Users Guide

The preceding anti-polarization techniques require some coordinated conguration of network nodes to solve the problem and these
techniques are not scalable when the number of tiers in the network is high. Flow based hashing specically addresses this using Macro
ow-based Hash function. It facilitates a dynamic hash function selection across dierent nodes in a network on a macro ow basis, thus
reducing unfair distribution of bandwidth between members and starvation.
Selection of Algorithms is available under ow-based-hashing enabling another level of randomness in hash selection. CLI to enable ow-
based hashing is shown in the given example:
Dell_GW1(conf)#hash-algorithm ecmp flow-based-hashing ?
crc16 CRC16_BISYNC - 16 bit CRC16-bisync polynomial(default)
crc16cc CRC16_CCITT - 16 bit CRC16 using CRC16-CCITT polynomial
crc32MSB CRC32_UPPER - MSB 16 bits of computed CRC32
crc32LSB CRC32_LOWER - LSB 16 bits of computed CRC32
xor1 CRC16_BISYNC_AND_XOR1 - Upper 8 bits of CRC16-BISYNC and lower 8 bits
of xor1
xor2 CRC16_BISYNC_AND_XOR2 - Upper 8 bits of CRC16-BISYNC and lower 8 bits
of xor2
xor4 CRC16_BISYNC_AND_XOR4 - Upper 8 bits of CRC16-BISYNC and lower 8 bits
of xor4
xor8 CRC16_BISYNC_AND_XOR8 - Upper 8 bits of CRC16-BISYNC and lower 8 bits
of xor8
xor16 CR16 - 16 bit XOR]
Example to view show hash-algorithm:
Dell(conf)#hash-algorithm ecmp flow-based-hashing crc16
Dell(conf)#end
Dell#show hash-algorithm
Hash-Algorithm
linecard 0 Port-Set 0
Seed 185270328
Hg-Seed 185282673
EcmpFlowBasedHashingAlgo- crc16
EcmpAlgo- crc32MSB LagAlgo- crc32LSB HgAlgo- crc16
312
Equal Cost Multi-Path (ECMP)