Juniper JN0-106 Exam - Topic 3 Question 7 Discussion

In Junos OS, there is a distinct difference between show commands and monitor commands. While show commands provide a static snapshot of the current state of the device or its interfaces at the moment the command is executed, monitor commands provide dynamic, real-time updates. To view live traffic statistics across all physical and logical interfaces, the correct command is monitor interface traffic.

When this command is executed, the CLI enters an interactive text-based interface (TUI) that displays a list of interfaces along with their input and output rates in bits per second (bps) and packets per second (pps). The display refreshes automatically (usually every few seconds), allowing an administrator to observe traffic spikes or drops as they occur without manually re-running a command. This is an invaluable tool for troubleshooting congestion or verifying that traffic is flowing as expected after a configuration change. Commands like show interfaces extensive provide significantly more detail---including error counters and physical layer parameters---but they are not real-time and require manual execution to update the statistics. The monitor interface traffic command simplifies the view to focus specifically on throughput metrics across the entire device. Reference: Operational Monitoring and Maintenance, Interface Monitoring, Real-time Statistics.