GLOBAL BROADCAST COMMUNICATION SYSTEM

• US 20090257431A1
• Filed: 04/15/2008
• Published: 10/15/2009
• Est. Priority Date: 04/15/2008
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Honnappa, Arun, Guntipalli, Giri B., Gadura, Nitin, Ramanathan, ShunmugaPriya, Krishuasamy, Balaji, Korubilli, Kalyani
• Granted Patent: US 8,174,962 B2
• Time in Patent Office: Days
• US Class Current: 370/389
• CPC Class Codes: H04W 4/06 Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services

Abstract

A global broadcast communication network system having a plurality of subnets. The system may incorporate a building and automation control network (BACnet) protocol. Each subnet may have a one active BACnet broadcast management device (BBMD) for broadcasting messages to other subnets. Also, there may be BIP (BACnet over IP) devices, such as controllers, tools and stations, in the subnets. One of the BIP devices in each subnet may be configured or enabled as a passive BBMD. If there is a failure of the active BBMD in a subnet, then the passive BBMD of the same subnet may detect the failure and assume the role of the active BBMD to minimize or eliminate possible disruption of communication across the subnets. Each BBMD may have and maintain a broadcast distribution table (BDT) which contains information about BBMDs in other subnets. Each BBMD may provide updated BDT information to the other BBMDs.

Claims

1. A global broadcast communication system comprising:

two or more subnets; and

wherein;

at least one subnet comprises;

an active broadcast management device; and

a passive broadcast management device;

a passive broadcast management device assumes a role of an active broadcast management device if the active broadcast management device fails; and

a broadcast management device is for sending broadcast messages across the subnets.

2. The system of claim 1 wherein:

the broadcast management device comprises a broadcast distribution table; and

the broadcast distribution table contains information about other broadcast management devices.

3. The system of claim 2, wherein the passive broadcast management device reads and updates its broadcast distribution table from the broadcast distribution table of the active broadcast management device of the same subnet.

4. The system of claim 3, wherein the active broadcast management device is for providing unicasts of global building automation and control network (BACnet) broadcast messages among the subnets.

5. The system of claim 4, wherein a subnet comprises BACnet over Internet protocol (BIP) components.

6. The system of claim 5, wherein an active broadcast management device is enabled in a subnet if the respective subnet comprises more than one BIP component.

7. The system of claim 5, wherein a BIP component of a subnet is configured as a passive broadcast management device for the subnet.

8. The system of claim 2, wherein the passive broadcast management device of a subnet is for monitoring a status of the active broadcast management device of the same subnet and for ensuring that its broadcast distribution table is in synch with the broadcast distribution table of the active broadcast management device.

9. The system of claim 1, wherein the passive broadcast management device assumes the role of the active broadcast management device nearly immediately after the active broadcast management device fails.

10. The system of claim 1, wherein if a failed active broadcast management device of a subnet returns to a non-failed condition, then the passive broadcast management device leaves the role of the active broadcast management device if the active broadcast management device resumes the role of the active broadcast management device for the subnet.

11. A method for improving reliability of broadcast communication messages, comprising:

providing two or more subnets;

providing an active broadcast management device in a subnet of the two or more subnets;

providing two or more communication devices in the subnet; and

enabling one of the communication devices in the subnet as a passive broadcast management device; and

wherein the passive broadcast management device is for assuming a role of the active broadcast management device.

12. The method of claim 11, wherein communication across the subnets is effected by the active broadcast management device.

13. The method of claim 12, wherein if the active broadcast management device fails, the passive broadcast management device sufficiently promptly assumes the role of the active broadcast management device so as to prevent a significant disturbance of communication across the subnets.

14. The method of claim 13, wherein a broadcast management device maintains a broadcast distribution table which contains information about broadcast management devices in the subnets.

15. The system of claim 14, wherein:

an active broadcast management device is a building automation and control network (BACnet) active broadcast management device for providing a unicast of global BACnet broadcast messages across the subnets; and

communication devices in a subnet are BACnet over Internet protocol (BIP) components.

16. A system having reliable global broadcast communication, comprising:

a plurality of subnets;

an active broadcast management device in a subnet of the plurality of subnets; and

a passive broadcast management device in the subnet; and

wherein;

if the active broadcast management device of the subnet exhibits a failure, then the passive broadcast management device of the same subnet assumes a role as the active broadcast management device for the subnet; and

communication across the plurality of subnets is achieved with a building and automation control network (BACnet) protocol over Internet protocol (BIP).

17. The system of claim 16, wherein if an active broadcast management device of a subnet fails, then a passive broadcast management device of the subnet detects a failed active broadcast management device and automatically assumes the role as the active broadcast management device to enable broadcast communication of the subnet with other subnets of the plurality of subnets.

18. The system of claim 17, wherein if the active broadcast management device becomes no longer failed, then the passive broadcast management device relinquishes the role as the active broadcast management device if the active broadcast management device resumes the role as the active broadcast management device for the subnet.

19. The system of claim 16, wherein:

the passive broadcast management device monitors a status of the active broadcast management device;

and

upon detection of a change of status of the active broadcast management device to one of not being capable to assume the role as the active broadcast management device, then the passive broadcast management device nearly immediately assumes the role as the active broadcast management device; and

one broadcast management device is or assumes the role of the active broadcast management device for one subnet.

20. The system of claim 16, wherein a broadcast communication device maintains a broadcast distribution table for providing and/or receiving information, respectively, to and/or from broadcast distribution tables of broadcast management devices.