Viewing link messages, Jumbo frames, Ethtool – Dell Intel PRO Family of Adapters User Manual
Page 79: Speed and duplex configuration, Enabling wake on lan
Viewing Link Messages
Link messages will not be displayed to the console if the distribution is restricting system messages. In order to see net-
work driver link messages on your console, set dmesg to eight by entering the following:
dmesg -n 8
NOTE: This setting is not saved across reboots.
Jumbo Frames
Jumbo Frames support is enabled by changing the MTU to a value larger than the default of 1500 bytes. Use the ifcon-
fig command to increase the MTU size. For example:
ifconfig eth<x> mtu 9000 up
This setting is not saved across reboots. The setting change can be made permanent by adding MTU = 9000 to the file
/etc/sysconfig/network-scripts/ifcfg-eth<x>
, in Red Hat distributions. Other distributions may store this set-
ting in a different location.
NOTES:
l
Using Jumbo Frames at 10 or 100 Mbps may result in poor performance or loss of link.
l
To enable Jumbo Frames, increase the MTU size on the interface beyond 1500.
l
The maximum Jumbo Frames size is 9234 bytes, with a corresponding MTU size of
9216 bytes.
ethtool
The driver utilizes the ethtool interface for driver configuration and diagnostics, as well as displaying statistical inform-
ation. ethtool version 3 or later is required for this functionality, although we strongly recommend downloading the
latest version at:
Speed and Duplex Configuration
In the default mode, an Intel® Network Adapter using copper connections will attempt to auto-negotiate with its link part-
ner to determine the best setting. If the adapter cannot establish link with the link partner using auto-negotiation, you
may need to manually configure the adapter and link partner to identical settings to establish link and pass packets.
This should only be needed when attempting to link with an older switch that does not support auto-negotiation or one
that has been forced to a specific speed or duplex mode.
Your link partner must match the setting you choose. Fiber-based adapters operate only in full duplex, and only at their
native speed.
Speed and Duplex are configured through the ethtool* utility. ethtool is included with all versions of Red Hat after Red
CAUTION: Only experienced network administrators should force speed and duplex manually. The settings at
the switch must always match the adapter settings. Adapter performance may suffer or your adapter may not
operate if you configure the adapter differently from your switch.
Enabling Wake on LAN*
Wake on LAN (WOL) is configured through the ethtool* utility. ethtool is included with all versions of Red Hat after Red
For instructions on enabling WOL with ethtool, refer to the website listed above.
WOL will be enabled on the system during the next shut down or reboot. For this driver version, in order to enable
WOL, the igb driver must be loaded prior to shutting down or suspending the system.
NOTE: Wake on LAN is only supported on port A of multi-port devices.