For cluster redundancy with geographic separation with nodes in the same subnet the nodes may physically reside in the same location or in different locations. The latter case requires a VLAN bridging to logically interconnect them into the same subnet.
Although other configurations are possible, the configuration shown in the figure is recommended because it helps to avoid routing/packet forwarding loops, therefore minimizing the need for spanning tree protocol (which detects and controls packet forwarding loops). Additional redundant paths can be provided, but doing so results in a more complex LAN switch and router configuration.
In case of VLAN bridging special care needs to be taken by the network administrator to ensure that the network routers have rerouting capability of these virtual IP addresses to the access routers at either node of the geographically separated cluster.
All Lotus Sametime Unified Telephony virtual IP addresses have to exist in both locations.
Geographic Separated redundant Systems—Nodes in Same Subnet
Parent topic: Cluster Redundancy
Cluster Redundancy with Geographic Node Separation