Table of ContentsView in Frames

Supported cluster peer network topologies

To provide data protection, all of the intercluster LIFs of one cluster must be able to communicate with all of the intercluster LIFs of the cluster peer using pair-wise full-mesh connectivity. You need to understand how this connectivity works for different cluster topologies.

Pair-wise full-mesh connectivity applies only to the two clusters in the peer relationship. All of the intercluster LIFs of all the nodes in one cluster must be able to communicate with all of the intercluster LIFs of all the nodes in the other cluster. You cannot designate specific intercluster LIFs to work for specific cluster peer relationships.

Intercluster LIFs can be configured on different subnets on a single node or within a cluster. There are no restrictions on which networks intercluster LIFs may be configured or how many networks may be used for intercluster communication.

Using the concept of pair-wise full-mesh connectivity helps you to build more complex cluster peer topologies. Understanding how this connectivity works for two cluster, cluster cascade, and cluster fan-out or fan-in topologies will help you to create viable intercluster networks without adding intercluster networks that are unnecessary.

Intercluster networking between two clusters

Creating an intercluster network between two clusters is the basic cluster peer configuration. For example, you want to create an intercluster network between two clusters, Cluster A and Cluster B. Cluster A has two intercluster LIFs, A1 and A2, and Cluster B has two intercluster LIFs, B1 and B2. The LIFs are connected as follows:

Intercluster networking in a cluster cascade

When you connect three clusters in a cascade, all of the intercluster LIFs of the primary cluster must be able to communicate with all of the intercluster LIFs of the secondary cluster. Likewise, all of the intercluster LIFs of the secondary cluster must be able to communicate with all of the intercluster LIFs of the tertiary cluster. You do not need to create an intercluster network between the primary cluster and the tertiary cluster if you do not want to connect the two clusters in a cluster peer relationship.

For example, you want to create an intercluster network between Cluster A and Cluster B and an intercluster network between Cluster B and Cluster C. Cluster A has two intercluster LIFs, A1 and A2, Cluster B has two intercluster LIFs, B1 and B2, and Cluster C has two intercluster LIFs, C1 and C2. The intercluster LIFs between Cluster A and Cluster B are connected as follows:

The intercluster LIFs between Cluster B and Cluster C are connected as follows:

You might have a cluster cascade configured in which you want the tertiary cluster to connect to the primary cluster if something happens to the secondary cluster. An example is if you have a disaster recovery relationship between the primary cluster and the secondary cluster, and a backup relationship between the secondary cluster and the tertiary cluster, and you want the tertiary cluster to communicate with the primary cluster if something happens to the secondary cluster. If this configuration is what you want, then the intercluster LIFs of the tertiary cluster must be able to communicate with all of the intercluster LIFs of the primary cluster. Therefore, in addition to the connections previously mentioned, you would also have the following intercluster LIF connections between Cluster C and Cluster A:

Intercluster networking in a cluster fan-out or fan-in

When you connect clusters in a fan-out or fan-in configuration, the intercluster LIFs of each cluster that connects to the primary cluster must be able to communicate with all of the intercluster LIFs of the primary cluster. You do not need to connect intercluster LIFs between the remote clusters if the remote clusters do not need to communicate with each other.

For example, you want to create an intercluster network between Cluster A and Cluster B and an intercluster network between Cluster A and Cluster C. Cluster A has two intercluster LIFs, A1 and A2, Cluster B has two intercluster LIFs, B1 and B2, and Cluster C has two intercluster LIFs, C1 and C2. The intercluster LIFs between Cluster A and Cluster B are connected as follows:

The intercluster LIFs between Cluster A and Cluster C are connected as follows:

Cluster B is not connected to Cluster C.

If you do want a cluster peer relationship between two remote clusters in addition to the fan-in or fan-out configuration, then use the concept of pair-wise full-mesh connectivity to create an intercluster network between them.

Intercluster networking with a router

If you want to use intercluster networks for dedicated purposes, you can use a router. A router can forward data along the networks for which you configure the router without the need to connect to every intercluster LIF on the peer cluster. One example of how a router might be used is if you want to designate one intercluster network for local back up and you want to designate another intercluster network to a storage service provider. In the following example, if you are not peering Cluster B and Cluster C, then the router can disallow all communication between the intercluster LIFs of Cluster B and Cluster C.