JMS unicast topic has a centralized  broker. RV is decentralized. All the rvd processes are equal in status. This is a little bit similar to
– email servers among Ivy League universities.
– file-sharing peer networks
RV is peer-to-peer; JMS is hub/spoke. Note in JMS request/response, “server” has ambiguous meanings. Here we mean the broker.
 You can load-balance the broker but the “outside world” views them as a single broker. It’s the Hub of hub/spoke. Scalability bottleneck.