Hash Key Type 15: 3-Tuple GTPv0 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 15 is a 3-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 GTPv0 flow label

The hash key data for hash key type 15 is the same as for hash key type 14 (see Hash Key Type 14: 3-Tuple GTPv0) 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.

The GTPv0 flow label is always placed in the lower 16 bits of hash key data word 8. The rest of this word is all zeros.

For IPv4 packets, hash key data words 1 – 3, 5 – 7 and 9 are all zeros for hash key type 15. For IPv6 packets, hash key data word 9 is all zeros for hash key type 15.

Algorithms for hash value generation for hash key type 15

The sorting algorithms for hash key type 15 are similar to the sorting algorithm for hash key type 5 (see Algorithm for hash value generation using hash key type 5 for IPv4 packets and Algorithm for hash value generation using hash key type 5 for IPv6 packets).

Validity

Hash key type 15 is valid for frames containing an IPv4 packet or an IPv6 packet with a GTPv0 packet as payload.