Dynamic Hash Key Selection

Multi-CPU Distribution

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IntelĀ® PAC
Napatech SmartNIC
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User Guide

Dynamic hash key selection

It is possible to dynamically select the hash key to use based on the protocol type for the frame. For example, a 5-tuple hash key can be applied to TCP, UDP and SCTP frames, and a 2-tuple hash key can be applied to any other IP frames, which do not contain the protocol and port information necessary for the 5-tuple hash key. To specify this, the HashMode command (see DN-0449) is issued using the Priority and Type parameters.

Dynamic hash key selection example

In this NTPL example, all IP packets are to be delivered to the same set of streams, while preserving as much of the flow information as possible. That is, for packets containing protocol and port information, the more specific 5-tuple hash key applies. For other IP packets only the IP address information is used for specifying the flow:

HashMode[Priority=0; Layer4Type=UDP,TCP,SCTP] = Hash5Tuple
HashMode[Priority=1; Layer3Type=IP] = Hash2Tuple
Assign[StreamId=(0..7)] = All