Changing The Hash Algorithm - Dell Z9000 Configuration Manual

[no] load-balance {ip-selection [dest-ip | source-ip]} | {mac [dest-mac |
source-dest-mac | source-mac]} | {tcp-udp enable} {ipv6-selection} {tunnel}|
{ingress-port}
You can select one, two, or all three of the following basic hash methods:
– ip-selection [dest-ip | source-ip] — Distribute IP traffic based on the IP destination or
source address.
– mac [dest-mac | source-dest-mac | source-mac] — Distribute IPV4 traffic based on the
destination or source MAC address, or both, along with the VLAN, Ethertype, source module ID
and source port ID.
– tcp-udp enable — Distribute traffic based on the TCP/UDP source and destination ports.
– ingress-port — Option to Source Port Id for ECMP/ LAG hashing.
– ipv6-selection— Set the IPV6 key fields to use in hash computation.
– tunnel— Set the tunnel key fields to use in hash computation.

Changing the Hash Algorithm

The load-balance command selects the hash criteria applied to port channels.
If you do not obtain even distribution with the load-balance command, you can use the hash-
algorithm command to select the hash scheme for LAG, ECMP and NH-ECMP. You can rotate or shift
the 12–bit Lag Hash until the desired hash is achieved.
The nh-ecmp option allows you to change the hash value for recursive ECMP routes independently of
non-recursive ECMP routes. This option provides for better traffic distribution over available equal cost
links that involve a recursive next hop lookup.
To change to another algorithm, use the second command.
• Change the default (0) to another algorithm and apply it to ECMP, LAG hashing, or a particular line
card.
CONFIGURATION mode
hash-algorithm | [ecmp{crc16|crc16cc|crc32LSB|crc32MSB|crc-upper|dest-ip |lsb
|xor1| xor2| xor4| xor8| xor16}|lag{crc16|crc16cc|crc32LSB|crc32MSB|xor1|
xor2|xor4|xor8|xor16}| seed ]
For more information about algorithm choices, refer to the command details in the IP Routing
chapter of the Dell Networking OS Command Reference Guide.
• Change the Hash algorithm seed value to get better hash value
Hash seed is used to compute the hash value. By default hash seed is chassis MAC 32 bits. we can also
change the hash seed by the following command.
CONFIGURATION mode
hash-algorithm seed {seed value}
• Change to another algorithm.
CONFIGURATION mode
hash-algorithm [ecmp{crc16|crc16cc|crc32LSB|crc32MSB|crc-upper|dest-ip|lsb|
xor1|xor2|xor4|xor8|xor16}]
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