First the nine topics of BMP messages are defined and the SNAS log consumer program subscribes to them through the Kafka broker. The BMP parsed messages include notifications of router, peer, collector, bmp_stat, unicast_prefix, l3vpn, ls_node, ls_link, and ls_prefix. Once started, the log consumer waits for messages on one of these nine topics. When you connect kafka-console-producer.sh, you may send messages to the broker. However, the messages will not reach the log consumer unless they are of one of the nine topics. You may emulate the BMP messages by starting the kafka-console-producer.sh with one of the topics, as we did in the example with --topic openbmp.parsed.router flag. The received messages for these subscribed topics are pretty printed using to_json_pretty() in an if-else loop for each of these topics.