Dynamic assignment of multicast network addresses

• US 6,018,771 A
• Filed: 11/25/1992
• Issued: 01/25/2000
• Est. Priority Date: 11/25/1992
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Digital Equipment Corporation (HP Inc.)
• Inventors: Hayden, Peter C.
• Primary Examiner(s): Follansbee, John A.
• Application Number:
  US07/981,274
• Time in Patent Office: 2,617 Days
• Field of Search: 395/800, 395/200, 340/825.5, 370/85.13, 370/432, 709/231
• US Class Current: 709/231
• CPC Class Codes: H04L 12/18 for broadcast or conference , e.g. multicast
• CPC Class Codes: H04L 2101/604 Address structures or formats
• CPC Class Codes: H04L 61/5038 for local use, e.g. in LAN or USB networks, or in a controller area network [CAN]
• CPC Class Codes: H04L 61/5046 Resolving address allocation conflicts; Testing of addresses testing when self-assigning an address H04L61/5092
• CPC Class Codes: H04L 61/5061 Pools of addresses
• CPC Class Codes: H04L 61/5069 for group communication, multicast communication or broadcast communication

Abstract

Multicast addresses on a computer network are dynamically assigned to a temporary node task. In particular, a server dynamically assigns a multicast address to a data stream in response to a request for the data stream from a client. The server assigns the multicast address in cooperation with other servers from a pool of network-allocated but unassigned multicast addresses. Once the data stream is terminated, the assigned multicast address is deassigned and returned to the pool of unassigned multicast addresses for possible reuse by the nodes.

Claims

1. In a network of computers interconnected by a network structure including a plurality of multicast addresses, and at least one transmitter computer for transmitting at least one data stream over the network structure to a plurality of remote receiver computers, a method of transmitting a data stream to a dynamically assigned multicast address, comprising the steps of:

selecting a multicast address that is not being used by any computer on the network;

assigning the selected multicast address to the data stream; and

transmitting the data stream from the at least one transmitter computer to the assigned multicast address for receipt by the receiver computers.

2. The method according to claim 1 wherein the step of selecting comprises randomly selecting the multicast address from a pool of unassigned multicast addresses.

3. The method according to claim 1 wherein the step of selecting is in response to a request for a data stream transmission.

4. The method according to claim 1 further comprising the step of transmitting an announcement to a dedicated multicast address before the step of transmitting the data stream to notify the computers that the selected multicast address has been assigned.

5. In a network of computers interconnected by a network structure and having at least one server computer for transmitting at least one data stream over the network structure to a plurality of client computers, a method of dynamically assigning a multicast address to one data stream from a server computer, comprising the steps of:

receiving a request for a data stream transmission;

generating a list of unassigned multicast addresses that are not being used by any computer on the network;

selecting a candidate multicast address from the list of unassigned multicast addresses;

announcing, to a dedicated multicast address, the candidate multicast address;

monitoring the dedicated multicast address for conflicts between the selected candidate multicast address and other announced multicast addresses;

resolving conflicts between the selected candidate multicast address and other announced multicast addresses to determine a transmission multicast address; and

transmitting the data stream from the server computer to the transmission multicast address for receipt by the plurality of client computers.

6. The method according to claim 5 wherein the step of selecting a candidate multicast address comprises selecting an address at random from the list of unassigned addresses.

7. The method according to claim 5 wherein the server computers and client computers each have a unique respective network address on the network and the step of resolving conflicts is based on the network addresses of conflicting server computers.

8. The method according to claim 5 wherein the step of announcing is performed at a periodic announcement interval.

9. A method according to claim 8 wherein the step of announcing is performed at least twice during a first announcement interval occurring after a candidate address is selected.

10. A system for transmitting a data stream over a computer network having a plurality of computer nodes interconnected by a network structure, the system comprising:

at least one available data stream;

a plurality of receiver computer nodes on the computer network for receiving a selected data streams;

a transmitter computer node on the computer network accessing the selected data stream;

a plurality of multicast addresses within the network structure for providing a one-to-many communication path between the computer nodes on the network;

an assignment process within the transmitter node for dynamically assigning a select multicast address exclusively to the select data stream; and

a data transmitter within the transmitter node for transmitting the select data stream from the transmitter computer node to the select multicast address for receipt by a group of receiver nodes over the network structure.

11. The system of claim 10 wherein the data stream comprises a video program.

12. The system of claim 10 wherein the receiver computer nodes are client nodes and the transmitter computer node is a server node.

13. The system of claim 10 wherein the transmitter computer node is responsive to commands from the receiver computer nodes.

14. The system of claim 10 further comprising a resolution mechanism for resolving conflicts over multicast addresses selected by at least two server computer nodes.

15. The system of claim 10 further comprising a dedicated announcement address from the plurality of multicast addresses.

16. The system of claim 10 wherein there are a plurality of available data streams and each transmitter computer node is in communication with a subset of available data streams.

17. The system of claim 16 further comprising a selection process for selecting the data stream from the subset of available data streams.

18. A system for transmitting digital video data streams over a computer network having a plurality of computer nodes interconnected by a network structure, the system comprising:

a video source having access to at least one video program;

a plurality of client computer nodes on the computer network, at least one client computer node having an interest in a select video program at the video source;

a server computer node on the computer network in communication with the video source and responsive to commands from the client computer nodes;

a selection process within the server computer node for selecting the select video program from the video source;

a plurality of multicast addresses within the network structure for providing a one-to-many communication path between the computer nodes on the network;

an assignment process within the server computer node for dynamically assigning a multicast address exclusively to the select video program; and

a transmitter within the server computer node for transmitting the video program from the server computer node to the exclusive multicast address for receipt by a group of client computer nodes over the network structure.

19. The system of claim 18 wherein there are a plurality of server computer nodes and the assignment process resolves conflicts over multicast addresses concurrently selected by at least two server computer nodes.

20. The system of claim 19 wherein the computer nodes each have a unique respective network address on the network and the conflicts are resolved based on the network addresses of the conflicting server computer nodes.

21. The system of claim 18 further comprising a dedicated announcement address from the plurality of multicast addresses.

22. The system of claim 21 wherein the announcement address is monitored by all client computer nodes and all server computer nodes.

23. The system of claim 18 further comprising a database of video programs coupled to the plurality of client computer nodes and the server computer node, the database accessed and updated by the selection process and the assignment process.

24. In a network of computers interconnected by a network structure which includes a plurality of multicast addresses, and at least one server computer for transmitting a plurality of data streams over the network structure to a plurality of client computers, a method of dynamically assigning a multicast address to one data stream from a server computer, comprising the steps of:

receiving a request for a data stream transmission;

generating a list of unassigned multicast addresses that are not being used on the network;

selecting a candidate multicast address at random from the list of unassigned multicast addresses;

announcing, to a dedicated multicast address at a periodic interval, the candidate multicast address and the requested data stream, the announcing occurring at least twice during a first periodic interval occurring after a candidate multicast address is selected;

monitoring the dedicated multicast address for conflicts between the selected candidate multicast address and other announced multicast addresses;

resolving conflicts between the selected candidate multicast address and other announced multicast addresses to determine a transmission multicast address, conflicts being resolved based on network addresses; and

transmitting the data stream to the transmission multicast address for receipt by a group of client computers over the network structure.

25. A system for transmitting digital video data streams over a computer network having a plurality of computer nodes interconnected by a network structure, each computer node having a respective unique network address on the network, the system comprising:

a plurality of video sources having access to a plurality of video programs;

a plurality of client computer nodes on the computer network, at least one client computer node having an interest in a select video program;

a plurality of server computer nodes on the computer network in communication with the video sources and responsive to commands from the client computer nodes;

a selection process within a select server computer node for selecting the select video program from the video sources;

a plurality of multicast addresses within the network structure for providing a one-to-many communication path between the computer nodes on the network;

an assignment process within the select server computer node for dynamically assigning a multicast address exclusively to the select video program and resolving conflicts over multicast addresses concurrently selected by at least two server computer nodes, the conflicts being resolved based on the network addresses of the conflicting server computer nodes;

a dedicated announcement address from the plurality of multicast addresses used to announce assigned multicast addresses to all client computer nodes and all server computer nodes; and

a transmitter within the select server computer node for transmitting the select video program from the server computer node to the exclusive multicast address for receipt by a group of client computer nodes over the network structure.