`HashDestination`

Display Hash Destination

HashDestination

Shortest form: hd.

Hash-destination tools, usually abbreviated hd. hd dest get asks which ECMP member, LAG member or Higig-trunk member a packet with the given header fields would be sent to. hd ethertype manages which EtherTypes take part in ECMP and trunk hashing.

Type the keywords in full. eth also works for ethertype, info for dest, and calc for get. Group= takes ECMP, LAG, HGT or, for hd dest get, ANY. The built-in help writes Module=<modid> for hd dest get, but the shell accepts Modid= and rejects Module=.

hd dest get and hd ethertype show are read-only. hd ethertype mode, add and delete change ECMP and LAG hashing behind SONiC’s back.

Describe a packet by its ingress port and header fields. The shell prints the flags it used and, for each group, the member the packet would go to: an ECMP egress object ID, or a trunk member as 0x<gport> (tp[<i>]=<port>,tmod[<i>]=<mod>). CalcInfo prints the computed UDP source port or LBID instead. The answer is calculated by the SDK; no packet is sent. Read-only.

Port= takes a port number, as the built-in help’s <port#> says; with a port name such as Port=ce0 the shell only prints the usage, as the first example shows. On a SONiC switch, trunk show gives the trunk ID of a PortChannel to use as GID with Group=LAG.

Hardware-validated — Which ECMP member would a TCP flow from ce0 use?

drivshell> hd dest get Group=ECMP Port=ce0 SrcIp=192.0.2.1 DestIp=198.51.100.1 PROTocol=6 L4SrcPort=1234 L4DstPort=80
Usage (HashDestination): Usages:
  hd ethertype mode [Group=ECMP|LAG|HGT] [Eligible=T|F] [Inner=T|F]
  hd ethertype add [Group=ECMP|LAG|HGT] [EtherType=<0xHHHH>]
  hd ethertype delete [Group=ECMP|LAG|HGT] [EtherType=<0xHHHH>]
  hd ethertype show [Group=ECMP|LAG|HGT]
  hd dest get [Group=ECMP|LAG|HGT|ANY] [GID=<id>]
           [Port=<port#>] [Module=<modid>] [Untagged=T|F]
           [DestMac=<mac>] [SrcMac=<mac>] [Vlan=<vid>] [EtherType=<0xHHHH>]
           [SrcIp=<ip4>] [DestIp=<ip4>] [SIp6=<ip6>] [DIp6=<ip6>]
           [PROTocol=<Pid>] [L4SrcPort=<num>] [L4DstPort=<num>]
           [FwdReason=Unicast|Ipmc|L2mc|Bcast|Dlf]
           [CalcInfo=UDP_SOURCE_PORT|LBID]

Hardware-validated — A trunk query that the SDK rejects

drivshell> hd dest get Group=LAG GID=1 Port=1 SrcIp=192.0.2.1 DestIp=198.51.100.1 PROTocol=6 L4SrcPort=1234 L4DstPort=80
HashDestination: Invalid parameter

With Port= given as a number the command is parsed, but the SDK rejects the query with Invalid parameter even for an existing trunk (trunk 1 is SONiC’s PortChannel on xe0–xe2). A form that hd dest get accepts on Trident 3 has not been found.

HashDestination ethertype show [Group=<ECMP|LAG|HGT>]

For each group (or the one given), print whether the listed EtherTypes are eligible or ineligible for hashing, the EtherTypes, and their count. Read-only.

On a SONiC switch every list is empty (OUTER Ineligible Cnt:0). Without Group=, Trident 3 prints all three groups and then fails with HashDestination: Invalid parameter; the lines above the error are still valid.

Hardware-validated

drivshell> hd ethertype show
  ECMP:
    EtherType: OUTER Ineligible    Cnt:0

  LAG:
    EtherType: OUTER Ineligible    Cnt:0

  HGT:
    EtherType: OUTER Ineligible    Cnt:0

HashDestination: Invalid parameter

Failed to execute the diagnostic command. Error: Operation failed.

Hardware-validated — One group only

drivshell> hd ethertype show Group=ECMP
  ECMP:
    EtherType: OUTER Ineligible    Cnt:0

HashDestination ethertype mode [Group=<ECMP|LAG|HGT>] [Eligible=<T|F>] [Inner=<T|F>]

Choose whether the listed EtherTypes are the ones that are hashed (Eligible=T) or the ones that are not, and whether inner headers are used. Changes the ASIC.

Unvalidated

drivshell> hd ethertype mode Group=LAG Eligible=T

HashDestination ethertype add [Group=<ECMP|LAG|HGT>] [EtherType=<0xHHHH>]

Add an EtherType to a group’s list. Changes the ASIC.

Unvalidated

drivshell> hd ethertype add Group=ECMP EtherType=0x8847

HashDestination ethertype delete [Group=<ECMP|LAG|HGT>] [EtherType=<0xHHHH>]

Remove an EtherType from a group’s list. Changes the ASIC.

Unvalidated

drivshell> hd ethertype delete Group=ECMP EtherType=0x8847

Built-in help

Usages:
    hd ethertype mode [Group=ECMP|LAG|HGT] [Eligible=T|F] [Inner=T|F]
    hd ethertype add [Group=ECMP|LAG|HGT] [EtherType=<0xHHHH>]
    hd ethertype delete [Group=ECMP|LAG|HGT] [EtherType=<0xHHHH>]
    hd ethertype show [Group=ECMP|LAG|HGT]
    hd dest get [Group=ECMP|LAG|HGT|ANY] [GID=<id>]
             [Port=<port#>] [Module=<modid>] [Untagged=T|F]
             [DestMac=<mac>] [SrcMac=<mac>] [Vlan=<vid>] [EtherType=<0xHHHH>]
             [SrcIp=<ip4>] [DestIp=<ip4>] [SIp6=<ip6>] [DIp6=<ip6>]
             [PROTocol=<Pid>] [L4SrcPort=<num>] [L4DstPort=<num>]
             [FwdReason=Unicast|Ipmc|L2mc|Bcast|Dlf]
             [CalcInfo=UDP_SOURCE_PORT|LBID]