Exam N10-008 topic 1 question 152 discussion

A. CPU usage would be one of the key metrics to measure the impact of NetFlow on a Layer 3 switch as it would indicate if the switch is experiencing any increased processing workload due to the feature being enabled. It would be a good idea to also monitor the memory usage of the switch to ensure that it does not run out of memory when NetFlow is enabled.

- Enabling NetFlow on a Layer 3 switch can have a significant impact on the switch's CPU usage, as the switch needs to process and analyse the network traffic flows. By graphing the switch's CPU usage using SNMP, the network administrator can measure the impact of the NetFlow feature on the switch's performance and identify any potential performance issues.

Bandwidth is already being used for network traffic to flow, CPU usage is going to be increased to measure that bandwidth usage.

NetFlow A packet analyzer can be used to measure network traffic statistics but trying to record each frame imposes a heavy processing overhead on the network tap or mirror port. Collecting just the packet metadata, rather than the whole packet payload, reduces the bandwidth required by the sniffer. Technologies such as Cisco’s NetFlow (cisco.com/c/en/us/products/ios-nx-os-software/ios-netflow/index. html) gather traffic metadata only and report it to a structured database

GPT selects (A): "The metric that the network administrator should graph using SNMP to BEST measure the impact of enabling NetFlow on a Layer 3 switch is (A) CPU usage. Enabling NetFlow on a network device, like a Layer 3 switch, can generate additional processing overhead as it collects and analyzes flow data. Monitoring the CPU usage will provide insights into how much computational resources are being used by the NetFlow feature. If the CPU usage increases significantly after enabling NetFlow, it could indicate that the feature is impacting the switch's performance and potentially causing issues. Options (B) Temperature, (C) Electrical consumption, and (D) Bandwidth usage are important metrics to monitor, but they might not provide direct insights into the impact of the NetFlow feature on the switch's performance. Monitoring CPU usage will give a clearer indication of any impact on the switch's processing capabilities."

I thought bandwidth as well, a NetFlow collector aggregates flows from multiple exporters. A large network can generate huge volumes of flow traffic and data records, so the collector needs a high bandwidth network link and substantial storage capacity.

Another bad question to confuse overthinkers. Netflow could help analyze Bandwidth required, but here I guess they want CPU as the answer. Difficult to guess. Best strategy is to dumb down to the level of the question creator and it could be a challenge

Answer is A: Before enabling NetFlow on a network element, the CPU utilization is the first parameter to monitor. Enabling NetFlow and exporting the flow records with NetFlow version 5 increases the CPU utilization by about 15 percent on average, up to a maximum of 25 percent on some platforms.