Hash Key Type 13: 5-Tuple SCTP Sorted

Napatech Link™ Software Features

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Intel® PAC
Napatech SmartNIC
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Feature Description

Hash key data

Hash key type 13 is a 5-tuple where the hash key data is the contents of these packet header fields:

  • 32-bit IPv4 / 128-bit IPv6 source address
  • 32-bit IPv4 / 128-bit IPv6 destination address
  • 16-bit SCTP source port number
  • 16-bit SCTP destination port number
  • 32-bit SCTP verification tag

The hash key data for hash key type 13 is the same as for hash key type 12 (see Hash Key Type 12: 5-Tuple SCTP) except that it is sorted, so that the IPv4/IPv6 address with the highest value is used as hash key data word 0 / 0 – 3 and the IPv4/IPv6 address with the lowest value is used as hash key data word 4 / 4 – 7. This means that frames sent from IP address A to IP address B will generate the same hash value as frames sent from IP address B to IP address A.

Note: The source and destination addresses and ports can be swapped after sorting (see Tuple Swap).

If the IPv4/IPv6 source address is used as hash key data word 0 / 0 – 3, the SCTP source port number is placed in the upper 16 bits of hash key data word 8, and the SCTP destination port number is placed in the lower 16 bits of hash key data word 8. If the IPv4/IPv6 destination address is used as hash key data word 0 / 0 – 3, the SCTP destination port number is placed in the upper 16 bits of hash key data word 8, and the SCTP source port number is placed in the lower 16 bits of hash key data word 8.

Hash key data word 9 is always the SCTP verification tag.

For IPv4 packets, hash key data words 1 – 3 and 5 – 7 are all zeros for hash key type 13.

Algorithms for hash value generation for hash key type 13

The sorting algorithms for hash key type 13 are similar to the sorting algorithms for hash key type 9 (see Algorithm for hash value generation using hash key type 9 for IPv4 packets and Algorithm for hash value generation using hash key type 9 for IPv6 packets).

Validity

Hash key type 13 is valid for frames containing an IPv4 packet or an IPv6 packet with an SCTP packet as payload.