Planning an 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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In the integrated Metasys BACnet/IP network architecture, all Metasys BACnet/IP devices, are directly integrated into the IT network. When the IP controllers are integrated directly into the IT network, it is the responsibility of the IT department to allocate the necessary IT resources required for the BAS network (for example, allocate the necessary VLANs and IP subnetworks to the BAS network) as well as configure the IT infrastructure to connect the BAS equipment to the IT infrastructure (that is, assign the physical switch ports to which the Metasys BACnet/IP devices will connect to the correct VLAN).

For ease of maintenance, it is recommended that IP addresses are assigned to devices in a consistent manner across subnetworks. At a minimum, reserve the following static IP addresses within each subnetwork:
  • A static IP address for the Switch Virtual Interface (SVI) for the VLAN. An SVI acts as the default gateway for all devices in the subnet and is required for the network engine to communicate with the Metasys server and with other network engine s in other VLANs. The host number of the SVI and the location of the SVI within the IT network is left to IT.
  • A static IP address for the network engine . The IP address of the network engine is statically assigned at the network engine although it could be dynamically assigned by the DHCP server using a static binding to the network engine MAC address, configured at the DHCP server.

For an Integrated Metasys BACnet/IP network, Johnson Controls recommends that a VLAN and IP subnetwork be allocated for each network engine and the BACnet/IP controller that it supervises. Johnson Controls recommends that the IP addresses of the IP controllers be dynamically assigned by way of DHCP. If the IP controllers are to be dynamically assigned, a small number of extra IP addresses (for example, 10) must be reserved in the DHCP scope so that they are available if one or more Metasys BACnet/IP devices need to be replaced. Johnson Controls recommends that all IP addresses for the Metasys BACnet/IP devices be allocated from a contiguous range in the middle of the subnetwork.

When possible, it is recommended that contiguous VLANs and IP subnetworks be allocated for the VLANs and subnetworks that comprise the Metasys BACnet/IP network.