User-Defined Flow ID

Stateful Flow Management
Platform
Napatech SmartNIC
Content Type
User Guide
Capture Software Version
Link™ Capture Software 12.7

The application can accelerate processing of received frames and generated flow info records using the user-defined flow ID.

Metadata and flow ID

Complete metadata for each flow shall be stored and managed in the host with the following considerations:
  • PCIe bandwidth: The amount of traffic to be delivered to the host is bound to the PCIe bandwidth.
  • Scalability: It is easier to extend memory in the host than in the SmartNIC.
  • Flexibility: The application can update each flow record in the host without updating the SmartNIC.

While complete flow metadata is stored in the host, absolutely necessary flow information is collected and stored in the SmartNIC flow table. To associate flow information in the SmartNIC flow table and in the host flow table, the user-defined flow ID is provided when frames and flow info records are delivered from the SmartNIC to the host as shown in the following figure.


Page-1 Sheet.40 Round Corner Rectangle Round Corner Rectangle.24 Round Corner Rectangle.25 Round Corner Rectangle.26 Round Corner Rectangle.27 Round Corner Rectangle.28 Round Corner Rectangle.29 Round Corner Rectangle.30 Round Corner Rectangle.31 L Shape Round Corner Rectangle.33 Round Corner Rectangle.34 L Shape.38 Rectangle Circle Application Application Can Flow table Sheet.4 Flow table Document Document.7 Document.8 Flow metadata Flow metadata Sheet.9 Host Host Can.12 Flow table Sheet.13 Flow table Document.14 Document.15 Document.16 Flow info record Flow info record Sheet.17 SmartNIC SmartNIC Rectangle.18 Flow manager Flow manager Rectangle.19 Flow ID Flow ID Rectangle.20 Frame Frame Simple Arrow Simple Arrow.22 Sheet.36 Sheet.37 Rectangle.38 Flow ID Flow ID Rectangle.39 Flow info record Flow info record

The flow ID of each flow can be programmed in the 64-bit id field of the NtFlow_s structure when learning a flow. The 64-bit flow ID can be configured as the pointer to a flow metadata in the host flow table. The SmartNIC includes the flow ID when delivering every frame and every flow info record to the application. The application can then easily access the associated flow metadata as the flow ID (of frames and flow info records) refers directly to the entry in the host flow table.
Note: The color1 field of dynamic packet descriptor 4 contains the flow ID.
Note: Set the ColorBits parameter to FlowID in NTPL to enable the flow ID of received frames.
See the following sections for more information about the flow ID.