Method and apparatus for distributing computer files across a network

• US 20040243675A1
• Filed: 06/02/2003
• Published: 12/02/2004
• Est. Priority Date: 06/02/2003
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Taoyama, Minoru, Truong de la Cueva, Arthur
• Granted Patent: US 7,328,256 B2
• Time in Patent Office: Days
• US Class Current: 709/205
• CPC Class Codes: H04L 67/34 involving the movement of software or configuration parameters network booting or remote initial program loading [RIPL] G06F9/4416
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

One embodiment of the present invention provides a system for distributing files across a network. During operation, the system receives a request at a server to download a file to a client. If the server is not currently downloading the file, the system commences a download stream for the file on a multicast port. If the server is currently downloading the file, the system remembers a marked location on the file, wherein the marked location relates to a current packet number of the download stream on the multicast port. The system then continues downloading the file until the end of the file, thereby allowing the client to receive the remainder of the file. Next, the system downloads the file from the beginning of the file to the marked location, thereby allowing the client to receive previously transmitted portions of the file.

Claims

1. A method for distributing files across a network, comprising:

receiving a request at a server to download a file to a client;

if the server is not currently downloading the file, servicing the request by commencing a download stream for the file on a multicast port; and

if the server is currently downloading the file, servicing the request by,

remembering a marked location in the file, wherein the marked location in the file relates to a current packet number of the download stream on the multicast port,

continuing to download the file until an end of the file, thereby allowing the client to receive the remainder of the file, and

downloading the file from the beginning of the file to the marked location, thereby allowing the client to receive previously transmitted portions of the file.

2. The method of claim 1, wherein if the server receives an additional request from a second client to download the file the method further comprises:

updating the marked location in the file to the current packet number in the download stream;

continuing to download the file until the end of the file, thereby allowing the second client to receive the remainder of the file; and

downloading the file from the beginning of the file to the marked location, thereby allowing the second client to receive previously transmitted portions of the file.

3. The method of claim 1, further comprising:

receiving at the server a notice from the client that a specified packet was not received; and

inserting the specified packet into the download stream.

4. The method of claim 3, wherein if notices are received from multiple clients that the specified packet was not received, inserting the specified packet into the download stream only once to satisfy the notices.

5. A method for receiving files across a network, comprising:

sending a request from a client to a directory server for a network address for a file server;

receiving at the client an address for the file server and a multicast address for a file stream;

requesting a download of a file from the file server; and

receiving the file stream at the multicast address.

6. The method of claim 5, further comprising:

remembering a number for a first received packet in the file stream; and

if the first received packet is not a first packet in the file stream,

reserving a space in a local file for previously transmitted portions of the file from the first packet in the file up to the first received packet in the file stream,

receiving and storing data from the file stream into the local file, and

when an end of the file stream is reached, continuing to receive and store previously transmitted portions of the file from the first packet in the file up to the first received packet, into the reserved space in the local file.

7. The method of claim 6, wherein if a missing packet is detected in the file stream, the method further comprises:

sending a retry request to the file server to resend the missing packet;

monitoring the file stream for the missing packet; and

if the missing packet is received, storing the missing packet in the local file,

otherwise, resending the retry request to the file server after a specified period of time has elapsed.

8. A computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method for distributing files across a network, the method comprising:

receiving a request at a server to download a file to a client;

if the server is not currently downloading the file, servicing the request by commencing a download stream for the file on a multicast port; and

if the server is currently downloading the file, servicing the request by;

remembering a marked location in the file, wherein the marked location in the file relates to a current packet number of the download stream on the multicast port,

continuing to download the file until an end of the file, thereby allowing the client to receive the remainder of the file, and

downloading the file from the beginning of the file to the marked location, thereby allowing the client to receive previously transmitted portions of the file.

9. The computer-readable storage medium of claim 8, wherein if the server receives an additional request from a second client to download the file the method further comprises:

updating the marked location in the file to the current packet number in the download stream;

continuing to download the file until the end of the file, thereby allowing the second client to receive the remainder of the file; and

downloading the file from the beginning of the file to the marked location, thereby allowing the second client to receive previously transmitted portions of the file.

10. The computer-readable storage medium of claim 8, the method further comprising:

receiving at the server a notice from the client that a specified packet was not received; and

inserting the specified packet into the download stream.

11. The computer-readable storage medium of claim 10, wherein if notices are received from multiple clients that the specified packet was not received, inserting the specified packet into the download stream only once to satisfy the notices.

12. A computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method for receiving files across a network, the method comprising:

sending a request from a client to a directory server for a network address for a file server;

receiving at the client an address for the file server and a multicast address for a file stream;

requesting a download of a file from the file server; and

receiving the file stream at the multicast address.

13. The computer-readable storage medium of claim 12, the method further comprising:

remembering a number for a first received packet in the file stream; and

if the first received packet is not a first packet in the file stream,

reserving a space in a local file for previously transmitted portions of the file from the first packet in the file up to the first received packet in the file stream,

receiving and storing data from the file stream into the local file, and

when an end of the file stream is reached, continuing to receive and store previously transmitted portions of the file from the first packet in the file up to the first received packet, into the reserved space in the local file.

14. The computer-readable storage medium of claim 13, wherein if a missing packet is detected in the file stream, the method further comprises:

sending a retry request to the file server to resend the missing packet;

monitoring the file stream for the missing packet; and

if the missing packet is received, storing the missing packet in the local file,

otherwise, resending the retry request to the file server after a specified period of time has elapsed.

15. An apparatus for distributing files across a network, comprising:

a receiving mechanism that is configured to receive a request at a server to download a file to a client;

a servicing mechanism that is configured to service the request by commencing a download stream for the file on a multicast port if the server is not currently downloading the file; and

if the server is currently downloading the file, the servicing mechanism is further configured to service the request by;

remembering a marked location in the file, wherein the marked location in the file relates to a current packet number of the download stream on the multicast port,

continuing to download the file until an end of the file, thereby allowing the client to receive the remainder of the file, and

downloading the file from the beginning of the file to the marked location, thereby allowing the client to receive previously transmitted portions of the file.

16. The apparatus of claim 15, further comprising:

an updating mechanism that is configured to update the marked location in the file to the current packet number in the download stream upon receiving an additional request from a second client to download the file;

wherein the servicing mechanism is further configured to continue to download the file until the end of the file, thereby allowing the second client to receive the remainder of the file; and

wherein the servicing mechanism is further configured to download the file from the beginning of the file to the marked location, thereby allowing the second client to receive previously transmitted portions of the file.

17. The apparatus of claim 15,

wherein the receiving mechanism is further configured to receive a notice at the server from the client that a specified packet was not received;

and

further comprising an inserting mechanism that is configured to insert the specified packet into the download stream.

18. The apparatus of claim 17, wherein if notices are received from multiple clients that the specified packet was not received, the inserting mechanism is further configured to insert the specified packet into the download stream only once to satisfy the notices.

19. An apparatus for receiving files across a network, comprising:

a sending mechanism that is configured to send a request from a client to a directory server for a network address for a file server;

a receiving mechanism at the client that is configured to receive an address for the file server and a multicast address for a file stream;

a requesting mechanism that is configured to request a download of a file from the file server; and

wherein the receiving mechanism is further configured to receive the file stream at the multicast address.

20. The apparatus of claim 19, further comprising:

a remembering mechanism that is configured to remember a number for a first received packet in the file stream;

a reserving mechanism that is configured to reserve a space in a local file for previously transmitted portions of the file from the first packet in the file up to the first received packet in the file stream, if the first received packet is not a first packet in the file stream;

a receiving and storing mechanism that is configured to receive and store data from the file stream into the local file; and

wherein the receiving and storing mechanism is further configured to continuing to receive and store previously transmitted portions of the file from the first packet in the file up to the first received packet into the reserved space in the local file when an end of the file stream is reached.

21. The apparatus of claim 20, wherein if a missing packet is detected in the file stream, the apparatus further comprises:

a retry mechanism that is configured to send a retry request to the file server to resend the missing packet;

a monitoring mechanism that is configured to monitor the file stream for the missing packet;

a storing mechanism that is configured to store the missing packet in the local file if the missing packet is received; and

a resending mechanism that is configured to resend the retry request to the file server after a specified period of time has elapsed.