Final answer:
NetFlow is a Cisco proprietary protocol used for monitoring all IP traffic on network interfaces where it is enabled, useful for traffic analysis and network performance monitoring.
Step-by-step explanation:
NetFlow is a proprietary traffic monitoring protocol from Cisco that tracks all IP traffic crossing any interface where it is enabled. This protocol is designed to collect metadata about the IP traffic such as the source and destination IP addresses, class of service, and the cause of discard if the packet is dropped. By enabling NetFlow on a network interface, administrators can gain insight into traffic patterns and network performance.
NetFlow data is often used for a variety of purposes including network traffic analysis, capacity planning, and security monitoring. An important aspect of this protocol is its ability to scale to manage large amounts of traffic data without a significant performance impact on the network devices. For example, NetFlow can help network administrators identify high-bandwidth users, detect security threats like Distributed Denial of Service (DDoS) attacks, and optimize network performance by identifying bottlenecks or inefficient traffic patterns.