show forwarding configuration

Description

Displays the configured selection criteria for ECMP routes and load-sharing group ports and the hardware table settings, including the configured and current hash algorithm and dual-hash settings.

Syntax Description

This command has no arguments or variables.

Default

N/A.

Usage Guidelines

The output of this command displays the following information:

Configured hash algorithm—The hash algorithm configured on the switch. After the configuration is saved and the switch is rebooted, the switch uses this hash algorithm.
Current hash algorithm—The hash algorithm currently used by the switch.
Configured dual-hash setting—Whether the dual-hash feature is configured ‘on‘ or ‘off‘ on the switch. After the configuration is saved and the switch is rebooted, the switch uses this setting.
Current dual-hash setting—Whether the dual-hash feature is currently ‘on‘ or ‘off‘ on the switch.
Dual-Hash recursion level—The current dual-hash recursion level; default is ‘1.‘
Sharing criteria—Current selection criterion used for ECMP route sharing as well as for load-sharing groups. Specifies which Layer 3 and Layer4 information is used in the sharing hash algorithm. For more information, see the description for the configure forwarding sharing [L3 | L3_L4] command.
Group Table Compression—Whether the group table compression is currently ‘on‘ or ‘off‘ on the switch.
Switching mode—Whether the switching mode is currently set to ‘cut-through‘ or ‘store-and-forward.‘
Fabric flow control—Whether flow control fabric configuration is set to ‘auto‘ or ‘off.‘

It is possible for the values of the configured and the current hash, or the configured and current dual-hash settings to be different. For example, if you modified the hash algorithm and have not saved the configuration and rebooted the switch, the values might be different. In this situation, the switch also displays the following message:

 NOTE: A save and reboot are required before the configured hash will take effect

Example

The following command displays the hardware forwarding algorithm configured on the switch:

show forwarding configuration

The following is sample output from this command on a BlackDiamond 8800 series switch:

BD-8810.1 # show forwarding configuration
L2 and L3 Forwarding table hash algorithm:
Configured hash algorithm:              crc32
Current hash algorithm:                 crc32
L3 Dual-Hash configuration:  (Applies only to "c" and "xl"-series HW)
Configured setting:                     on
Current setting:                        on
Dual-Hash Recursion Level:              1
Hash criteria for IP unicast traffic for L2 load sharing and ECMP route sharing
Sharing criteria:                      L3_L4
IP multicast:
Group Table Compression:                on
IP multicast:       
    Group Table Compression:            on      
    Lookup-Key                          SourceIP, GroupIP, VlanId       
Switch Settings:       
    Switching mode:                     store-and-forward       
Fabric Flow Control:       
    Fabric Flow Control:                auto

In addition to the data shown above, on BlackDiamond X8 series switches the following lines appear at the end of the output:

Fabric Hash Slot-1:
Packet Algorithm:
Dynamic mode
Eligibility
or
Fabric Hash Slot-2:
Packet Algorithm:
crc16-ccitt
seed: 0x12345678
or
Fabric Hash Slot-5:
Source-port

For BlackDiamond X8 series switches, when the switch fabric hash is set to Default, there is no printed output for the related slot.

Dual-hash information appears only on BlackDiamond X8 series switches and BlackDiamond 8800 series switches.

Fabric flow control information appears only on BlackDiamond X8 series switches, BlackDiamond 8800 series switches, SummitStack, and Summit X460, X670, and X770 switches.

History

This command was first available in ExtremeXOS 11.3.2.

The flow control feature was added in ExtremeXOS 12.5.

The Forwarding Lookup-Key feaure show output is added in ExtremeXOS 15.3.

Platform Availability

This command is available only on BlackDiamond X8 series switches, BlackDiamond 8800 series switches, SummitStack, and Summit family switches.

Published August 2016prev | next

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