configure iparp distributed-mode

configure iparp distributed-mode [on | off]

Description

Configures the distributed IP ARP feature as either on or off.

Syntax Description

on	Configures the distributed IP ARP feature to become active after the next switch restart.
off	Configures the distributed IP ARP feature to become inactive after the next switch restart.

Default

Off.

Usage Guidelines

The distributed IP ARP feature provides higher IP ARP scaling by distributing IP ARP forwarding information to only the I/O module to which each IP host is connected. This feature is off by default to match the operation in ExtremeXOS releases prior to 12.5. When this feature is off, complete IP ARP information for all destinations is stored on all modules, reducing the available space for unique destinations.

If the sum of the values required for the configure iparp max_entries command for all VRs is greater than 8000, We recommend that you configure the distributed IP ARP feature as on, save the configuration, and activate the new configuration by restarting the switch.

Note

To activate or deactivate the distributed IP ARP feature, you must change the configuration, save the configuration, and restart the switch.

The distributed IP ARP feature imposes the following limitations:

The number of unique load share groups in a BlackDiamond 8800 series switch is reduced from 128 to 64 groups. On BlackDiamond X8, the number of load share groups is not reduced.
A load share group must include ports from only BlackDiamond 8000 c-, xl-, and xm-series modules or from modules that are not BlackDiamond 8000 c-, xl-, or xm-series modules. The switch does not support load share groups that mix ports from the two module groups when the distributed IP ARP is feature is active. On BlackDiamond X8, the limitation is not applicable; load share group ports may be from any module type.
Load distribution of IPv4 unicast packets across ports of a load share group is affected if the ingress port and any load share member ports reside on the same I/O module and port cluster within that module. Packets are distributed as expected if the ingress port is on a different module or different port cluster than all ports in the destination's load share group.
When the distributed IP ARP feature is active, access-lists with an action of either “redirect-port” or “redirect-port-list” will work only if the redirect port(s) have membership in the ingress VLAN when the IPv4 unicast packet‘s destination IP is locally attached to the switch (i.e. an ARP entry). If the ARP scale of a switch does not require distributed ARP to be active, the redirect-port / redirect-port-list access-list limitation can be avoided by leaving distributed ARP inactive.

To view the configured and current operational state of the distributed IP ARP feature, use the show iparp command.

To display distributed IP ARP statistics by slot when this feature is enabled, use the show iparp distributed-mode statistics command.

Example

The following example configures the distributed IP ARP feature to become active after the next switch restart:

configure iparp distributed-mode on

History

This command was first available in ExtremeXOS 12.5.

Platform Availability

This command is available on BlackDiamond X8 series switches, and BlackDiamond 8000 c-, xl-, and xm-series modules.

Published August 2016prev | next

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