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if_em(4)

NAME

     em -- Intel(R) PRO/1000 Gigabit Ethernet adapter driver

SYNOPSIS

     device em

DESCRIPTION

     The em driver provides support for PCI Gigabit Ethernet adapters based on
     the Intel 82540, 82541ER, 82541PI, 82542, 82543, 82544, 82545, 82546,
     82546EB, 82546GB and 82547 Ethernet controller chips.  The driver sup-
     ports Transmit/Receive checksum offload and Jumbo Frames only on 82540,
     82543, 82544 and 82546-based adapters.  For further hardware information,
     see the README included with the driver.

     For questions related to hardware requirements, refer to the documenta-
     tion supplied with your Intel PRO/1000 adapter.  All hardware require-
     ments listed apply to use with FreeBSD.

     Support for Jumbo Frames is provided via the interface MTU setting.
     Selecting an MTU larger than 1500 bytes with the ifconfig(8) utility con-
     figures the adapter to receive and transmit Jumbo Frames.	The maximum
     MTU size for Jumbo Frames is 16114.

     This driver version supports VLANs.  For information on enabling VLANs,
     see the README.  The em driver supports the following media types:

     autoselect   Enables auto-negotiation for speed and duplex.

     10baseT/UTP  Sets 10Mbps operation.  Use the mediaopt option to select
		  full-duplex mode.

     100baseTX	  Sets 100Mbps operation.  Use the mediaopt option to select
		  full-duplex mode.

     1000baseSX   Sets 1000Mbps operation.  Only full-duplex mode is supported
		  at this speed.

     1000baseTX   Sets 1000Mbps operation.  Only full-duplex mode is supported
		  at this speed.

     The em driver supports the following media options:

     full-duplex  Forces full-duplex operation

     half-duplex  Forces half-duplex operation.

     Only use mediaopt to set the driver to full-duplex.  If mediaopt is not
     specified, the driver defaults to half-duplex.

     For more information on configuring this device, see ifconfig(8).

HARDWARE

     The em driver supports Gigabit Ethernet adapters based on the Intel
     82540, 82541ER, 82541PI, 82542, 82543, 82544, 82545, 82546, 82546EB,
     82546GB and 82547 controller chips:

     o	 Intel PRO/1000 CT Network Connection (82547)
     o	 Intel PRO/1000 MT Dual Port Server Adapter (82546)
     o	 Intel PRO/1000 MT Quad Port Server Adapter (82546EB)
     o	 Intel PRO/1000 MT Server Adapter (82545)
     o	 Intel PRO/1000 T Desktop Adapter (82544)
     o	 Intel PRO/1000 T Server Adapter (82543)
     o	 Intel PRO/1000 XF Server Adapter (82544)
     o	 Intel PRO/1000 XT Server Adapter (82544)

DIAGNOSTICS

     em%d: Unable to allocate bus resource: memory  A fatal initialization
     error has occurred.

     em%d: Unable to allocate bus resource: interrupt  A fatal initialization
     error has occurred.

     em%d: watchdog timeout -- resetting  The device has stopped responding to
     the network, or there is a problem with the network connection (cable).

SUPPORT

     For additional information regarding building and installation, see the
     README included with the driver.  For general information and support, go
     to the Intel support website at: http://support.intel.com.

     If an issue is identified with the released source code on the supported
     kernel with a supported adapter, email the specific information related
     to the issue to <freebsdnic@mailbox.intel.com>.

SEE ALSO

     arp(4), gx(4), netintro(4), ng_ether(4), polling(4), vlan(4), ifconfig(8)

HISTORY

     The em device driver first appeared in FreeBSD 4.4.

AUTHORS

     The em driver was written by Intel Corporation
     <freebsdnic@mailbox.intel.com>.

BUGS

     Hardware-assisted VLAN processing is disabled by default.	You can enable
     it on an em interface using ifconfig(8) unless you are going to run
     bridge(4) on the interface.  In any case, VLAN can operate safely without
     the hardware acceleration.

FreeBSD 5.4		       January 30, 2005 		   FreeBSD 5.4

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