BACnet/IP Device Communication Isolation via Configurable UDP Ports

The patent introduces a BACnet Broadcast Management Device (BBMD) as an intermediary component that manages broadcast message distribution across IP subnets. The BBMD maintains a Broadcast Distribution Table (BDT) that tracks which subnets should receive which broadcast messages, effectively isolating device communications without requiring complex router configurations. This intermediary approach resolves the contradiction by providing network segmentation through a dedicated management device rather than through complex router logic.

The patent changes the operational parameters of BACnet devices by introducing configurable UDP port settings. Devices can be configured with specific local UDP ports for receiving broadcasts and specific IP addresses for sending unicast messages. This parameter-based control allows fine-grained isolation of communications without adding physical complexity, as the segmentation is achieved through configurable parameters rather than additional hardware complexity.

The patent extracts the multicast functionality from the core BACnet protocol and implements it as an optional enhancement only where needed. The BACnet/IP protocol stack includes optional multicast support that can be enabled or disabled based on network requirements. This extraction approach allows efficient message forwarding where multicast is implemented, while keeping the base protocol simple and avoiding mandatory complexity across all deployments.

The BBMD device is designed with multi-functionality, serving both as a broadcast management device and potentially as a multicast router. By consolidating these functions into a single device type, the patent reduces overall network complexity while maintaining the efficiency benefits of multicast where needed. The same device can handle both unicast and multicast traffic, reducing the need for specialized hardware.

The patent implements local quality by allowing different subnets to have different broadcast reception characteristics. The Broadcast Distribution Table (BDT) in the BBMD enables each subnet to selectively receive broadcasts based on local needs. Devices can be configured with specific local UDP ports that only accept broadcasts from designated subnets, creating localized broadcast domains that reduce overall network overhead while ensuring complete message delivery within each local domain.

The patent segments the broadcast domain into multiple isolated subdomains using IP subnets and BBMDs. Each subnet maintains its own broadcast traffic independently, with the BBMD acting as a controlled gateway between subnets. This segmentation prevents broadcast storms from propagating across the entire network while ensuring that each segment receives necessary broadcast messages for device discoverability and operation.