Oracle Solaris Tunable Parameters Reference Manual

ip_multidata_outbound (Solaris 9 Release)

This parameter information changed significantly in releases after the Solaris 9 8/03 release. Please see ip_multidata_outbound for more information.


This parameter enables the network stack to send more than one packet at one time to the network device driver during transmission.

Enabling this parameter reduces the per-packet processing costs by improving the host CPU utilization and/or network throughput.

The multidata transmit (MDT) feature is only effective for device drivers that support this feature.

The following parameter must be enabled in the /etc/system file to use the MDT parameter:

set ip:ip_use_dl_cap = 0x1




0 (disabled), 1 (enabled)



When to Change

This feature can be enabled at any time to allow for improved system performance with the following cautions:

  • Enabling this feature might change the appearance of any packets between the IP layer and the DLPI provider. So, any third-party STREAMS module that is dynamically inserted between the IP layer and the DLPI provider by using ifconfig's modinsert feature, which doesn't understand the MDT STREAMS data type, might not work.

    Modules that are inserted between the IP and the DLPI provider with the autopush(1m) mechanism might not work as well.

  • Keep this feature disabled when a STREAMS module is not MDT aware. For example, the public domain utilities such as ipfilter, Checkpoint Firewall-1, and so on, are not MDT aware.

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