# Define the Cluster

To define the cluster:

1. Go to the Cluster Elements form.

2. If no cluster currently exists, a Create Cluster button will be present in the form. Click Create Cluster to create a new cluster. The cluster is created and the local element is added as a member by default. If a cluster already exists, its name and Primary Node Identifier (PNI), if programmed, will be displayed at the top of the form.

NOTES

- To delete an existing cluster, you must delete all the elements from the Cluster Elements form. After you delete all the remote cluster elements you must remove the Local element last. The cluster is then automatically removed and the Create Cluster button with be available again.

- To add elements to an existing cluster, see Adding Cluster Elements.

- If there are any "MSL Server"-type network elements that are SDS sharing, creation of a second cluster is not allowed. Clicking the Create Cluster button will display the following message:

A cluster <cluster name> already exists. Creating a 2nd cluster is not allowed because some sharing network elements do not support multiple clusters.

3. Assign a name to the cluster.

4. If this is a large network that includes standalone elements, multiple clusters, or both, you must assign a unique 1- to 7-digit PNI to the cluster. If all the elements in your network are members of a single cluster, you do not need to assign PNIs to the cluster elements. Assign a PNI only if the cluster is connected in an MSDN/DPNSS network.

   CAUTION: The PNI will be changed on all elements in the network after you start sharing.

NOTES

- To change the name or PNI of an existing cluster, click Change. Enter the new name and PNI and then click Save.

- PNI is also referred to as a Node ID.

- If the controllers have 3300 ICP Release 6.0 or later software, you can also program the PNI from the Network Elements form for the local element if it does not already belong to a cluster.

5. Proceed to Adding Cluster Elements.