Hash Key Type 16: 3-Tuple GTPv1/GTPv2

Napatech Link-Capture™ Software Features
Platform
Napatech SmartNIC
Content Type
Feature Description
Capture Software Version
Link™ Capture Software 12.13

Hash key data

Hash key type 16 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 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).

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 16. For IPv6 packets, hash key data word 9 is all zeros for hash key type 16.

Illustration for IPv4 packets

This figure illustrates hash key type 16 for IPv4 packets.

3 - tuple GTPv 1 / GTPv 2 hash key GTPv 1 packet header IPv 4 packet header Ver . & IHL T o S Total l ength Identification F Fragment offset TTL Prot . Header checksum Source address Destination address Options 0 4 8 12 16 20 0 4 8 32 - bit GTPv 1 / GTPv 2 TEID Hash key data word Flags Type Total length TEID ( tunnel endpoint identifier ) Optional extended headers Payload GTPv 2 packet header 0 4 8 Flags Type Total length TEID ( tunnel endpoint identifier ) Sequence number Payload Spare Optional extended headers 12 32 - bit IPv 4 source address 32 - bit IPv 4 destination address 0 1 2 0 0 0 0 0 0 3 4 5 6 7 8

Illustration for IPv6 packets

This figure illustrates hash key type 16 for IPv6 packets.

3 - tuple GTPv 1 / GTPv 2 hash key GTPv 1 packet header 0 4 8 32 - bit GTPv 1 / GTPv 2 TEID Hash key data word Flags Type Total length TEID ( tunnel endpoint identifier ) Optional extended headers Payload GTPv 2 packet header 0 4 8 Flags Type Total length TEID ( tunnel endpoint identifier ) Sequence number Payload Spare Optional extended headers 12 8 IPv 6 packet header Ver . & Pri . Flow label Length Next header Hop limit Source address Destination address 0 4 8 12 16 20 24 28 32 36 40 128 - bit IPv 6 source address 128 - bit IPv 6 destination address 0 , 1 , 2 & 3 4 , 5 , 6 & 7

Validity

Hash key type 16 is valid for frames containing an IPv4 packet or an IPv6 packet with a GTPv1 or a GTPv2 packet as payload.