Dell C9000 series, Reference Manual

Page: 842 / 2286

Version Description
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.
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:
• 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
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.
hash-algorithm hg
To distribute traffic flows across different internal HiGig links, change the hash algorithm.
C9000 Series
Syntax
hash-algorithm hg { crc16 | xor1 | xor2 | xor4 | xor8 | xor16 |
crc16cc | crc32MSB | crc32LSB } linecard slot-id port-set port-pipe
Parameters
crc16 Use CRC16_BISYNC — 16-bit CRC16-bisync polynomial
(default).
xor1 Use CRC16_BISYNC_AND_XOR1 — Upper 8 bits of CRC16-
BISYNC and lower 8 bits of xor1.
Equal Cost Multi-Path (ECMP) 842