E.3 Planning a Virtual IP Network Implementation

In theory, any state-of-the-art routing protocol could be used for the virtual IP network. This section describes how to set up the virtual router using the OSPF (Open Shortest Path First) routing protocol because it is a commonly used protocol.

For the OSPF routing protocol, define an OSPF Area ID to use for the BCC-enabled resources in a business continuity cluster. All nodes of every peer cluster in a given business continuity cluster need to use the same OSPF Area ID. When deploying multiple business continuity clusters, use a different OSPF Area ID for each one.

For your LAN routers, you must define the OSPF Area ID to be used for each of your business continuity clusters. For guidelines about OSPF Area IDs, see Section E.3.1, Routing Protocol. The LAN routers are also where you define and handle the propagation of the routes to services that are using virtual IP addresses.

Do not use a cluster node as a general purpose router. Ensure that a default gateway is properly set up, and the default route of the cluster node is configured accordingly.

Redistribute any routing changes for the cluster resources to your routing infrastructure, but do not redistribute routing changes somewhere in the LAN/WAN to the cluster nodes.

Define an IP address range for your BCC-enabled resources. The IP addresses must be unique across all peer clusters. When deploying multiple business continuity clusters, use a different IP address range for each of them.

For example, you can specify an IP address range for each peer cluster that accommodates the nodes and the master IP address of the cluster:

• Cluster 1: 10.10.10.0/24
• Cluster 2: 10.10.20.0/24
• Cluster 3: 10.10.30.0/24
• Cluster 4: 10.10.40.0/24

You can specify a different range to be used for all cluster resources in the business continuity cluster:

• Resources: 10.10.50.nnn/32

To use a virtual IP address in a business continuity cluster, you must see a host mask. To understand why, consider the fact that each service in a clustered environment must have its own unique IP address, or a unique virtual IP address. Furthermore, consider that each virtual IP address belongs to a virtual IP network whose route is being advertised by a single node within a cluster. Because Novell Cluster Services can migrate a service and its virtual IP address from one node to another, the virtual IP network must migrate to the same node as the service. If multiple virtual IP addresses belong to a given virtual IP network, one of two events must occur:

Neither of these situations is desirable. Fortunately, the use of host masks remedies both.