Reference Guide

520 | Equal Cost Multi-Path
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Related
Commands
hash-algorithm d
e
Select the d value for the ECMP, LAG, and NH hashing algorithm.
Syntax
hash-algorithm d value [linecard slot] [port-set number
]
Parameters
Defaults
None
Command Modes
CONFIGURATION
Command
History
Usage
Information
Deterministic ECMP sorts ECMPs in order even though RTM provides them in a
random order. However, the hash algorithm uses as a d the lower 12 bits of the
chassis MAC, which yields a different hash result for every chassis. This means that
for a given flow, even though the prefixes are sorted, two unrelated chassis will select
different hops.
FTOS provides a CLI-based solution for modifying the hash d to ensure that on each
configured system, the ECMP selection is same. When configured, the same d is set
for ECMP, LAG, and NH, and is used for incoming traffic only.
load-balance (C-Series and
S-Series)
d value
Enter the keyword followed by the d value.
Range: 0 to 4095
linecard slot
Enter the keyword linecard followed by the linecard slot number.
port-set number
Enter the keyword port-set followed by the linecard port-pipe
number.
Version 8.3.1.0 Introduced on E-Series.
Note: While the d is stored separately on each port-pipe, the same d is used across
all CAMs.
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 will not go to original
factory default setting.