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.
When a member leaves or is added to the ECMP group, the hash algorithm is
recalculated to balance traffic across the members.
hash-algorithm seed
Select the seed value for the ECMP, LAG, and NH hashing algorithm.
Syntax
hash-algorithm seed
value
[linecard
slot
] [port-set
number
]
Parameters
seed
value
Enter the keyword
seed
then the seed value. The range is
from 0 to 4095.
linecard
slot
Enter the keyword
linecard
then the linecard slot number.
port-set
number
Enter the keywords
port-set
then the linecard port-pipe
number.
Defaults
none
Command
Modes
CONFIGURATION
Command
History
Version 9.2(0.0)
Introduced on the MXL 10/40GbE Switch IO Module.
Usage
Information
Deterministic ECMP sorts ECMPs in order even though RTM provides them in a
random order. However, the hash algorithm uses as a seed the lower 12 bits of the
chassis MAC, which yields a different hash result for every chassis. This behavior
means that for a given flow, even though the prefixes are sorted, two unrelated
chassis select different hops.
The Dell Networking OS provides a CLI-based solution for modifying the hash seed
to ensure that on each configured system, the ECMP selection is same. When
configured, the same seed is set for ECMP, LAG, and NH, and is used for incoming
traffic only.
Equal Cost Multi-Path (ECMP)
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