Reference Guide

load-balance flexhash
Configure Flex hash operation, such as whether IPv4 or IPv6 packets are processed by the Flex hash functionality, a unique
protocol number, the offset of hash fields from the start of the L4 header to be used for hash calculation, and a meaningful
description to associate the protocol number with the name.
Z9500
Syntax
load-balance flexhash ipv4/ipv6 ip-proto protocol-num description offset1
value [offset2 value]
To disable the Flex hash configuration, enter the no load-balance flexhash ipv4/ipv6 ip-
proto protocol number command.
Parameters
ipv4 Specifies that Flex hash must be enabled for IPv4 packet processing.
ipv6 Specifies that Flex hash must be enabled for IPv6 packet processing.
protocol-num The specified protocol number identifies the outer IPv4 protocol field in IPv4
packets and the outer IPv6 next-header field in IPv6 packets.
The ipv4/ipv6 keyword and the IP protocol value are used as keys to identify if a
duplicate flex hash configuration is already enabled. Duplicate flex-hash
configuration is not supported. To change an existing flex hash configuration, you
must delete the existing flex hash attribute and re-configure the flex attribute.
description Enter a text description to associate the protocol number with the protocol name in
an easily identifiable way. For example, if the protocol number is 254, you can enter
RRoCE as the description.
offset1 value Specify the byte offset from the start of the L4 header from which the 2-byte data
is extracted and used in hash computation. You must enter the offset as an even
number. The offset range is 0 to 30 bytes from start of L4 header.
offset2 value (Optional) Specify the additional 2 bytes that must be extracted from the start of
the L4 header to be used for hash computation. You must enter the offset as an
even number. The offset range is 0 to 30 bytes from start of L4 header.
Default None
Command Modes CONFIGURATION mode
Command
History
Version 9.2.1.0 Introduced on the Z9500 switch.
Version 9.3.0.0 Introduced on the S6000 platform.
Usage
Information
With the introduction of various overlay technologies such as network virtualization using generic routing
encapsulation (NVGRE) segments and Routable Remote Direct Memory Access (RRDMA) over
Converged Ethernet (RRoCE), information related to a traffic flow is contained in the L4 header. The
fields in the L2 and L3 headers are not sufficient to distinguish the flows. Therefore, the fields in the L4
header are processed when hashing is performed on packets over LAG and ECMP links. The Flex hash
functionality enables you to configure a packet search key and matches packets based on the search key.
When a packet matches the search key, two 16-bit hash fields are extracted from the start of the L4
header and provided as inputs (bins 2 and 3) for RTAG7 hash computation. You must specify the offset of
hash fields from the start of the L4 header, which contains a flow identification field.
You can cause the system to include the fields present at the offsets that you define (from the start of
the L4 header) as a part of LAG and ECMP computation. Also, you can specify whether the IPv4 or IPv6
packets are processed with the Flex hash functionality.
Example
Dell(conf)# load-balance flexhash ipv4 ip-proto 1 desc offset1 1 offset2 2
Flex Hash 561