Hash Key Type 17: 3-Tuple GTPv1/GTPv2 Sorted

Napatech Link-Capture™ Software Features

Platform
Intel® PAC
Napatech SmartNIC
Content Type
Feature Description
Capture Software Version
Link™ Capture Software 12.9

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)

For hash key type 17, the source and destination IP addresses are XORed together. The XORed value is stored in hash key data word 0 / 0 – 3 whereas 4 / 4 – 7 are zeroed. 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.

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.