# Configure Federation

The federated caching feature federates cache data asynchronously across multiple geographically dispersed clusters. Cached data is federated across clusters to provide redundancy, off-site backup, and multiple points of access for application users in different geographical locations.

To configure federation:

1. If you have not already done so, in the Change Center of the Administration Console, click Lock & Edit (see Use the Change Center).
2. In the left pane of the Console, select Environment > Coherence Clusters.
3. In the Coherence Clusters table, select the Coherence cluster for which you want a configure federation.
4. Select the Configuration: Federation page.
5. Use the drop-down list to select a topology.

   Note:

   - When a topology is selected, a topology configuration is automatically created and named `Default-Topology`. The `Default-Topology` topology configuration is created and used if no other federation topology is specified in the cache configuration file.

   - When using federation, matching topologies must be configured on both the local and remote clusters. For example, selecting `none` for the topology in a local cluster and `active-active` as the topology in the remote cluster can lead to unpredictable behavior. Similarly, if a local cluster is set to use active-passive, then the remote cluster must be set to use passive-active.

6. From the Remote Participant section, enter the name of the remote cluster to which this cluster is being federated.
7. From the Remote Participant section, enter one or more hosts that are running managed Coherence servers on the remote cluster.
8. If required, change the cluster port of the remote cluster. The default cluster port is typically not changed.
9. To activate these changes, in the Change Center of the Administration Console, click Activate Changes.
   Not all changes take effect immediately—some require a restart (see Use the Change Center).