Napatech Network Adapters support different distribution schemes depending on the type of adapter:
- Distribution per port: All frames captured on a physical port are fed to the same server buffer. Maybe the traffic is merged with traffic from another port, and maybe the traffic has been filtered or sliced, but the traffic is still fed to the same server buffer, and hence to the same CPU core.
- Distribution per traffic type: Different traffic types are fed to different server buffers. This can e.g. be protocols recognized by the Frame Decoder or specified by bit patterns. Different CPU cores will each operate on their type of frame, but the frames may come from different physical ports on the adapter.
- Distribution by flows: The distribution of frames is based on hash keys, ensuring that frames from the same traffic flow will always go to the same CPU cores. If frame flow distribution is used, the hash key value range used for the distribution is divided equally between the number of CPU cores specified.
- Combinations of the above: Most Napatech Network Adapters can combine some or all of the distribution schemes mentioned in up to 32 different server buffers.
The different packet distribution schemes allow different ways of load balancing a multi-CPU server. Some multi-protocol applications, such as SNORT, may be running on each CPU processing only parts of the total captured traffic. Specialized applications for handling only one type of frames (e.g. mail, VoIP or HTTP) could also be put on each CPU, and have the Napatech Network Adapter filter out the needed protocols to the needed applications.