Service Manual
When a Port Channel member leaves or is added to the Port Channel, the hash algorithm is recalculated to
balance trac across the members.
hash-algorithm ecmp
Change the hash algorithm used to distribute trac ows across an ECMP (equal-cost multipath routing) group.
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 Uses the upper 32 bits of the key for the hash computation. The default is crc-
lower.
dest-ip Uses the destination IP for ECMP hashing. The default is enabled.
lsb Returns the LSB of the key as the hash. The default is crc-lower.
Defaults
• crc-lower
• dest-ip enabled
Command Modes CONFIGURATION
Command History
This guide is platform-specic. For command information about other platforms, refer to the relevant Dell
Networking OS Command Line Reference Guide.
The following is a list of the Dell Networking OS version history for this command.
Version Description
9.8(0.0) Introduced on the S3048-ON and S4048-ON.
8.3.19.0 Introduced on the S4820T.
8.3.11.1 Introduced on the Z9000.
8.3.7.0 Introduced on the S4810.
8.1.1.0 Introduced on the E-Series ExaScale.
7.6.1.0 Introduced on the S-Series.
7.5.1.0 Introduced on the C-Series.
Usage Information The hash value calculated with the hash-algorithm command is unique to the entire chassis. The
default ECMP hash conguration is crc-lower. This command takes the lower 32 bits of the hash key to
compute the egress port and is the “fall-back” conguration if you have not congured anything else.
The dierent 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 trac, use this command to designate another algorithm.
530
Equal Cost Multi-Path (ECMP)