Integrated Metasys BACnet/IP network - Metasys - LIT-12012458 - Field Device - 13.0

Metasys IP Networks for BACnet/IP Controllers Technical Bulletin

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For the Integrated Network architecture, the Metasys system is fully integrated with the IT network. All IP-based Metasys devices connect directly to IT access switches and are assigned IP addresses from the IT network’s address space.

The Integrated Network architecture is applicable when the IT department is able to allocate all the IP addresses as well as provided physical switch ports for all the IP-based BAS equipment. As was the case with the Converged Network architecture, IT has direct visibility to the IP controllers (for example, IT can ping them).

Grouping the network engine and the BACnet/IP controllers it supervises in the same VLAN/subnetwork as shown in Figure 1 allows the IP controllers supervised by the network engine to be easily identified by their IP address range. At the same time, it creates a network equivalent to an MS/TP-based system with BACnet routing enabled on all the network engine s. That is, a BACnet broadcast initiated by any network engine or IP controller will be seen by all other network engine s and IP controllers. Because each network engine is in a different VLAN, each network engine will be configured as a BBMD in a Metasys environment. This will result in BACnet broadcasts in any VLAN to be propagated to the other VLANs, in essence combining the smaller VLANs into one large VLAN from a BACnet broadcast perspective. Broadcasts for other protocols (for example, ARP and DHCP) will still be limited to the smaller VLANs. Placing all the network engine s together in their own separate VLAN as proposed in Segmented Metasys BACnet/IP network can help limit the scope of BACnet broadcasts, however it may require IT to configure directed broadcasts between the VLAN containing the network engine s and the VLANs containing the controllers, something IT may be unwilling to do.

The integrated architecture network is useful if the customer requires full control over the BAS network. It may also be useful if the BAS network has a physical extent similar to the IT network. It may be challenging to implement if the IT network expects an operational BAS network as a precondition for setting up the IT network (that is, the HVAC system has to be operational to cool and provide air filtration to the IDF closets and server rooms).

Figure 1. Integrated Metasys BACnet/IP network