Users Guide

The stack-unit option is applicable with the lag-hash-align microcode only. Any other

microcode returns an error message as follows:

• Dell(conf)#hash-algorithm linecard 5 ip-sa-mask ff ip-da-mask

• % Error: This command is not supported in the current

microcode configuration

In addition, the linecard number ip-sa-mask value ip-da-mask value option

has the following behavior to maintain bi-directionality:

• When hashing is done on both IPSA and IPDA, the ip-sa-mask and ip-da-mask

values must be equal. (Single Linecard).

• When hashing is done only on IPSA or IPDA, Dell Networking OS maintains bi-

directionality with masks set to XX 00 for stack-unit 1 and 00 XX for stack-unit 2

(ip-sa-mask and ip-da-mask). The mask value must be the same for both

stack-units when using multiple stack-units as ingress (where XX is any value from

00 to FF for both stack-units). For example, assume that traffic is flowing between

linecard 1 and linecard 2:

• hash-algorithm linecard 1 ip-sa-mask aa ip-da-mask 00

• hash-algorithm linecard 2 ip-sa-mask 00 ip-da-mask aa

The different hash algorithms are based on the number of Port Channel members and

packet values. The default hash algorithm (number 0) yields the most balanced results

in various test scenarios, but if the default algorithm does not provide a satisfactory

distribution of traffic, use the hash-algorithm command to designate another

algorithm.

When a Port Channel member leaves or is added to the Port Channel, the hash

algorithm is recalculated to balance traffic across the members.

hash-algorithm ecmp

Change the hash algorithm used to distribute traffic flows 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.

Equal Cost Multi-Path (ECMP) 740