Usage Scenario
To define target flows and ensure measurement accuracy, run the flow command to configure target flow characteristics.
One or more fields in IP headers can be specified to identify target flows. The field can be the source IP address or prefix, destination IP address or prefix, protocol type, source port number, destination port number, or ToS. The more fields specified, the more accurately flows can be identified. Specifying as many fields as possible is recommended to maximize the measurement accuracy.
Configuration Impact
An IP FPM instance can have only one target flow configured, either unidirectional or bidirectional. A bidirectional target flow is logically two unidirectional flows in opposite directions.
- If the target flow in an IP FPM instance is unidirectional, only forward can be specified.
- If the target flow in an IP FPM instance is bidirectional, two situations are available:
- If the bidirectional target flow is symmetrical, you can specify bidirectional to configure the bidirectional target flow characteristics. By default, the characteristics specified are used for the forward flow, and the reverse of those are used for the backward flow. Specifically, the source and destination IP addresses and port numbers specified for the forward flow are used respectively as the destination and source IP addresses and port numbers for the backward flow.
- If the bidirectional target flow is asymmetrical, you must configure forward and backward in two command instances to configure the forward and backward flow characteristics.
Precautions
Target flows in different IP FPM instances cannot have the same characteristics. The forward and backward target flows in an IP FPM instance cannot have the same characteristics neither.