IP multicasting in mesh TDMA satellite networks

• US 6,894,990 B1
• Filed: 10/13/2000
• Issued: 05/17/2005
• Est. Priority Date: 10/13/2000
• Status: Expired due to Term

• Current Assignee: ViaSat Incorporated
• Original Assignee: ViaSat Incorporated
• Inventors: Rempe, Steven P., Rao, Ashok K., Agarwal, Anil K., Ramaswamy, Sreenivas
• Primary Examiner(s): Nguyen, Chau
• Assistant Examiner(s): LEE, CHI HO A
• Application Number:
  US09/689,738
• Time in Patent Office: 1,677 Days
• Field of Search: 370/321, 370/337, 370/347, 370/340, 370/392, 370/432, 370/316, 370/322, 370/326, 370/328, 370/329, 370/336, 370/341, 370/349, 370/389, 370/390, 370/477, 370/498, 370/408, 370/238, 455/427, 455/428, 455/430, 455/445, 455/560, 455/518, 709/249
• US Class Current: 370/321
• CPC Class Codes: H04B 7/18584 Arrangements for data networking, i.e. for data packet routing, for congestion control data switching networks H04L12/00
• CPC Class Codes: H04L 12/1836 with heterogeneous network architecture
• 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 45/04 Interdomain routing, e.g. hierarchical routing
• CPC Class Codes: H04L 45/16 Multipoint routing
• CPC Class Codes: H04L 45/42 Centralised routing

Abstract

A system and method for supporting Internet Protocol (IP) Multicast in mesh TDMA satellite networks using a centralized route server architecture, which conserves link bandwidth and minimizes delay. Individual satellite terminals perform forwarding of multicast IP traffic to destination terminals based on information provided by the route-server. Multicast routing protocols need to be supported only at the route server, thus minimizing the CPU and memory resources required at the end terminals. Channel capacity for multicast traffic can be statically or dynamically assigned and takes full advantage of the broadcast nature of the medium.

Claims

1. A system for offing Internet Protocol (IP) multicast services in mesh TDMA satellite networks, said system comprising:

a plurality of terminals for providing said IP multicast services, each terminal being connected to at least one local router;

a route server in communication with a plurality of said local routers for establishing and maintaining routing information for said plurality of said local routers including routing information for repeated multicast calls through the network, based on updated information sent from individual said local routers; and

a controller operative to allocate broadcast bursts to said terminals based on requests from said terminals via said route server.

2. A system according to claim 1, wherein said controller is operative to allocate said broadcast bursts through the selection of at least one slot in a TDMA frame to be used only for broadcast communication.

3. A system according to claim 1, wherein said IP multicast services are initiated between said terminals via said route server and said controller, and are thereafter maintained between said terminals.

4. A system according to claim 1, wherein said controller is operative to allocate said broadcast bursts in response to a request from one of said terminals, and thereafter all of said terminals listen to said broadcast bursts.

5. A system according to claim 4, wherein said controller is operative to allocate said broadcast bursts using an algorithm known as the Burst Time Plan (BTP) generation algorithm.

6. A system according to claim 4, wherein said controller allocates said broadcast bursts using point-to-point, multicast, or broadcast transmissions.

7. A system according to claim 4, wherein said controller dynamically allocates said broadcast bursts according to user demand for multicast services, and further wherein a maximum multicast capacity is preconfigured by a network operator.

8. A system according to claim 4, wherein said allocation occurs at least one of when the multicast transmission is setup, and after the multicast transmission is setup, based on changes in multicast traffic volume, as reported by terminals to said controller.

9. A system according to claim 1, wherein said terminals exchange routing information with said route server.

10. A system according to claim 9, wherein said terminals transmit and receive said broadcast bursts based on said routing information.

11. A system according to claim 10, wherein said routing information includes a multicast routing protocol which is run by said route server.

12. A system according to claim 11, wherein said multicast routing protocol is DVMRP.

13. A system according to claim 11, wherein said multicast routing protocol is PIM-SM.

14. A method for offering Internet Protocol (IP) multicast services in a mesh TDMA satellite network having a plurality of terminals connected to local routers, and a master terminal, said method comprising:

establishing and maintaining routing information for said plurality of local routers, in a common route server coupled to said master terminal, by exchanging information between each of said local routers and said common route server for repeated multicast calls through the network;

responding to a request for multicast services by assigning at least one slot in a TDMA frame to one of a plurality of terminals and updating said routing information in said common route server based on said assignment;

broadcasting said IP multicast services over said at least one slot according to said routing information in said common route server.

15. A method according to claim 14, further comprising:

transmitting IP multicast packets from a source to said route server;

forwarding said routing information to said terminals;

broadcasting said IP multicast packets from said route server to said terminals;

broadcasting said IP multicast packets between said terminals via said at least one slot;

refining a receiving set of said terminals, which receive said IP multicast packets, based on prune messages received at said route server from a non-receiving set of said terminals, which do not receive said IP multicast packets.

16. A method according to claim 14, further comprising:

sending join messages from a router to a rendezvous point (RP) via said route server;

updating said routing information in said route server based on said join messages;

broadcasting said updated routing information to said terminals;

unicasting IP multicast packets to said rendezvous point; and

multicasting said IP multicast packets from said rendezvous point based on said updated routing information.