For internode communication, Cassandra uses a protocol called gossip. To improve bootstrapping the gossip process for new nodes joining the cluster, you can configure an additional seed node so that each Cassandra datacenter in your cluster has one seed node. With this approach, when you add a node to a Cassandra datacenter, this node communicates with the seed node of the datacenter instead of the main seed node.

If you configure an additional seed node, you must repeat this procedure on all nodes in the cluster. You must also ensure that you use the same list of additional seed nodes on all nodes in the cluster.