Hash Key Type 10: 3-Tuple GREv0

Napatech Link-Capture™ Software Features
Platform
Intel® PAC
Napatech SmartNIC
Content Type
Feature Description
Capture Software Version
Link™ Capture Software 12.10

Hash key data

Hash key type 10 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 GREv0 key

For IPv4 packets, hash key data word 0 is always the IPv4 source address, and hash key data word 4 is always the IPv4 destination address. For IPv6 packets, hash key data words 0 – 3 are always the IPv6 source address, and hash key data words 4 – 7 are always the IPv6 destination address. This means that frames sent from IP address A to IP address B will generate a hash value different from frames sent from IP address B to IP address A (if address A and B are different).

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

Hash key data word 8 is always the GREv0 key.

For IPv4 packets, hash key data words 1 – 3, 5 – 7 and 9 are all zeros for hash key type 10. For IPv6 packets, hash key data word 9 is all zeros for hash key type 10.

Illustration for IPv4 packets

This figure illustrates hash key type 10 for IPv4 packets.

3-tuple GREv0 hash key for IPv4
Note: The Key field plus either the Checksum field or the Offset field must be present in order for the frame decoder to recognize a GREv0 packet.

Illustration for IPv6 packets

This figure illustrates hash key type 10 for IPv6 packets.

3-tuple GREv0 hash key for IPv6
Note: The Key field plus either the Checksum field or the Offset field must be present in order for the frame decoder to recognize a GREv0 packet.

Validity

Hash key type 10 is valid for frames containing an IPv4 packet or an IPv6 packet with a GREv0 packet as payload.