In earlier releases, the bridges relationship was between MACs and the switch port. The port bridges MAC relationship is made regardless of the type of the MAC, physical or virtual. This resulted in a connection creation issue for the Hosts with ESX Server installed connected to a switch and routers with HSRP/VRRP configured connected to the switch.
In this release, Port instead of Bridges forms a new relationship called VirtualBridges with virtual MACs. During discovery, if a switch port is associated with a MAC address that matches the VirtualMACPattern configured in the tpmgr_param.conf file, a VirtualBridges relationship is created for the switch port. The VirtualBridges relation is also formed for Systemless MAC irrespective of the VirtualMACPattern.
Systemless MAC will have virtualbridges relationship with the port. The default VirtualMACPattern has the VMware specific MACs, VRRP, and HSRP MACs. By removing the VirtualMACPattern from the tpmgr-param.conf file, the Bridges relationship gets established.
The IP Manager User Guide provides more information on VirtualMACs.