NetFlow is a protocol that collects and analyzes network traffic data, such as source and destination IP addresses, ports, protocols, bytes, packets, and flows12.
NetFlow data can help identify the volume, type, and direction of network traffic, as well as the applications and hosts that are generating or consuming the most bandwidth12.
By collecting NetFlow data from the router, the network administrator can provide evidence to confirm that the recent network outages were caused by increased traffic from a specific application or host12.
Generating a network baseline report, exporting the firewall traffic logs, or plotting interface statistics for dropped packets may also provide some useful information, but they are not as specific or comprehensive as NetFlow data12. Reference:
1: CompTIA Network+ N10-008 Exam Cram, 6th Edition, Chapter 5: Network Traffic Analysis, p. 203-204
2: CompTIA Network+ N10-008 Cert Guide, 1st Edition, Chapter 9: Network Monitoring and Performance Optimization, p. 409-410