Remote Access Configuration for Multiple Buildings

Key Takeaways

• BASRTSX‑B supports up to 50 BBMD peers in BDT.
• Broadcast traffic shared across subnetted building networks.
• Single BASV‑3 can manage controllers in multiple sites.
• Adding new buildings requires only BDT entry updates.
• Secure remote access achieved without VPN complexity.

Pulse Analysis

Building owners increasingly demand unified control of HVAC, lighting, and security across dispersed campuses. Traditional approaches rely on VPNs or proprietary tunnels, which add latency and maintenance overhead. BACnet’s native broadcast model, however, struggles when subnets isolate traffic. Contemporary Controls addresses this gap by leveraging BBMD functionality within its BASRTSX‑B routers, allowing broadcast packets to be relayed as direct messages across routed IP networks. The Broadcast Distribution Table (BDT) stores peer IPs and subnet masks, supporting up to 50 remote sites and ensuring consistent device discovery.

The application note walks through a three‑building deployment where a BASV‑3 graphical supervisor in Building A centrally monitors controllers in Buildings B and C. By configuring the BASRTSX‑B in Building A as the primary BBMD and populating its BDT with the public IPs of partner BBMDs, BACnet/IP traffic flows seamlessly between subnets. Each building’s router bridges MS/TP and IP layers while performing BBMD duties, eliminating the need for separate broadcast repeaters. Expansion is straightforward: adding a new building only requires inserting its BBMD address into the existing BDT, preserving the broadcast distribution logic.

For facility managers, this architecture translates into lower total cost of ownership and faster rollout of new sites. Secure remote access is achieved through standard IP security controls rather than bespoke VPN configurations, reducing attack surface and simplifying compliance. As campuses grow and IoT devices proliferate, the ability to scale BACnet communications without sacrificing performance positions Contemporary Controls’ routers as a strategic component in modern, cloud‑enabled building automation strategies.