Network | Apache Kafka Documentation

The Network metric group contains per-node metrics regarding network activity. The metrics available are:

• Network in
• Network out

Even though disk I/O tends to be the main bottleneck most of the time, network can also be a bottleneck in Kafka performance. The network traffic metrics can help identify where the bottleneck lies.

Network in

This metric shows the difference between the number of the bytes received over the network since the last metric.

You can also get this metric through the Monitoring API  with the query param metrics=n::networkindelta

Network out

This metric shows the difference between the number of the bytes sent over the network since the last metric.

You can also get this metric through the Monitoring API  with the query param metrics=n::networkoutdelta