Hash Key Type 10: 3-Tuple GREv0

Napatech Link™ Capture Software Features

Platform
Napatech SmartNIC
Content Type
Feature Description
Capture Software Version
Link™ Capture Software 12.5

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

The hash key data is not sorted for hash key type 10. 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.

Page-1 Sheet.1 3-tuple GREv0 hash key 3-tuple GREv0 hash key Sheet.2 GREv0 packet header GREv0 packet header Sheet.3 IPv4 packet header IPv4 packet header Sheet.4 Ver. & IHL Ver. & IHL Sheet.5 Sheet.6 Sheet.7 Sheet.8 ToS ToS Sheet.9 Total length Total length Sheet.10 Identification Identification Sheet.11 F F Sheet.12 Fragment offset Fragment offset Sheet.13 Sheet.14 TTL TTL Sheet.15 Prot. Prot. Sheet.16 Header checksum Header checksum Sheet.17 Source address Source address Sheet.18 Destination address Destination address Sheet.19 Sheet.20 Options Options Sheet.21 0 0 Sheet.22 4 4 Sheet.23 8 8 Sheet.24 12 12 Sheet.25 16 16 Sheet.26 20 20 Sheet.38 0 0 Sheet.39 4 4 Sheet.40 8 8 Sheet.41 12 12 Sheet.42 16 16 Sheet.43 20 20 Sheet.44 Sheet.45 Sheet.46 Sheet.47 Sheet.48 Sheet.49 32-bit IPv4 source address 32-bit IPv4 source address Sheet.50 32-bit IPv4 destination address 32-bit IPv4 destination address Sheet.51 GREv0 key GREv0 key 45 degree single.1 45 degree single.27 45 degree single.54 Sheet.60 0 0 Sheet.61 1 1 Sheet.62 Hash key data word Hash key data word Sheet.63 2 2 Sheet.59 Flags, version and options Flags, version and options Sheet.65 Protocol type Protocol type Sheet.66 Checksum (optional) Checksum (optional) Sheet.67 Key (optional) Key (optional) Sheet.69 Payload Payload Sheet.70 Offset (optional) Offset (optional) Sheet.71 Sequence number (optional) Sequence number (optional) Sheet.72 Routing (optional) Routing (optional) Dynamic connector Sheet.73 0 0 Sheet.74 0 0 Sheet.75 0 0 Sheet.76 0 0 Sheet.77 0 0 Sheet.78 0 0 Sheet.79 3 3 Sheet.80 4 4 Sheet.81 5 5 Sheet.82 6 6 Sheet.83 7 7 Sheet.84 8 8
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.

Page-1 Sheet.85 3-tuple GREv0 hash key 3-tuple GREv0 hash key Sheet.86 GREv0 packet header GREv0 packet header Sheet.111 0 0 Sheet.112 4 4 Sheet.113 8 8 Sheet.114 12 12 Sheet.115 16 16 Sheet.116 20 20 Sheet.117 Sheet.118 Sheet.119 Sheet.120 Sheet.121 Sheet.124 GREv0 key GREv0 key 45 degree single.127 Sheet.132 Flags, version and options Flags, version and options Sheet.133 Protocol type Protocol type Sheet.134 Checksum (optional) Checksum (optional) Sheet.135 Key (optional) Key (optional) Sheet.136 Payload Payload Sheet.137 Offset (optional) Offset (optional) Sheet.138 Sequence number (optional) Sequence number (optional) Sheet.139 Routing (optional) Routing (optional) Dynamic connector.140 Sheet.152 8 8 Sheet.153 IPv6 packet header IPv6 packet header Sheet.154 Ver. & Pri. Ver. & Pri. Sheet.155 Sheet.156 Sheet.157 Sheet.158 Flow label Flow label Sheet.159 Length Length Sheet.160 Next header Next header Sheet.161 Hop limit Hop limit Sheet.162 Sheet.163 Source address Source address Sheet.164 Destination address Destination address Sheet.165 Sheet.166 0 0 Sheet.167 4 4 Sheet.168 8 8 Sheet.169 12 12 Sheet.170 16 16 Sheet.171 20 20 Sheet.172 24 24 Sheet.173 28 28 Sheet.174 32 32 Sheet.175 36 36 Sheet.176 40 40 Sheet.87 128-bit IPv6 source address 128-bit IPv6 source address Sheet.88 128-bit IPv6 destination address 128-bit IPv6 destination address Sheet.89 0, 1, 2 & 3 0, 1, 2 & 3 Sheet.90 Hash key data word Hash key data word Sheet.91 4, 5, 6 & 7 4, 5, 6 & 7 45 degree single.125 45 degree single.126
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.