Collection process
A collection process must be able to receive the flow information that is passing through multiple network elements within the data network.
Flow metric collection
Traffic on a data network can be perceived as a flow of data between two end-points that passes through network elements. For administrative or other purposes, it is beneficial to have the network elements observe these flows and report their characteristics to Network Performance Insight® to understand the network usage patterns.
- NetFlow cache
- A large amount of network information is condensed into a database of NetFlow information that is called the NetFlow cache. NetFlow can be configured to capture flows to the NetFlow cache. Typically, the NetFlow cache is constantly filling with flows and the router or switch searches the cache for flows that are terminated or expired and these flows are exported to the NetFlow collector.
- NetFlow exporter
- The NetFlow exporter sends flows that are in the cache to a NetFlow collector. NetFlow exporters are configured for Ingress interface traffic and Egress interface traffic or both.
- NetFlow collector
- NetFlow Collector receives and pre-processes flow data that is received from a flow exporter.
A flow is ready for export when it is inactive, when no new packets are received for the flow or if the flow is long lived (active) and lasts longer than the active timer. A flow is inactive if it has not received a packet for a specific duration that is longer than the inactive timeout value that is specified in the configuration. The flow record is deleted from the flow cache and an export record is generated, when the inactive timeout is triggered. By default, active timeout value is 30 minutes and inactive timeout value is 15 seconds.
The collector component in Network Performance Insight can then process and transform the data.
The collection process in Network Performance Insight is as follows:
