Queues and topics Messages can be transmitted via message queues, or be handled as topics using publish/subscribe semantics. Queues A message put on a message queue has only one receiver. If more than one application is listening to the same queue, only one of them can receive the message. The following WebSphere MQ queue connectors are available: • WebSphere MQ queue receiver input connector • WebSphere MQ queue sender output connector • WebSphere MQ reply queue sender output connector Topics Several publishing applications can publish messages for a topic, and several subscribing applications can receive the same message. The following WebSphere MQ queue connectors are available: • WebSphere MQ topic subscriber input connector • WebSphere MQ topic publisher output connector