igb Linux* Base Driver for Intel® Ethernet Network Connection
-------------------------------------------------------------


================================================================================

January 14, 2014

================================================================================

- Overview
- Identifying Your Adapter
- Building and Installation
- Command Line Parameters
- Additional Configurations
- Known Issues
- Support
- License

================================================================================


Overview
--------


The igb Linux base driver supports the 2.4.x, 2.6.x, and 3.x kernels. These
drivers includes support for Itanium® 2-based systems.

The igb driver supports 2.5 Gbps operating speed on 2500BASE-KX only for
I354-based network connections.

These drivers are only supported as a loadable module at this time. Intel is
not supplying patches against the kernel source to allow for static linking of
the drivers. For questions related to hardware requirements, refer to the
documentation supplied with your Intel Gigabit adapter. All hardware
requirements listed apply to use with Linux.

The following features are now available in supported kernels:

- Native VLANs
- Channel Bonding (teaming)
- SNMP

Channel Bonding documentation can be found in the Linux kernel source:
/documentation/networking/bonding.txt

The igb driver supports IEEE 1588 time stamping for kernels 2.6.30 and newer.

The driver information previously displayed in the /proc file system is not
supported in this release. Alternatively, you can use ethtool (version 1.6 or
later), lspci, and ifconfig to obtain the same information. Instructions on
updating ethtool can be found in the section Additional Configurations later
in this document.

================================================================================


Identifying Your Adapter
------------------------


For more information on how to identify your adapter, go to the Adapter &
Driver ID Guide at:
http://support.intel.com/support/go/network/adapter/idguide.htm

For the latest Intel network drivers for Linux, refer to the following
website. Select the link for your adapter.
http://support.intel.com/support/go/network/adapter/home.htm
================================================================================


Building and Installation
-------------------------


To build a binary RPM* package of this driver, run 'rpmbuild -tb igb.tar.gz'.

NOTES:

- For the build to work properly, the currently running kernel MUST match
  the version and configuration of the installed kernel sources. If you have
  just recompiled the kernel reboot the system before building.
- RPM functionality has only been tested in Red Hat distributions.

1. Move the base driver tar file to the directory of your choice. For
   example, use '/home/username/igb' or '/usr/local/src/igb'.

2. Untar/unzip the archive, where <x.x.x> is the version number for the
   driver tar file:
   tar zxf igb-<x.x.x>.tar.gz
3. Change to the driver src directory, where <x.x.x> is the version number
   for the driver tar:
   cd igb-<x.x.x>/src/
4. Compile the driver module:
   # make install

   The binary will be installed as:
   /lib/modules/<KERNEL VERSION>/kernel/drivers/net/igb/igb.[k]o

   The install location listed above is the default location. This may differ
   for various Linux distributions.

5. Load the module using the modprobe command:
   modprobe igb

   With 2.6 based kernels also make sure that older igb drivers are removed
   from the kernel, before loading the new module:
   rmmod igb; modprobe igb

6. Assign an IP address to the interface by entering the following, where x
   is the interface number:
   ifconfig eth <x> <IP_address>

7. Verify that the interface works. Enter the following, where IP_address
   is the IP address for another machine on the same subnet as the interface
   that is being tested:
   ping <IP_address>

TROUBLESHOOTING: Some systems have trouble supporting MSI and/or MSI-X
interrupts. If you believe your system needs to disable this style of
interrupt, the driver can be built and installed with the command:
# make CFLAGS_EXTRA=-DDISABLE_PCI_MSI install

Normally the driver will generate an interrupt every two seconds, so if you
can see that you are no longer getting interrupts in cat /proc/interrupts for
the ethX igb device, then this workaround may be necessary.


To build igb driver with DCA
----------------------------


If your kernel supports DCA, the driver will build by default with DCA enabled.

================================================================================


Command Line Parameters
-----------------------


If the driver is built as a module, the following optional parameters are used
by entering them on the command line with the modprobe command using this
syntax:
modprobe igb [<option>=<VAL1>,<VAL2>,...]

There needs to be a <VAL#> for each network port in the system supported by
this driver. The values will be applied to each instance, in function order.
For example:
modprobe igb InterruptThrottleRate=16000,16000

In this case, there are two network ports supported by igb in the system. The
default value for each parameter is generally the recommended setting, unless
otherwise noted.

NOTES:

- For more information about the AutoNeg, Duplex, and Speed parameters, see
  the Speed and Duplex Configuration section.
- For more information about the InterruptThrottleRate, RxIntDelay,
  TxIntDelay, RxAbsIntDelay, and TxAbsIntDelay parameters, see the application
  note at: http://www.intel.com/design/network/applnots/ap450.htm
- A descriptor describes a data buffer and attributes related to the data
  buffer. This information is accessed by the hardware.


InterruptThrottleRate
---------------------


Valid Range:  0,1,3, 100-100000 (0=off, 1=dynamic, 3=dynamic conservative)

Default Value:  3

The driver can limit the amount of interrupts per second that the adapter will
generate for incoming packets. It does this by writing a value to the adapter
that is based on the maximum amount of interrupts that the adapter will
generate per second.

Setting InterruptThrottleRate to a value greater or equal to 100 will program
the adapter to send out a maximum of that many interrupts per second, even if
more packets have come in. This reduces interrupt load on the system and can
lower CPU utilization under heavy load, but will increase latency as packets
are not processed as quickly.

The default behavior of the driver previously assumed a static
InterruptThrottleRate value of 8000, providing a good fallback value for all
traffic types, but lacking in small packet performance and latency. However,
the hardware can handle many more small packets per second. For this reason,
an adaptive interrupt moderation algorithm was implemented.

The driver has two adaptive modes (setting 1 or 3) in which it dynamically
adjusts the InterruptThrottleRate value based on the traffic that it receives.
After determining the type of incoming traffic in the last timeframe, it will
adjust the InterruptThrottleRate to an appropriate value for that traffic.

The algorithm classifies the incoming traffic every interval into classes.
Once the class is determined, the InterruptThrottleRate value is adjusted to
suit that traffic type the best. There are three classes defined:

- "Bulk traffic", for large amounts of packets of normal size
- "Low latency", for small amounts of traffic and/or a significant
  percentage of small packets
- "Lowest latency", for almost completely small packets or minimal traffic

In dynamic conservative mode, the InterruptThrottleRate value is set to 4000
for traffic that falls in class "Bulk traffic". If traffic falls in the "Low
latency" or "Lowest latency" class, the InterruptThrottleRate is increased
stepwise to 20000. This default mode is suitable for most applications.

For situations where low latency is vital, such as cluster or grid computing,
the algorithm can reduce latency even more when InterruptThrottleRate is set
to mode 1. In this mode, which operates the same as mode 3, the
InterruptThrottleRate will be increased stepwise to 70000 for traffic in class
"Lowest latency".

Setting InterruptThrottleRate to 0 turns off any interrupt moderation and may
improve small packet latency, but is generally not suitable for bulk
throughput traffic.

NOTES:

- Dynamic interrupt throttling is only applicable to adapters operating in
  MSI or Legacy interrupt mode, using a single receive queue.
- InterruptThrottleRate takes precedence over the TxAbsIntDelay and
  RxAbsIntDelay parameters. In other words, minimizing the receive and/or
  transmit absolute delays does not force the controller to generate more
  interrupts than what the Interrupt Throttle Rate allows.
- When igb is loaded with default settings and multiple adapters are in use
  simultaneously, the CPU utilization may increase non-linearly. In order to
  limit the CPU utilization without impacting the overall throughput, we
  recommend that you load the driver as follows: modprobe igb
  InterruptThrottleRate=3000,3000,3000 This sets the InterruptThrottleRate to
  3000 interrupts/sec for the first, second, and third instances of the
  driver. The range of 2000 to 3000 interrupts per second works on a majority
  of systems and is a good starting point, but the optimal value will be
  platform-specific. If CPU utilization is not a concern, use default driver
  settings.


LLI (Low Latency Interrupts)
----------------------------


LLI allows for immediate generation of an interrupt upon processing receive
packets that match certain criteria as set by the parameters described below.
LLI parameters are not enabled when Legacy interrupts are used. You must be
using MSI or MSI-X (see cat /proc/interrupts) to successfully use LLI.


LLIPort
-------


Valid Range:    0-65535

Default Value:  0 (disabled)

LLI is configured with the LLIPort command-line parameter, which specifies
which TCP port should generate Low Latency Interrupts.

For example, using LLIPort=80 would cause the board to generate an immediate
interrupt upon receipt of any packet sent to TCP port 80 on the local machine.

WARNING: Enabling LLI can result in an excessive number of interrupts/second
that may cause problems with the system and in some cases may cause a kernel
panic.


LLIPush
-------


Valid Range:    0-1

Default Value:  0 (disabled)

LLIPush can be set to be enabled or disabled (default). It is most effective
in an environment with many small transactions.

NOTE: Enabling LLIPush may allow a denial of service attack.


LLISize
-------


Valid Range:    0-1500

Default Value:  0 (disabled)

LLISize causes an immediate interrupt if the board receives a packet smaller
than the specified size.


IntMode
-------


Valid Range:    0-2 (0 = Legacy Int, 1 = MSI and 2 = MSI-X)

Default Value:  2

IntMode controls allow load time control over the type of interrupt registered
for by the driver. MSI-X is required for multiple queue support, and some
kernels and combinations of kernel .config options will force a lower level of
interrupt support. 'cat /proc/interrupts' will show different values for each
type of interrupt.


RSS
---


Valid Range:    0-8

Default Value:  1

0 = Assign up to the lesser value of the number of CPUs or the number of queues

X = Assign X queues, where X is less than or equal to the maximum number of
queues. The driver allows maximum supported queue value. For example,
I350-based adapters allow RSS=8, where 8 queues is the maximum allowable
queues.

NOTE: For 82575-based adapters, the maximum number of queues is 4; for
82576-based and newer adapters it is 8; for I210-based adapters it is 4
queues; and for I211-based adapters it is 2 queues.

This parameter is also affected by the VMDq parameter in that it will limit
the queues more.
      VMDQ
Model 0 1 2 3+
82575 4 4 3 1
82576 8 2 2 2
82580 8 1 1 1

VMDQ
----


Valid Range:    0-4 on 82575-based adapters; 0-8 for 82576/82580-based adapters

Default Value:  0

Supports enabling VMDq pools as this is needed to support SR-IOV.

0 = Disabled

1 = Sets the netdev as pool 0

2+ = Add additional queues but they currently are not used

This parameter is forced to 1 or more if the max_vfs module parameter is used.
In addition, the number of queues available for RSS is limited if this is set
to 1 or greater.

NOTE: When either SR-IOV mode or VMDq mode is enabled, hardware VLAN filtering
and VLAN tag stripping/insertion will remain enabled.


max_vfs
-------


Valid Range:    0-7

Default Value:  0

If the value is greater than 0 it will also force the VMDq parameter to be 1
or more.

This parameter adds support for SR-IOV. It causes the driver to spawn up to
max_vfs worth of virtual function.

NOTE: When either SR-IOV mode or VMDq mode is enabled, hardware VLAN filtering
and VLAN tag stripping/insertion will remain enabled. Please remove the old
VLAN filter before the new VLAN filter is added. For example,
ip link set eth0 vf 0 vlan 100     // set vlan 100 for VF 0
ip link set eth0 vf 0 vlan 0       // Delete vlan 100
ip link set eth0 vf 0 vlan 200     // set a new vlan 200 for VF 0

QueuePairs
----------


Valid Range:    0-1

Default Value:  1 (Tx and Rx will be paired onto one interrupt vector)

If set to 0, when MSI-X is enabled, the Tx and Rx will attempt to occupy
separate vectors.

This option can be overridden to 1 if there are not sufficient interrupts
available. This can occur if any combination of RSS, VMDQ, and max_vfs results
in more than 4 queues being used.


Node
----


Valid Range:    0-n
n is the number of the NUMA node that should be used to allocate memory for
this adapter port.

Default Value:  -1 (off)
A value of -1 uses the driver default of allocating memory on whichever
processor is running modprobe.

The Node parameter will allow you to pick which NUMA node you want to have the
adapter allocate memory from. All driver structures, in-memory queues, and
receive buffers will be allocated on the node specified. This parameter is
only useful when interrupt affinity is specified. Otherwise, some portion of
the time, the interrupt could run on a different core than the memory is
allocated on, causing slower memory access and impacting throughput, CPU, or
both.


EEE (Energy Efficient Ethernet)
-------------------------------


Valid Range:    0-1

Default Value:  1 (enabled)

A link between two EEE-compliant devices will result in periodic bursts of
data followed by periods where the link is in an idle state. This Low Power
Idle (LPI) state is supported in both 1 Gbps and 100 Mbps link speeds.

NOTE: EEE support requires auto-negotiation.


DMAC
----


Valid Range:    0, 250, 500, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000,
9000, 10000

Default Value:  0 (disabled)

This parameter nables or disables DMA Coalescing feature. Values are in
microseconds and increase the internal DMA Coalescing internal timer. DMA
(Direct Memory Access) allows the network device to move packet data directly
to the system's memory, reducing CPU utilization. However, the frequency and
random intervals at which packets arrive do not allow the system to enter a
lower power state. DMA Coalescing allows the adapter to collect packets before
it initiates a DMA event. This may increase network latency but also increases
the chances that the system will enter a lower power state.

Turning on DMA Coalescing may save energy with kernel 2.6.32 and newer. This
will impart the greatest chance for your system to consume less power. DMA
Coalescing is effective in helping potentially saving the platform power only
when it is enabled across all active ports.

InterruptThrottleRate (ITR) should be set to dynamic. When ITR=0, DMA
Coalescing is automatically disabled.

A whitepaper containing information on how to best configure your platform is
available on the Intel website.


MDD (Malicious Driver Detection)
--------------------------------


Valid Range:    0-1

Default Value:  1 (enabled)

0 = Disabled

1 = Enabled

This parameter is only relevant for I350 devices operating in SR-IOV mode.
When this parameter is set, the driver detects malicious VF driver and
disables its Tx/Rx queues until a VF driver reset occurs.

================================================================================


Additional Configurations
-------------------------



Configuring the Driver on Different Distributions
-------------------------------------------------


Configuring a network driver to load properly when the system is started is
distribution dependent. Typically, the configuration process involves adding
an alias line to /etc/modules.conf or /etc/modprobe.conf as well as editing
other system startup scripts and/or configuration files. Many popular Linux
distributions ship with tools to make these changes for you. To learn the
proper way to configure a network device for your system, refer to your
distribution documentation. If during this process you are asked for the
driver or module name, the name for the Linux Base Driver for the Gigabit
family of adapters is igb.

As an example, if you install the igb driver for two Gigabit adapters (eth0
and eth1) and want to set the interrupt mode to MSI-X and MSI respectively,
add the following to modules.conf or /etc/modprobe.conf:

     alias eth0 igb
     alias eth1 igb
     options igb IntMode=2,1


Viewing Link Messages
---------------------


Link messages will not be displayed to the console if the distribution is
restricting system messages. In order to see network 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 Maximum Transmission Unit
(MTU) to a value larger than the default value of 1500. Use the ifconfig
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>. This example applies
to the Red Hat distributions. Other distributions may store this setting in a
different location.

NOTES:

- To enable Jumbo Frames, increase the MTU size on the interface beyond 1500.
- The maximum MTU setting for Jumbo Frames is 9216. This value coincides
  with the maximum Jumbo Frames size of 9234 bytes.
- Using Jumbo frames at 10 or 100 Mbps is not supported and may result in
  poor performance or loss of link.


ethtool
-------


The driver utilizes the ethtool interface for driver configuration and
diagnostics, as well as displaying statistical information. ethtool version 3
or later is required for this functionality, although we strongly recommend
downloading the latest version at:

http://ftp.kernel.org/pub/software/network/ethtool/.


Speed and Duplex Configuration
------------------------------


In addressing speed and duplex configuration issues, you need to distinguish
between copper-based adapters and fiber-based adapters.

In the default mode, an Intel® Network Adapter using copper connections will
attempt to auto-negotiate with its link partner 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.

Speed and Duplex are configured through the ethtool* utility. ethtool is
included with all versions of Red Hat after Red Hat 7.2. For other Linux
distributions, download and install ethtool from the following website:
http://ftp.kernel.org/pub/software/network/ethtool/.

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.

An Intel® Network Adapter using fiber-based connections, however, will not
attempt to auto-negotiate with its link partner since those adapters operate
only in full duplex and only at their native speed.


Enabling Wake on LAN* (WoL)
---------------------------


WoL is configured through the ethtool* utility. ethtool is included with all
versions of Red Hat after Red Hat 7.2. For other Linux distributions, download
and install ethtool from the following website:
http://ftp.kernel.org/pub/software/network/ethtool/.

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 driver must be loaded prior
to shutting down or suspending the system.

NOTES :

- Wake On LAN is only supported on port A of multi-port devices.
- Wake On LAN is not supported for the Intel® Gigabit VT Quad Port Server
  Adapter.


Multiqueue
----------


In this mode, a separate MSI-X vector is allocated for each queue and one for
"other" interrupts such as link status change and errors. All interrupts are
throttled via interrupt moderation. Interrupt moderation must be used to avoid
interrupt storms while the driver is processing one interrupt. The moderation
value should be at least as large as the expected time for the driver to
process an interrupt. Multiqueue is off by default.

REQUIREMENTS: MSI-X support is required for Multiqueue. If MSI-X is not found,
the system will fallback to MSI or to Legacy interrupts. This driver supports
multiqueue in kernel versions 2.6.24 and newer. This driver supports receive
multiqueue on all kernels that support MSI-X.

NOTES:

- Do not use MSI-X with the 2.6.19 or 2.6.20 kernels.
- On some kernels a reboot is required to switch between single queue mode
  and multiqueue mode or vice-versa.


LRO
---


Large Receive Offload (LRO) is a technique for increasing inbound throughput
of high-bandwidth network connections by reducing CPU overhead. It works by
aggregating multiple incoming packets from a single stream into a larger
buffer before they are passed higher up the networking stack, thus reducing
the number of packets that have to be processed. LRO combines multiple
Ethernet frames into a single receive in the stack, thereby potentially
decreasing CPU utilization for receives.

NOTE: LRO requires 2.4.22 or later kernel version.

IGB_LRO is a compile time flag. The user can enable it at compile time to add
support for LRO from the driver. The flag is used by adding
CFLAGS_EXTRA="-DIGB_LRO" to the make file when it's being compiled.
# make CFLAGS_EXTRA="-DIGB_LRO" install

You can verify that the driver is using LRO by looking at these counters in
ethtool:

- lro_aggregated - counts total packets that were combined
- lro_flushed - counts the number of packets flushed out of LRO
- lro_recycled - counts the number of buffers returned to the ring from
  recycling

NOTE: IPv6 and UDP are not supported by LRO.


IEEE 1588 Precision Time Protocol (PTP) Hardware Clock (PHC)
------------------------------------------------------------


Precision Time Protocol (PTP) is an implementation of the IEEE 1588
specification allowing network cards to synchronize their clocks over a
PTP-enabled network. It works through a series of synchronization and delay
notification transactions that allow a software daemon to implement a PID
controller to synchronize the network card clocks.

NOTE: PTP requires 3.0.0 or later kernel version that has PTP support enabled
in the kernel and a user-space software daemon.

IGB_PTP is a compile time flag. The user can enable it at compile time to add
support for PTP from the driver. The flag is used by adding
CFLAGS_EXTRA="-DIGB_PTP" to the make file when it is being compiled:
make CFLAGS_EXTRA="-DIGB_PTP" install

NOTE: The driver will fail to compile if your kernel does not support PTP.

You can verify that the driver is using PTP by looking at the system log to
see whether a PHC was attempted to be registered or not. If you have a kernel
and version of ethtool with PTP support, you can check the PTP support in the
driver by executing:
ethtool -T ethX

MAC and VLAN anti-spoofing feature
----------------------------------


When a malicious driver attempts to send a spoofed packet, it is dropped by
the hardware and not transmitted. An interrupt is sent to the PF driver
notifying it of the spoof attempt. When a spoofed packet is detected, the PF
driver will send the following message to the system log (displayed by the
"dmesg" command):
Spoof event(s) detected on VF(n), where n = the VF that attempted to do the
spoofing

Setting MAC Address, VLAN and Rate Limit Using IProute2 Tool
------------------------------------------------------------


You can set a MAC address of a Virtual Function (VF), a default VLAN and the
rate limit using the IProute2 tool. Download the latest version of the
IProute2 tool from Sourceforge if your version does not have all the features
you require.

================================================================================


Known Issues/Troubleshooting
----------------------------



Hardware Issues
---------------


For known hardware and troubleshooting issues, either refer to the "Release
Notes" in your User Guide, or for more detailed information, go to
http://www.intel.com.

In the search box enter your devices controller ID followed by "spec update"
(i.e., 82599 spec update). The specification update file has complete
information on known hardware issues.


Software Issues
---------------


NOTE: After installing the driver, if your Intel Ethernet Network Connection
is not working, verify that you have installed the correct driver.


Using the igb driver on 2.4 or older 2.6 based kernels
------------------------------------------------------


Due to limited support for PCI-Express in 2.4 kernels and older 2.6 kernels,
the igb driver may run into interrupt related problems on some systems, such
as no link or hang when bringing up the device.

We recommend the newer 2.6 based kernels, as these kernels correctly configure
the PCI-Express configuration space of the adapter and all intervening
bridges. If you are required to use a 2.4 kernel, use a 2.4 kernel newer than
2.4.30. For 2.6 kernels we recommend using the 2.6.21 kernel or newer.

Alternatively, on 2.6 kernels you may disable MSI support in the kernel by
booting with the "pci=nomsi" option or permanently disable MSI support in your
kernel by configuring your kernel with CONFIG_PCI_MSI unset.


Intel® Active Management Technology 2.0, 2.1, 2.5 not supported in conjunction
with Linux driver



Detected Tx Unit Hang in Quad Port Adapters
-------------------------------------------


In some cases ports 3 and 4 don't pass traffic and report 'Detected Tx Unit
Hang' followed by 'NETDEV WATCHDOG: ethX: transmit timed out' errors. Ports 1
and 2 do not show any errors and will pass traffic.

This issue may be resolved by updating to the latest kernel and BIOS. The user
is encouraged to run an OS that fully supports MSI interrupts. You can check
your system BIOS by downloading the Linux Firmware Developer Kit at
http://www.linuxfirmwarekit.org/.


Driver Compilation
------------------


When trying to compile the driver by running make install, the following error
may occur:  "Linux kernel source not configured - missing version.h"

To solve this issue, create the version.h file by going to the Linux source
tree and entering:
# make include/linux/version.h

Performance Degradation with Jumbo Frames
-----------------------------------------


Degradation in throughput performance may be observed in some Jumbo frames
environments. If this is observed, increasing the application's socket buffer
size and/or increasing the /proc/sys/net/ipv4/tcp_*mem entry values may help.
See the specific application manual and
/usr/src/linux*/Documentation/networking/ip-sysctl.txt for more details.


Jumbo frames on Foundry BigIron 8000 switch
-------------------------------------------


There is a known issue using Jumbo frames when connected to a Foundry BigIron
8000 switch. This is a 3rd party limitation. If you experience loss of
packets, lower the MTU size.


Multiple Interfaces on Same Ethernet Broadcast Network
------------------------------------------------------


Due to the default ARP behavior on Linux, it is not possible to have one
system on two IP networks in the same Ethernet broadcast domain
(non-partitioned switch) behave as expected. All Ethernet interfaces will
respond to IP traffic for any IP address assigned to the system. This results
in unbalanced receive traffic.

If you have multiple interfaces in a server, either turn on ARP filtering by
entering: echo 1 > /proc/sys/net/ipv4/conf/all/arp_filter

This only works if your kernel's version is higher than 2.4.5.

NOTE: This setting is not saved across reboots. The configuration change can
be made permanent by adding the following line to the /etc/sysctl.conf file:
net.ipv4.conf.all.arp_filter = 1

or,
install the interfaces in separate broadcast domains (either in different
switches or in a switch partitioned to VLANs)

Disable Rx Flow Control with ethtool
------------------------------------


In order to disable receive flow control using ethtool, you must turn off
auto-negotiation on the same command line.

For example:
ethtool -A eth? autoneg off rx off

Unplugging Network Cable While ethtool -p is Running
----------------------------------------------------


In kernel versions 2.5.50 and newer, unplugging the network cable while 
ethtool -p is running will cause the system to become unresponsive to 
keyboard commands, except for control-alt-delete. Restarting the system 
appears to be the only remedy.


Trouble Passing Traffic on Ports 1 and 2 Using RHEL3
----------------------------------------------------


There is a known hardware compatibility issue on some systems with RHEL3
kernels. Traffic on ports 1 and 2 may be slower than expected, and ping times,
higher than expected.

This issue MAY be resolved by updating to the latest kernel and BIOS. You can
check your system BIOS by downloading the Linux Firmware Developer Kit at
http://www.linuxfirmwarekit.org/.


Do Not Use LRO When Routing Packets
-----------------------------------

Due to a known general compatibilty issue with LRO and routing, do not use LRO
when routing packets.


Build Error with Asianux 3.0 - Redefinition of typedef 'irq_handler_t'
----------------------------------------------------------------------

Some systems may experience build issues due to the redefinition of
irq_handler_t. To resolve this issue, build the driver (step 4 above) using
the command:
# make CFLAGS_EXTRA=-DAX_RELEASE_CODE=1 install

MSI-X Issues with Kernels between 2.6.19 and 2.6.21 (inclusive)
---------------------------------------------------------------

Kernel panics and instability may be observed on any MSI-X hardware if you use
irqbalance with kernels between 2.6.19 and 2.6.21. If such problems are
encountered, you may disable the irqbalance daemon or upgrade to a newer
kernel.

Rx Page Allocation Errors
-------------------------

"order:0" errors may occur under stress with kernels 2.6.25 and newer. This is
caused by the way the Linux kernel reports this stressed condition.


Under Redhat 5.4-GA, System May Crash when Closing Guest OS Window after
Loading/Unloading Physical Function (PF) Driver


Do not remove the igb driver from Dom0 while Virtual Functions (VFs) are
assigned to guests. VFs must first use the xm "pci-detach" command to hot-plug
the VF device out of the VM it is assigned to or else shut down the VM.


SLES10 SP3 Random System Panic when Reloading Driver
----------------------------------------------------


This is a known SLES-10 SP3 issue. After requesting interrupts for MSI-X
vectors, system may panic.

Currently, the only known workaround is to build the driver with
CFLAGS_EXTRA=-DDISABLE_PCI_MSI if the driver needs to be loaded/unloaded.
Otherwise, the driver can be loaded once and will be safe, but unloading it
will lead to the issue.


Enabling SR-IOV in a 32-bit Microsoft* Windows* Server 2008 Guest OS Using
Intel® 82576-based GbE or Intel® 82599-based 10GbE Controller Under KVM


KVM Hypervisor/VMM supports direct assignment of a PCIe device to a VM. This
includes traditional PCIe devices, as well as SR-IOV-capable devices using
Intel 82576-based and 82599-based controllers.

While direct assignment of a PCIe device or an SR-IOV Virtual Function (VF) to
a Linux-based VM running 2.6.32 or newer kernel is functional, there is a
known issue with Microsoft Windows Server 2008 VM that results in a "yellow
bang" error. This problem is within the KVM VMM itself, not the Intel driver
or the SR-IOV logic of the VMM. The KVM emulates an older CPU model for the
guests, and this older CPU model does not support MSI-X interrupts, which is a
requirement for Intel SR-IOV.

If you wish to use the Intel 82576- or 82599-based controllers in SR-IOV mode
with KVM and a Microsoft Windows Server 2008 guest, try the following
workaround. The workaround is to tell KVM to emulate a different model of CPU
when using qemu to create the KVM guest:
"-cpu qemu64,model=13"

Host May Reboot after Removing PF when VF is Active in Guest
------------------------------------------------------------


Using kernel versions earlier than 3.2, do not unload the PF driver with
active VFs. Doing this will cause your VFs to stop working until you reload
the PF driver and may cause a spontaneous reboot of your system.

================================================================================


Support
-------


For general information, go to the Intel support website at:
www.intel.com/support/

or the Intel Wired Networking project hosted by Sourceforge at:
http://sourceforge.net/projects/e1000

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 e1000-devel@lists.sf.net.

================================================================================


License
-------


Intel Gigabit Linux driver.
Copyright(c) 1999 - 2013 Intel Corporation.

This program is free software; you can redistribute it and/or modify it under
the terms and conditions of the GNU General Public License, version 2, as
published by the Free Software Foundation.

This program is distributed in the hope it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 51 Franklin
St - Fifth Floor, Boston, MA 02110-1301 USA.

The full GNU General Public License is included in this distribution in the
file called "COPYING".

================================================================================


Trademarks
----------


Intel, Itanium, and Pentium are trademarks or registered trademarks of Intel
Corporation or its subsidiaries in the United States and other countries.

* Other names and brands may be claimed as the property of others.