Single IT VLAN-BAS access switches connected to the IT network with access ports - Metasys - LIT-12012458 - Field Device - 13.0

Metasys IP Networks for BACnet/IP Controllers Technical Bulletin

Document type
Technical Bulletin
Document number
LIT-12012458
Version
13.0
Revision date
2023-10-23
Product status
Active

An alternate approach to configuring trunks between the IT access switches and the BAS access switches is to connect both the network engine s and the BAS access switches directly to the IT network by way of access ports. For a BAS access switch to connect to an access port on an IT access layer switch, the uplink port of the BAS access switch must be configured as a routed port. The network engine s, which are in the same subnet as the BAS access switches’ routed port interfaces, must be connected directly to the IT access layer switches rather than to the BAS access switches. This approach requires additional IT switch ports (one for each of the network engine s) and physical drops from the IT closets where the IT access layer switches reside to the mechanical rooms where the network engine s reside, but is less burdensome for the customer’s IT department to configure. Figure 1 illustrates the network configuration of Figure 1 where both the network engine s and BAS access switches are connected to access ports in the IT network.

Figure 1. Single IT VLAN-BAS access switches connected to the IT network with access ports

The network engine s and BAS access switches still reside in IT VLAN 5 and the IP controllers still reside in BAS VLANs 10, 11, and 12. The IP addresses, default gateways, and route statements are also the same as for connecting the BAS access switches to the IT network by way of trunks. The two major differences are:

  1. The network engine s are physically connected to the IT access layer switches rather than the BAS access switches.
  2. The IT BAS subnet addresses of the BAS access switches are assigned to the routed ports on the BAS access switches rather than being configured as SVIs on the BAS access switches.

VLAN 5 must be propagated across IT network switches (access layer and distribution layer) which connect the BAS access switches and network engine s to each other.