Service Manual

load-balance exhash
Specify the parameters for the Flex Hash mechanism, such as whether IPv4 or IPv6 packets must be subject to Flex Hash
functionality, a unique protocol number, the oset of hash elds 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.
Syntax
load-balance flexhash ipv4/ipv6 ip-proto <protocol number> <description
string> offset1 <offset1 value> [offset2 <offset2 value>]
To disable the Flex hash settings, use the no load-balance flexhash ipv4/ipv6 ip-proto
protocol number command.
Parameters
ipv4 Denotes whether Flex Hash needs to be enabled for IPv4 packets.
ipv6 Denotes whether Flex Hash needs to be enabled for IPv6 packets.
protocol number
Represents the Outer IPv4 protocol eld in case of IPv4 packets, and the Outer
IPv6 next header eld in case of IPv6 packets.
The ipv4/ipv6 keyword and the IP protocol value are used as keys to identify if a
duplicate ex hash conguration is already present. Duplicate ex hash
conguration is not possible. To change an existing ex hash conguration, you
must delete the existing ex hash attribute and congure the ex attribute afresh.
description string A description string is followed by the protocol number to enable you to associate
the protocol number with the protocol name in an easily-identiable way. For
example, for a protocol number of 254, you can specify the description as RRoCE.
oset1 value Specify the byte oset from the start of the L4 header from which the 2-byte data
is extracted and be used in hash computation. You must enter the oset as an even
number. The oset range is 0 – 30 bytes from start of L4 header.
oset2 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 oset as an
even number. The oset range is 0 – 30 bytes from start of L4 header.
Default None
Command Modes CONFIGURATION mode
Command History
Version Description
9.3(0.0) Introduced on the S6000 platform.
9.2(1.0) Introduced on the Z9500.
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 trac ow is contained in the L4 header. The elds in the L2 and
L3 headers are not sucient to distinguish the ows. Therefore, the elds in the L4 header are processed
when hashing is performed for packets over LAG and ECMP links. The Flex Hash functionality enables you
to congure a packet search key and matches packets based on the search key. When a packet matches
the search key, two 16-bit hash elds 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 oset of hash elds from the start of the
L4 header, which contains a ow identication eld.
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Flex Hash and Optimized Boot-Up