System for distributing objects to multiple clients

• US 20040003104A1
• Filed: 06/27/2002
• Published: 01/01/2004
• Est. Priority Date: 06/27/2002
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Ivashin, Victor, Miceli, Sean, Boskovic, Ronald
• Granted Patent: US 7,043,559 B2
• Time in Patent Office: Days
• US Class Current: 709/231
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/15 in relation to multipoint traffic arrangements for broadcast or multicast in data networks H04L12/18
• CPC Class Codes: H04L 47/30 in combination with information about buffer occupancy at either end or at transit nodes
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/4053 without floor control
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04N 7/152 Multipoint control units therefor

Abstract

A method for updating a subset of a frame of an image is provided. The frame of the image is subdivided into a plurality of tiles. The method initiates with providing a fixed-size queue having a stationary last packet at a bottom of the fixed size queue. Then, a plurality of packets is stored in a time sorted order above the last packet, the plurality of packets corresponding to a frame of an image. Next, an updated packet is received, the updated packet corresponds to a previously received packet of the plurality of packets. Then, the previously received packet is replaced with the updated packet while maintaining the time sorted order. Replacing the previously received packet includes: identifying the previously received packet adjusting any pointers pointing at the previously received packet to point at a packet below the previously received packet; and moving the previously received packet to a top of the fixed size queue. An apparatus and system for distributing packets through a multi point dispatcher between multiple clients is also provided.

Claims

1. A method for updating a set of images for a presentation through a single-buffered multipoint dispatcher over a network to multiple clients, comprising:

defining a set of screens included in a presentation;

dividing each screen of the set of screens into tiles;

storing packets corresponding to each of the tiles of a first screen in a single buffered multipoint dispatcher according to a time sorted hierarchy, wherein a top packet has a most recent time value and a bottom packet has a least recent time value;

comparing each of the tiles of the first screen with corresponding tiles of a second screen to determine non-matching tiles between the first screen and the second screen;

providing packets corresponding to each of the non-matching tiles to the single buffered multipoint dispatcher; and

replacing packets corresponding to each of the non-matching tiles of the first screen with packets corresponding to each of the non-matching tiles of the second screen while maintaining the time sorted hierarchy, wherein the replacing packets while maintaining the time sorted hierarchy allows for supporting clients with different connection speeds at different frame rates.

2. The method of claim 1, wherein the method operation of storing packets corresponding to each of the tiles of a first screen in a single buffered multipoint dispatcher according to a time sorted hierarchy, includes:

placing each of the packets in a fixed size queue according to a time introduced into the single buffered multipoint dispatcher.

3. The method of claim 1, wherein the method operation of providing packets corresponding to each of the non-matching tiles to the single buffered multipoint dispatcher, includes:

grouping multiple packets together to define a single packet to be supplied to the single buffered multipoint dispatcher.

4. The method of claim 3, wherein the multiple packets are grouped according to a time stamp and an index.

5. The method of claim 1, wherein in response to replacing packets, the method includes:

identifying a pointer pointing at one of the replaced packets; and

moving the pointer to point at a packet below the one of the replaced packets.

6. The method of claim 1, wherein the single buffered multipoint dispatcher includes a bandwidth control channel configured to support a regulating protocol enabling the single buffered multipoint dispatcher to notify a process feeding the packets to modify a delivery speed based upon a client latency.

7. A method for distributing packets through a multi point dispatcher having a fixed-size buffer shared between multiple clients, comprising:

providing a fixed-size queue configured to contain a plurality of packets;

defining a client pointer for one of the multiple clients, the client pointer indicating a most recent packet in the queue received by the one of the multiple clients;

receiving an updated packet corresponding to a previously received packet in the queue; and

replacing the previously received packet in the queue with the updated packet, the replacing including;

determining if the client pointer is pointing to the packet being replaced;

if the client pointer is pointing to the packet being replaced, the method includes adjusting the client pointer pointing to the packet being replaced to point to a packet below the packet being replaced.

8. The method of claim 7, wherein the fixed size queue includes a head and a tail.

9. The method of claim 8, further including:

adding a new client to receive the packets by pointing a pointer associated with the new client at the tail of the fixed size queue.

10. The method of claim 7, wherein the packets in the fixed size queue are time sorted.

11. The method of claim 7, wherein the packets in the fixed size queue are doubly linked.

12. The method of claim 7, wherein the method operation of receiving an updated packet corresponding to a previously received packet in the queue, includes:

locating the previously received packet in the queue;

replacing the previously received packet with the updated packet; and

moving the previously received packet to a top of the queue.

13. The method of claim 10, wherein a client having a slower connection speed is provided a slower frame rate by maintaining the time sort in the fixed size queue.

14. A method for updating a subset of a frame of an image, the frame being subdivided into a plurality of tiles, comprising:

providing a fixed-size queue having a stationary last packet at a bottom of the fixed size queue;

storing a plurality of packets in a time sorted order above the last packet, the plurality of packets corresponding to a frame of an image;

receiving an updated packet corresponding to a previously received packet of the plurality of packets; and

replacing the previously received packet with the updated packet while maintaining the time sorted order, the replacing including,

identifying the previously received packet;

adjusting any pointers pointing at the previously received packet to point at a packet below the previously received packet; and

moving the previously received packet to a top of the fixed size queue.

15. The method of claim 14, wherein the fixed size queue includes a most recently received packet at a top of the queue, the most recently received packet having a pointer pointing to the most recently received packet.

16. The method of claim 14, wherein the plurality of packets are configured as a doubly-linked list.

17. The method of claim 15, further including:

providing bandwidth control for a client.

18. The method of claim 17, wherein the method operation of providing bandwidth control for a client includes:

determining a most recent time stamp by locating the pointer pointing to the most recently received packet;

determining a time stamp corresponding to a packet pointed at by the client pointer;

calculating a difference between the most recent time stamp and the time stamp corresponding to the packet pointed at by the client pointer; and

in response to the difference being above a threshold value, the method includes,

requesting a capture process to capture screens at a greater interval.

19. The method of claim 14, wherein the plurality of packets correspond to a plurality of image tiles of a frame, the plurality of image tiles within the frame capable of varying in size.

20. A computer readable media having program instructions for updating a subset of a frame of an image, the frame being subdivided into a plurality of tiles, comprising:

program instructions for storing a plurality of packets in a time sorted order in a fixed-size queue having a stationary last packet at a bottom of the fixed size queue, the plurality of packets corresponding to a frame of an image;

program instructions for receiving an updated packet corresponding to a previously received packet of the plurality of packets; and

program instructions for replacing the previously received packet with the updated packet while maintaining the time sorted order, the program instructions for replacing including,

program instructions for identifying the previously received packet;

program instructions for adjusting any pointers pointing at the previously received packet to point at a packet below the previously received packet; and

program instructions for moving the previously received packet to a top of the fixed size queue.

21. The computer readable media of claim 20, wherein the fixed size queue includes a most recently received packet at a top of the queue, the most recently received packet having a pointer pointing to the most recently received packet.

22. The computer readable media of claim 20, wherein the plurality of packets are configured as a doubly-linked list.

23. The computer readable media of claim 20, further including:

program instructions for providing bandwidth control for a client.

24. The computer readable media of claim 23, wherein the program instructions for providing bandwidth control for a client includes:

program instructions for determining a most recent time stamp by locating the pointer pointing to the most recently received packet;

program instructions for determining a time stamp corresponding to a packet pointed at by the client pointer;

program instructions for calculating a difference between the most recent time stamp and the time stamp corresponding to the packet pointed at by the client pointer; and

in response to the difference being above a threshold value, the method includes,

program instructions for requesting a capture process to capture screens at a greater interval.

25. An integrated circuit chip configured to dispatch updates to objects in a pre-defined set of objects, comprising:

logic for storing a plurality of packets in a time sorted order in a fixed-size queue having a stationary last packet at a bottom of the fixed size queue, the plurality of packets corresponding to a frame of an image;

logic for receiving an updated packet corresponding to a previously received packet of the plurality of packets; and

logic for replacing the previously received packet with the updated packet while maintaining the time sorted order, the logic for replacing including,

logic for identifying the previously received packet;

logic for adjusting any pointers pointing at the previously received packet to point at a packet below the previously received packet; and

logic for moving the previously received packet to a top of the fixed size queue.

26. The integrated circuit chip of claim 25, wherein the integrated circuit chip is located on a printed circuit board.

27. The integrated circuit chip of claim 25, further including:

logic for providing bandwidth control.

28. A system for distributing objects to multiple clients, comprising:

a plurality of clients, each of the plurality of clients configured to receive image data for display on a computer monitor, the image data being updated periodically;

a server in communication with the client, the server including,

a dispatcher enabled to store a first set of packets defining the image in a fixed-size queue shared by the plurality of clients, the first set of packets being stored according to an introduction into the fixed size queue where a most recently introduced packet is stored at a top of the fixed size queue and a least recently introduced packet is stored at a bottom of the fixed size queue, the dispatcher configured to receive an updated packet, the updated packet replacing a corresponding packet of the first set of packets;

a client pointer associated with each of the plurality of clients, the client pointer pointing to a most recently received packet for the corresponding client, wherein the client pointer is configured to point to a next lower packet in the fixed size queue when the updated packet the most recently received packet for the corresponding client.

29. The system of claim 28, wherein the first set of packets are configured as a doubly linked list.

30. The system of claim 29, wherein the doubly linked list includes a head and a tail.

31. The system of claim 30, wherein a new client is added by creating a new client pointer, the new client pointer initially pointing to the tail of the doubly linked list.

32. The system of claim 28, wherein the server includes a packet serving process, the packet serving process configured to transmit updated packets to the dispatcher.