What is the difference between broadcast_address and broadcast_rpc_address in cassandra.yaml?

Question

GOAL: I am trying to understand the best way to configure my Cassandra cluster so that several different drivers across several different networking scenarios can communicate with it properly.

PROBLEM/QUESTION: It is not entirely clear to me, after reading the documentation what the difference is between these two settings: broadcast_address and broadcast_rpc_address as it pertains to the way that a driver connects and interacts with the cluster. Which one or which combination of these settings should I use with my node's accessible network endpoint (DNS record attainable by the client's/drivers)?

Here is the documentation for broadcast_address from datastax: (Default: listen_address)note The IP address a node tells other nodes in the cluster to contact it by. It allows public and private address to be different. For example, use the broadcast_address parameter in topologies where not all nodes have access to other nodes by their private IP addresses. If your Cassandra cluster is deployed across multiple Amazon EC2 regions and you use the EC2MultiRegionSnitch, set the broadcast_address to public IP address of the node and the listen_address to the private IP.

Here is the documentation for broadcast_rpc_address from datastax: (Default: unset)note RPC address to broadcast to drivers and other Cassandra nodes. This cannot be set to 0.0.0.0. If blank, it is set to the value of the rpc_address or rpc_interface. If rpc_address or rpc_interfaceis set to 0.0.0.0, this property must be set.

EDIT: This question pertains to Cassandra version 2.1, and may not be relevant in the future.

Answer 1

One of the users of #cassandra on freenode was kind enough to provide an answer to this question:

The rpc family of settings pertain to drivers that use the Thrift protocol to communicate with cassandra. For those drivers that use the native transport, the broadcast_address will be reported and used.

My test case confirms this.