Hash Key Type 17: 3-Tuple GTPv1/GTPv2 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 17 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
  • 32-bit GTPv1 or GTPv2 TEID (tunnel endpoint identifier)

The hash key data for hash key type 17 is the same as for hash key type 16 (see Hash Key Type 16: 3-Tuple GTPv1/GTPv2) 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.

Hash key data word 8 is always the GTPv1 or GTPv2 TEID.

For IPv4 packets, hash key data words 1 – 3, 5 – 7 and 9 are all zeros for hash key type 17. For IPv6 packets, hash key data word 9 is all zeros for hash key type 17.

Algorithms for hash value generation for hash key type 17

The sorting algorithms for hash key type 17 are similar to the sorting algorithms 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 17 is valid for frames containing an IPv4 packet or an IPv6 packet with a GTPv1 or a GTPv2 packet as payload.