising, following determining that the aggregate size of the plurality of separate buffers is greater than the threshold:

determining that the content unit has been transferred to each client that requested the content unit; and

deleting data stored in the shared buffer if the server computing device does not receive another request for the content unit within a waiting period.

8. The method of claim 7, further comprising:

retaining the data stored in the shared buffer if the server computing device receives another request for the content unit within a waiting period.

9. The method of claim 7, further comprising, following determining that the aggregate size of the plurality of separate buffers is greater than the threshold:

determining that the content unit has been modified; and

deleting the shared buffer without delaying for the waiting period after in-progress transmissions of the content are finished.

10. At least one computer-readable memory storing computer-executable instructions for causing a computer to perform operations that include:

receiving, at the computer, a plurality of requests from a plurality of clients for the computer to provide a file via Trivial File Transfer Protocol (TFTP);

beginning TFTP transmission of the file to each client of the plurality of clients from separate buffers of a plurality of separate buffers, wherein each separate buffer is associated with a particular client;

determining that an aggregate size of the plurality of separate buffers has reached a threshold relative to a size of the file;

in response to determining that the aggregate size of the plurality of separate buffers has reached the threshold, transferring at least a portion of the file into a shared buffer; and

continuing TFTP transmission of the file to each client of the plurality of clients from the shared buffer.

11. The at least one computer-readable memory of claim 10, wherein beginning transmission of the file comprises:

removing a first block of data that has been transmitted to a first client from a first buffer; and

inserting into the first buffer a second block of data that has not yet been transmitted to the first client.

12. The at least one computer-readable memory of claim 11, wherein transferring at least a portion of the file into a shared buffer comprises:

adding a third block of data to be transferred to the first client to the shared buffer; and

wherein continuing transmission of the content unit comprises;

transmitting the third block of data to the first client from the shared buffer; and

transmitting the third block of data to a second client from the shared buffer.

13. The at least one computer-readable memory of claim 10, wherein the operations further comprise:

determining that the file has been transferred to each client that requested the file; and

deleting at least the portion of the file from the shared buffer if another request for the file is not received by the computer during a waiting period.

14. The at least one computer-readable memory of claim 13, wherein the operations further comprise:

determining that the content unit has been modified; and

deleting the shared buffer without delaying the waiting period after completion of pending transmissions.

15. An server apparatus for distributing files to a plurality of clients, comprising:

a memory and at least one processor that are respectively configured to store and execute instructions that;

receive a plurality of requests from clients of the plurality of clients for the server apparatus to transfer a file using Trivial File Transfer Protocol (TFTP);

begin to TFTP transfer the file to each client of the plurality of clients from separate buffers of a plurality of separate buffers, each buffer being associated with a particular client of the plurality of clients;

determine that a total memory used by the plurality of separate buffers has risen to a threshold; and

in response to the determination that the total memory used by the plurality of separate buffers has risen to a threshold;

establish a shared buffer; and

continue to TFTP transfer the file to each client of the plurality of clients from the shared buffer.

16. The server apparatus of claim 15, wherein the memory and the at least one processor are further configured to store and execute instructions that:

receive another request from another client; and

transfer the file to the other client from the shared buffer.

17. The server apparatus of claim 15, wherein the memory and the at least one processor are further configured to store and execute instructions that:

determine that the file has been transferred to all clients that requested the file; and

delete the shared buffer after a waiting period during which the server apparatus does not receive another request for the file.

18. The server apparatus of claim 15, wherein the memory and the at least one processor are further configured to store and execute instructions that:

determine that the file has been modified; and

in response to the determination that the file has been modified, delete data in the shared buffer.