structure but its order • FIFO, priority producer consumer queue 6 Message brokers Message broker: a system that connects event producers with event consumers. • It receives messages from the connects multiple producers to multiple consumers by organizing messages into topics. 7 Message Broker producer producer producer consumer consumer consumer - messages not removed after consumption handling, crashes or disconnects • Broker responsible for message durability • Asynchronous communication, i.e. producer only needs to receive ack from broker 9 Communication patterns (I) Load