Hash-Algorithm Hg - Dell C9000 Series Reference Manual

Networking command-line reference guide

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Usage Information To ensure that CRC is not used for LAG, set the default 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 specified in the IPSA and IPDA fields.

In addition, the linecard slot-id ip-sa-mask value ip-da-mask value

option has the following behavior to maintain bidirectionality:

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

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 hg

To distribute traffic flows across different internal HiGig links, change the hash algorithm.

C9000 Series

hash-algorithm hg {crc16 | xor1 | xor2 | xor4 | xor8 | xor16 |

crc16cc | crc32MSB | crc32LSB} linecard slot-id port-set port-pipe

Added support for ECMP and LAG on TeraScale only.

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 bidirectionality

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

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

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

Use CRC16_BISYNC — 16-bit CRC16-bisync polynomial

Use CRC16_BISYNC_AND_XOR1 — Upper 8 bits of CRC16-

BISYNC and lower 8 bits of xor1.

Equal Cost Multi-Path (ECMP)

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