Users Guide

Equal cost multi-path
ECMP is a routing technique where next-hop packet forwarding to a single destination occurs over multiple best paths. OS10 uses a
hashing algorithm to determine the next-hop when you enable ECMP. The hashing algorithm makes hashing decisions based on values in
various packet elds as well as some internal values.
• Congure the hash algorithm in CONFIGURATION mode.
hash-algorithm ecmp crc
Change hash algorithm
OS10(config)# hash-algorithm ecmp crc
Load balancing
RTAG7 is a hashing algorithm that load balances trac within a trunk group in a controlled manner. To eectively increase the bandwidth of
ECMP routes, trac is balanced across member links. The balancing is performed by using the RTAG7 hashing, which is designed to have
the member links used eectively as the trac prole gets more diverse.
The RTAG7 hash scheme generates a hash that consists of two parts:
• The rst part is primarily generated from packet headers to identify micro-ows in trac. By default, all listed parameters are enabled
for load balancing except the ingress port.
OS10# show load-balance
Load-Balancing Configuration For LAG and ECMP:
----------------------------------------------
IPV4 Load Balancing : Enabled
IPV6 Load Balancing : Enabled
MAC Load Balancing : Enabled
TCP-UDP Load Balancing : Enabled
Ingress Port Load Balancing : Disabled
IPV4 FIELDS : source-ip destination-ip protocol vlan-id l4-destination-port l4-source-port
IPV6 FIELDS : source-ip destination-ip protocol vlan-id l4-destination-port l4-source-port
MAC FIELDS : source-mac destination-mac ethertype vlan-id
TCP-UDP FIELDS: l4-destination-port l4-source-port
• The second part comes from static physical conguration such as ingress and egress port numbers.
You can change the hash eld to generate load balancing based on any parameters using the load-balance command.
ECMP commands
hash-algorithm
Changes the hash algorithm that distributes trac ows across ECMP paths and the LAG.
Syntax
hash-algorithm {ecmp | lag} crc
Parameters
• ecmp — Enables ECMP hash conguration.
• lag — Enables LAG hash conguration for L2 only.
• crc — Enables CRC polynomial for hash computation.
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