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.

Abstract: A building control system is described that includes a building controller and a bridge. The building controller may control one or more portions of a building control system and may communicate with the bridge over a wired network. The bridge may be coupled to the building controller and may be configured to communicate with other remotely located building controllers via a wireless network. The bridge may provide a link between the wired communication of the local building controller and the wireless communication of the remotely located building controllers. The bridge may include a cache memory for storing data received from remotely located building controllers. In some cases, the data stored in the cache memory may be requested and received in advance of the data being requested by the local building controller.

Abstract: A building control system is described that includes a building controller and a bridge. The building controller may control one or more portions of a building control system and may communicate with the bridge over a wired network. The bridge may be coupled to the building controller and may be configured to communicate with other remotely located building controllers via a wireless network. The bridge may provide a link between the wired communication of the local building controller and the wireless communication of the remotely located building controllers. The bridge may include a cache memory for storing data received from remotely located building controllers. In some cases, the data stored in the cache memory may be requested and received in advance of the data being requested by the local building controller.

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.