Hash-Algorithm Ecmp - Dell Force10 Z9000 Reference Manual

hash-algorithm ecmp

Change the hash algorithm used to distribute traffic flows across an ECMP (equal-cost multipath routing) group.
C-Series, E-Series, S-Series, Z-Series
Term heading Description heading
Syntax hash-algorithm ecmp {crc-upper} | {dest-ip} | {lsb}
To return to the default hash algorithm, use the no hash-algorithm ecmp command.
Parameters
crc-upper
dest-ip
lsb
Defaults
Command Modes CONFIGURATION
Command History
Version 8.3.11.1
Version 8.1.1.0
Version 7.6.1.0
Version 7.5.1.0
Usage Information The hash value calculated with the hash-algorithm command is unique to the entire chassis.
The default ECMP hash configuration is crc-lower. This takes the lower 32 bits of the hash key
to compute the egress port and is the "fall-back" configuration if you have not configured
anything else.
The different hash algorithms are based on the number of ECMP group members and packet
values. The default hash algorithm yields the most balanced results in various test scenarios,
but if the default algorithm does not provide satisfactory distribution of traffic, use this
command to designate another algorithm.
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NOTE: You cannot separate LAG and ECMP, but you can use different algorithms across
chassis with the same d. If LAG member ports span multiple port-pipes and line cards, set
the d to the same value on each port-pipe to achieve deterministic behavior.
NOTE: If the hash algorithm configuration is removed, Hash d does not go to the original
factory default setting.
Uses the upper 32 bits of the key for the hash computation. Default:
crc-lower.
Uses the destination IP for ECMP hashing. Default: enabled.
Returns the LSB of the key as the hash. Default: crc-lower.
• crc-lower
• dest-ip enabled
Introduced on the Z9000.
Introduced on the E-Series ExaScale.
Introduced on the S-Series.
Introduced on the C-Series.