Data delivery system and method for delivering computer data over a broadcast network

• US 6,041,359 A
• Filed: 06/09/1997
• Issued: 03/21/2000
• Est. Priority Date: 06/09/1997
• Status: Expired due to Term

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Birdwell, Kenneth J.
• Primary Examiner(s): Geckil, Mehmet B.
• Application Number:
  US08/871,655
• Time in Patent Office: 1,016 Days
• Field of Search: 395/200.68, 395/200.56, 395/200.61, 395/200.47, 709/238, 709/226, 709/231, 709/217
• US Class Current: 709/238
• CPC Class Codes: H04L 12/1877 Measures taken prior to transmission
• CPC Class Codes: H04L 12/189 in combination with wireless systems selective distribution or broadcast in wireless communication networks H04W4/06
• CPC Class Codes: H04L 47/70 Admission control; Resource allocation
• CPC Class Codes: H04L 47/724 at intermediate nodes, e.g. resource reservation protocol [RSVP]
• CPC Class Codes: H04L 47/745 Reaction in network
• CPC Class Codes: H04L 47/781 Centralised allocation of resources
• CPC Class Codes: H04L 47/806 Broadcast or multicast traffic
• CPC Class Codes: H04L 47/822 Collecting or measuring resource availability data
• CPC Class Codes: H04L 47/826 Involving periods of time
• CPC Class Codes: H04L 67/01 Protocols
• CPC Class Codes: H04L 67/1076 Resource dissemination mechanisms or network resource keeping policies for optimal resource availability in the overlay network
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A data delivery system facilitates broadcast delivery of computer data and other content from multiple content servers to multiple clients. The servers are connected to a broadcast center via a bi-directional data network, such as an ATM network or an Ethernet. The data is served over the data network from the content servers to the broadcast center where it is broadcast over a broadcast network (i.e., satellite, RF, microwave, etc.) to the clients. The clients are equipped to receive broadcast transmissions from the broadcast center. Due to the unidirectional broadcast link, the clients are unable to communicate with the servers to acknowledge receipt or pre-reserve bandwidth over the data network. The broadcast center performs this task on behalf of the clients. To assure delivery of the data from the servers over the data network to the broadcast center for retransmission, the content servers generate requests for reservation of bandwidth on the data network for an upcoming time period and submit the requests over the data network to the broadcast center prior to the time period. The broadcast network schedules reservations of the bandwidth for the upcoming time period and, when the time period arrives, reserves the bandwidth at the time the communication link between the server and the broadcast center is being established.

Claims

1. A data delivery system for delivering data over a unidirectional broadcast network, comprising:

multiple content servers connected to serve data over a bi-directional data network;

a broadcast center connected to receive the data served from the content servers over the bi-directional data network and to broadcast the data over the unidirectional broadcast network to multiple clients;

the content servers generating requests for reservation of bandwidth on the data network for an upcoming time period and submitting the requests over the data network to the broadcast center before the time period; and

the broadcast center reserving the bandwidth for the content servers in response to the requests.

2. A data delivery system as recited in claim 1, wherein the broadcast center evaluates whether the bandwidth requested by the content servers is available for allocation and reserves the bandwidth if it is available for allocation.

3. A data delivery system as recited in claim 1, wherein the broadcast center maintains a list of bandwidth reservations for the content servers.

4. A data delivery system as recited in claim 1, wherein:

a particular content server submits a bandwidth reservation request for a particular quantity of bandwidth during a particular time period; and

the broadcast center compares the bandwidth reservation request to other requests involving the time period and determines an actual quantity of bandwidth that can be allocated during the time period.

5. A data delivery system as recited in claim 4, wherein the broadcast center reserves the actual quantity of bandwidth for the time period for allocation to the particular content server.

6. A data delivery system as recited in claim 5, wherein:

the broadcast center sends the reservation to the particular content over the data network; and

the particular content server determines whether to accept or cancel the reservation.

7. A data delivery system as recited in claim 1, wherein, for a particular time period, the broadcast center sends bandwidth reservation messages over the data network to reserve the bandwidth on the data network to assure delivery of the data from the content servers to the broadcast center.

8. A data delivery system as recited in claim 1, wherein the broadcast center comprises:

a reservation computing unit coupled to the bi-directional data network to handle the bandwidth reservation requests from the content servers;

a signal generator to generate a broadcast signal to carry the data served from the content servers over the broadcast network; and

a transmitter coupled to the signal generator to send the broadcast signal over the broadcast network.

9. A broadcast center for receiving data from multiple content servers over a bi-directional data network and broadcasting that data over a broadcast network to multiple clients, comprising:

a reservation computing unit which receives bandwidth reservation requests from the content servers, each bandwidth reservation request specifying a quantity of bandwidth and a time slot in which a requesting content server desires to serve data over the data network for broadcast by the broadcast center;

the reservation computing unit determining whether the quantity of bandwidth requested can be accommodated, and if so, reserving the bandwidths at corresponding time slots requested by the content servers;

a signal generator to generate a broadcast signal carrying the data served by the content servers; and

a transmitter, coupled to the signal generator, to broadcast the broadcast signal over the broadcast network to the clients.

10. A broadcast center as recited in claim 9, wherein the reservation computing unit comprises a router.

11. A broadcast center as recited in claim 9, wherein the reservation computing unit notifies the content servers of the reserved bandwidths.

12. A broadcast center as recited in claim 9, wherein the reservation computing unit evaluates whether the bandwidths requested by the content servers are available for allocation.

13. A broadcast center as recited in claim 9, wherein the reservation computing unit compares the bandwidth reservation requests for a particular time slot and determines an actual quantity of bandwidth that can be allocated to the content servers.

14. A broadcast center as recited in claim 13, wherein the reservation computing unit reserves the actual quantity of bandwidth for the time slot.

15. A broadcast center as recited in claim 9, wherein the reservation computing unit sends bandwidth reservation messages at reserved time slots to particular ones of the content servers to reserve bandwidth on the bi-directional data network between the particular content servers and the reservation computing unit.

16. A broadcast center as recited in claim 9, wherein the reservation computing unit converts data received in a first format from the content servers into a second format which is passed onto the signal generator.

17. In a network system having multiple content servers serving data to multiple clients over a distribution network with a bi-directional link and a unidirectional broadcast link, the content servers sending the data over the bi-directional link in a first format, a reservation computing unit comprising:

a network port to provide access to the bi-directional link of the distribution network, the network port receiving bandwidth reservation requests from the content servers requesting reservation of bandwidth on the data network;

a scheduler to schedule bandwidth reservations for the content servers in response to the requests;

a second port to provide access to the unidirectional broadcast link of the distribution network; and

a data format converter to convert the data from the first format into a second format for transmission over the unidirectional broadcast link of the distribution network.

18. A reservation computing unit as recited in claim 17, wherein the scheduler generates reservation notices to inform the content servers that the bandwidths are reserved, the network port transmitting the reservation notices to the content servers over the bi-directional link of the distribution network.

19. A reservation computing unit as recited in claim 17, wherein the scheduler evaluates whether the bandwidths requested by the content servers are available for allocation.

20. A reservation computing unit as recited in claim 17, further comprising a bandwidth reservation table to store the bandwidth reservations.

21. A reservation computing unit as recited in claim 20, wherein the scheduler compares individual bandwidth reservation requests to the reservations stored in the bandwidth reservation table for a time slot and determines an actual quantity of bandwidth that can be allocated for the requesting content servers during that time slot.

22. A reservation computing unit as recited in claim 21, wherein the scheduler reserves the actual quantity of bandwidth for the time slot.

23. A reservation computing unit as recited in claim 17, wherein during a particular time slot, the scheduler generates bandwidth reservation messages which are sent by the network port over the bi-directional link of the distribution network to particular content servers to reserve bandwidth on the distribution network between the particular content servers and the reservation computing unit.

24. In a data delivery system in which data is delivered from a server to a client at least partly over a unidirectional broadcast network in which the client is unable to communicate with the server to reserve bandwidth for the data delivery, a client surrogate computing unit interposed between the server and the client and capable of conducting bi-directional communication with the server, the client surrogate computing unit being configured to reserve bandwidth on behalf of the client for the data delivery from the server to the client and to convert the data received from the server into a format for broadcast delivery of the data over the unidirectional broadcast network.

25. In a data delivery system in which data from multiple content servers is sent over a data network to a broadcast center for broadcast over a unidirectional broadcast network to multiple clients, a method comprising the following steps:

generating, at a requesting content server, a bandwidth reservation request for reservation of bandwidth on the data network for an upcoming time period;

sending the bandwidth reservation request over the data network to the broadcast center before the time period;

reserving the bandwidth on the data network for the time period requested by the requesting content server;

sending the data from the requesting content server over the data network to the broadcast center; and

broadcasting the data from the broadcast center over a unidirectional broadcast network to the multiple clients.

26. A method as recited in claim 25, further comprising the step of evaluating, at the broadcast center, whether the bandwidth requested by the requesting content server is available for allocation.

27. A method as recited in claim 25, further comprising the step of storing the bandwidth reservation request at the broadcast center.

28. A method as recited in claim 25, further comprising the following steps:

comparing the bandwidth reservation request with other requests for the time period; and

determining an actual quantity of bandwidth that can be allocated to the requesting content server during the time period.

29. A method as recited in claim 28, further comprising the following steps:

reserving the actual bandwidth for the requesting content server;

sending a reservation for the actual bandwidth from the broadcast center to the requesting content server over the data network; and

determining, at the requesting content server, whether to accept or cancel the reservation.

30. A method as recited in claim 25, further comprising the step of initiating from the broadcast center, at commencement of the time period, a bandwidth reservation message for reserving the bandwidth on the data network to assure delivery of the data from the content server to the broadcast center.

31. Computer-readable media having computer-executable instructions executable at the broadcast center and the content servers for performing the steps of the method as recited in claim 25.

32. In a data delivery system in which data from multiple content servers is sent over a data network to a broadcast center for broadcast over a broadcast network to multiple clients, a method for operating the broadcast center comprising the following steps:

reserving, in advance, bandwidth on the data network to be used by a content server to send data over the data network during an upcoming time period;

before commencement of the time period, generating bandwidth reservation messages and sending the bandwidth reservation messages over the data network to the content servers to timely reserve network resources to assure transmission of the data from the content servers to the broadcast center during the time period;

receiving the data from the content server over the data network during the time period; and

broadcasting the data from the broadcast center over a unidirectional broadcast network to the multiple clients.

33. A method as recited in claim 32, further comprising the following steps:

receiving a bandwidth reservation request from the content server requesting reservation of a quantity of bandwidth at a particular time period; and

evaluating whether the quantity of bandwidth requested by the content server is available for allocation.

34. A method as recited in claim 32, further comprising the following steps:

receiving a bandwidth reservation request from the content server requesting reservation of a quantity of bandwidth at a particular time period; and

comparing the bandwidth reservation request with other bandwidth reservation requests for the particular time period to determine an actual quantity of bandwidth that can be allocated to the requesting content server.

35. A method as recited in claim 32, further comprising the following steps:

receiving multiple bandwidth reservation requests from multiple content servers requesting reservation of bandwidth at different time periods; and

storing the bandwidth reservation requests.

36. A computer programmed to perform the steps recited in the method of claim 32.

37. A computer-readable medium having computer-executable instructions for performing the steps of the method as recited in claim 32.