DELL S6000-ON User Manual

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Flex Hash and Optimized Boot-Up
This chapter describes the Flex Hash and fast-boot enhancements.
 
Flex Hash Capability Overview
This functionality is supported on the platform.
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 configure 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 must be operated with the Flex Hash mechanism.
Keep the following points in mind when you configure the flex hash capability:
• A maximum of eight flex hash entries is supported.
• A maximum of 4 bytes can be extracted from the start of the L4 header.
• The offset range is 0 – 30 bytes from the start of the L4 header.
• Flex hash uses the RTAG7 bins 2 and 3 (overlay bins). These bins must be enabled for flex hash to be 
configured.
• If you configure flex hash by using the load-balance ingress-port enable and the load-
balance flexhash commands, the show ip flow and show port-channel-flow commands 
are not operational. Flex hash settings and these show commands are mutually exclusive; only one of 
these capabilities can be functional at a time.
Configuring the Flex Hash Mechanism
This feature is supported on the platform.
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.
1.
In Dell Networking OS Release 9.3(0.0), you can enable bins 2 and 3 by using the load-balance 
ingress-port enable command in Global Configuration mode. To configure the flex hash 
functionality, you must enable these bins.
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Flex Hash and Optimized Boot-Up