Data flow services, commonly known as NetFlow, is a network protocol that collects IP traffic information as records and sends them to a collector for traffic analysis. It is a new technology that is gradually being refined and improved.
The primary function of NetFlow lies in its ability to provide service providers and enterprises with information for network capacity planning, trend analysis, and data prioritization. This technology can also be used for IP-based billing applications and Service Level Agreement (SLA) verification services.
1. How NetFlow Works: NetFlow first records the data of the initial IP packet, such as the IP protocol type, Type of Service (ToS), interface identifier, etc. Then, to match and count data more effectively, NetFlow allows subsequent data to be transmitted within the same data flow, while applying their respective services, such as security filtering, QoS policies, and traffic shaping. Real-time data is stored in the NetFlow cache and can be retrieved through read operation commands.
2. Building upon NetFlow, Cisco later proposed NetFlow Policy Routing (NPR) technology. This technology, based on Cisco IOS services, provides traffic planning and IP pre-classification functions, offering an efficient, high-performance NetFlow mechanism for policy routing.
Since NPR also supports the CEF architecture, it can be used on distributed platforms.
3. The NetFlow capabilities of distributed switches and NetFlow collector tools can monitor application traffic, measure traffic performance changes over time, and assist with capacity planning to ensure I/O resources are allocated to applications appropriately based on their needs. If IT administrators want to monitor the performance of application traffic running in virtual environments, they can enable traffic monitoring in distributed switches.
4. NetFlow on distributed switches can be enabled at the port group level, individual port level, or uplink level. When configuring NetFlow at the port level, administrators should select the NetFlow override tag, which ensures that traffic can still be monitored even when port group level NetFlow is disabled.
5. During the setup process, you can control different parameters. The IP address and port in the collector settings should be configured based on the relevant information of the collector tool installed in your environment. Advanced setting parameters allow you to control traffic timeout and sampling rate. To change the amount of information collected for a certain type of traffic, you can modify the sampling rate.
6. VDS IP address configuration is very useful when you want the collector tool to see all traffic information as part of a VDS IP address, rather than as individual host management network IP addresses. Without entering a VDS IP address, the collector tool will provide detailed traffic information under each host management network IP address.
7. The impact of the NetFlow feature on the CPU depends entirely on the volume of traffic in your environment and the rate at which that traffic operates. If you believe there is a lot of traffic in your environment and are concerned about CPU resources, you can use the controls provided