Administrator Guide

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.
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.
xor2 Use CRC16_BISYNC_AND_XOR2 — Upper 8 bits of CRC16-BISYNC and lower 8
bits of xor2.
xor4 Use CRC16_BISYNC_AND_XOR4 — Upper 8 bits of CRC16-BISYNC and lower 8
bits of xor4.
xor8 Use CRC16_BISYNC_AND_XOR8 — Upper 8 bits of CRC16-BISYNC and lower 8
bits of xor8.
xor16 Use CR16 — 16-bit XOR.
crc16cc Use CRC16_CCITT — 16-bit CRC16 using CRC16-CCITT polynomial.
crc32MSB Use CRC32_UPPER — MSB 16 bits of computed CRC32.
crc32LSB Use CRC32_LOWER — LSB 16 bits of computed CRC32.
Equal Cost Multi-Path (ECMP) 651