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Version Description
7.7.1.1 Added the nh-ecmp option.
6.5.1.0 Added the line card option on TeraScale only.
6.3.1.0 Added support for ECMP and LAG on TeraScale only.
Usage
Information
To ensure that CRC is not used for LAG, set the default hash-algorithm method.
For example,hash-algorithm ecmp xor lag checksum nh-ecmp
checksum.
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 specified in the IPSA and IPDA
fields.
The line-card 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 ff
• % Error: This command is not supported in the current
microcode configuration
In addition, the linecard slot-id 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 system 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 traffic is flowing
between line card 1 and line card 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.
Equal Cost Multi-Path (ECMP)
743