Technical Considerations for a Serviceguard Cluster that Spans Multiple IP Subnets, July 2009

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When the IP Monitor is configured for a package subnet, you are not required, for network
monitoring purposes, to have a standby interface for the package subnet. However, a standby
interface for the package subnet provides high availability for the package subnet.
For more information about the IP Monitor, see “Monitoring LAN Interfaces and Detecting Failure: IP
Level” in Chapter 3 of the “Managing Serviceguard” manual, which you can find on
http://docs.hp.com under High Availability  Serviceguard.
Examples of network configuration requirements
Example 1: Dual heartbeat subnet requirement
The following diagram, Figure 5, shows a minimum supported cross-subnet cluster configuration with
dual heartbeats.
Figure 5 – Minimum Supported Configuration on a multi-site cross-subnet cluster with dual heartbeat subnets (one dedicated
heartbeat subnet and one shared heartbeat/package subnet)
In this example, one heartbeat subnet is dedicated and the other is a shared heartbeat/package
subnet.
 Heartbeat subnet 5.1.1.0 on Datacenter 1 and heartbeat subnet 5.2.1.0 on Datacenter 2 are fully
routed to each other.
 Heartbeat subnet 5.1.2.0 on Datacenter 1 and heartbeat subnet 5.2.2.0 on Datacenter 2 are fully
routed to each other.
 Each heartbeat subnet is routed on its own separate physical network. This implies that the routing
configuration is such that any IP packet targeted to 5.2.1.0 must be routed out of the interface