Configuring Symmetric Trunk Hashing
When a specific network design or monitoring device requires that the same trunk port be selected for all packets in both directions in a connection, starting from release 6.1.0 NetVisor OS supports the Symmetric Trunk Hashing mode.
Note that:
- Symmetric hashing is agnostic to intrinsically unidirectional parameters, such as the ingress physical interface.
- Symmetric hashing mode is an alternative configuration to the default (asymmetric) mode.
- Configuring symmetric hashing does not require a switch restart.
- You can configure symmetric hashing on a single switch or on all switches of a fabric by prepending the command with switch*.
To configure symmetric hashing, use the following per-device system command:
CLI (network-admin@switch) > system-settings-modify <symmetric-hash | no-symmetric-hash>
Where, the symmetric-hash parameter enables symmetric trunk hashing on the switch. By default, this feature is disabled. If enabled, you can use the no-symmetric-hash parameter to disable it.
To configure symmetric hashing on all switches in a fabric, use the command:
CLI (network-admin@switch) > switch * system-settings-modify <symmetric-hash | no-symmetric-hash>
In case of GRE or IPSec traffic, ignoring the unidirectional GRE key or IPSec SPI fields in the symmetric hash computation can be configured using the CLI:
CLI (network-admin@switch) > system-settings-modify <hash-suppress-unidir-fields | no-hash-suppress-unidir-fields>
This feature is disabled by default, using the no-hash-suppress-unidir-fields parameter.
To verify the configuration details, use the system-settings-show command. Below is a sample output, where both symmetric-hash and hash-suppress-unidir-fields parameters are disabled.
CLI (network-admin@switch) > system-settings-show layout vertical
switch: switch
optimize-arps: off
lldp: on
policy-based-routing: off
optimize-nd: off
reactivate-mac: on
reactivate-vxlan-tunnel-mac: on
manage-unknown-unicast: off
manage-broadcast: off
block-loops: off
auto-trunk: on
auto-host-bundle: off
cluster-active-active-routing: on
routing-over-vlags: off
source-mac-miss: copy-to-cpu
igmp-snoop: use-l3
vle-tracking-timeout: 3
pfc-buffer-limit: 40%
cosq-weight-auto: off
port-cos-drop-stats-interval(s): disable
lossless-mode: off
snoop-query-stagger: no-stagger-queries
host-refresh: off
proxy-conn-retry: on
proxy-conn-max-retry: 3
proxy-conn-retry-interval: 500
manage-l2-uuc-drop: on
xcvr-link-debug: disable
fastpath-bfd: off
linkscan-interval: 150000
linkscan-mode: software
single-pass-l2-known-multicast: off
single-pass-flood: off
batch-move-mac-hw-group-for-vlan-only: off
memory-tracker: on
symmetric-hash: off
hash-suppress-unidir-fields: off