StrongKey Tellaro Appliances are always installed in a clustered configuration for HA in a production environment. All the servers function in a master-master where any server can receive transactions and will asynchronously replicate data records between all other nodes in the cluster.
When KeyAppliance software stack gets installed on StrongKey Tellaro appliances, it includes a ZeroMQ (ZMQ) module which is responsible for replication of database objects among nodes in the cluster.
ZeroMQ (also known as ØMQ, 0MQ, or zmq) are ports that work in alliance with Transmission Control Protocol (TCP ports). ØMQ ports are like mailboxes with routing. ØMQ helps speed up the process as opposed to traditional messaging systems. Other tools can be used for group messaging and multi casting but ØMQ is a tool for doing this process more efficiently since these ports can can bind to multiple ports and protocols concurrently.
In the appliance there are 3 ports used by the server:
| Port Number | Use for the Port |
| 7001 | The 7001 port is used by the Publisher for multi-casting all persisted objects to the cluster. Multi-casting (or group messaging) allows the host to send a single packet to multiple destinations over the IP network. Note that all sensitive data is always encrypted even before persisted. |
| 7002 | The 7002 port is used to receive acknowledgements from the cluster nodes. |
| 7003 | The 7003 port is used by the BacklogProcessor (BLP) to send objects to specific nodes that did not acknowledge they received and persisted replicated objects. |