Users Guide

linecard number
(OPTIONAL) : Enter the keyword linecard then the linecard slot number.
port-set number
(OPTIONAL) Enter the keyword port-set then the port-set slot number.
Defaults 0 for hash-algorithm value on TeraScale and ExaScale IPSA and IPDA mask value is FF for a line card.
Command Modes CONFIGURATION
Supported Modes Full–Switch
Command History
Version Description
9.9(0.0) Introduced on the FN IOM. Added ow-based-hashing support for hashing on ECMP.
9.2(0.0) Introduced on the MXL 10/40GbE Switch IO Module.
Usage Information To ensure that CRC is not used for LAG, set the default hash-algorithm method on ExaScale systems. For
example,hash-algorithm ecmp xor lag checksum nh-ecmp checksum.
To achieve the functionality of hash-align on the ExaScale platform, do not use CRC as a hash-algorithm method.
The hash value calculated with the hash-algorithm command is unique to the entire chassis. The hash
algorithm command with the line card option changes the hash for a particular line card by applying the mask
specied in the IPSA and IPDA elds.
The line card option is applicable with the lag-hash-align microcode only (refer to CAM Prole Commands). Any
other microcode returns an error message as follows:
• Dell(conf)#hash-algorithm linecard 5 ip-sa-mask ff ip-da-mask ff
• % 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, the Dell Networking OS maintains bi-directionality with masks set
to XX 00 for line card 1 and 00 XX for line card 2 (ip-sa-mask and ip-da-mask). The mask value must be
the same for both line cards when using multiple line cards as ingress (where XX is any value from 00 to FF for
both line cards). For example, assume that trac is owing 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 dierent 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 trac, 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
trac across the members.
On TeraScale, if you do not enter the keyword ECMP or LAG, the Dell Networking OS assumes it to be common for
both. If the keyword ECMP or LAG is entered separately, both should fall in the range of 0 to 23 or 24 to 47 since
compression enable/disable is common for bothTeraScale and ExaScale support the range 0-47. The default for
ExaScale is
24.
468
Equal Cost Multi-Path (ECMP)