igb Linux* Base Driver for Intel(R) Ethernet Network Connection
***************************************************************

July 15, 2024


Contents
^^^^^^^^

* igb Linux* Base Driver for Intel(R) Ethernet Network Connection

  * Important Notes

  * Overview

  * Related Documentation

  * Identifying Your Adapter

  * Building and Installation

  * Command Line Parameters

  * Additional Features and Configurations

  * Known Issues/Troubleshooting

  * Support

  * License

  * Trademarks


Important Notes
===============


Configuring SR-IOV for improved network security
------------------------------------------------

In a virtualized environment, on Intel(R) Ethernet Network Adapters
that support SR-IOV, the virtual function (VF) may be subject to
malicious behavior. Software-generated layer-two frames, like IEEE
802.3x (link flow control), IEEE 802.1Qbb (priority based flow-
control), and others of this type, are not expected and can throttle
traffic between the host and the virtual switch, reducing performance.

To resolve this issue, and to ensure isolation from unintended traffic
streams, configure all SR-IOV enabled ports for VLAN tagging from the
administrative interface on the PF. This configuration allows
unexpected, and potentially malicious, frames to be dropped.


Overview
========

This driver supports kernel versions 2.6.30 or newer. However, some
features may require a newer kernel version. The associated Virtual
Function (VF) driver for this driver is igbvf.

Driver information can be obtained using ethtool, lspci, and ip.

This driver is 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 adapter. All hardware
requirements listed apply to use with Linux.

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


Related Documentation
=====================

See the "Intel(R) Ethernet Adapters and Devices User Guide" for
additional information on features:

* https://cdrdv2.intel.com/v1/dl/getContent/705831

* https://www.intel.com/content/www/us/en/download/19373/adapter-user-
  guide-for-intel-ethernet-adapters.html


Identifying Your Adapter
========================

For information on how to identify your adapter, and for the latest
Intel network drivers, refer to the Intel Support website:
http://www.intel.com/support.


Building and Installation
=========================


How to Manually Build the Driver
--------------------------------

1. Move the virtual function 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 VER>/updates/drivers/net/ethernet/intel/igb/igb.ko

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

5. Load the module using the modprobe command.

   To check the version of the driver and then load it:

      modinfo igb
      modprobe igb

   Alternately, make sure that any 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 "<ethX>" is the interface name that was shown in dmesg after
   modprobe:

      ip address add <IP_address>/<netmask bits> dev <ethX>

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>

Note:

  For certain distributions like (but not limited to) Red Hat
  Enterprise Linux 7 and Ubuntu, once the driver is installed, you may
  need to update the initrd/initramfs file to prevent the OS loading
  old versions of the igb driver.For Red Hat distributions:

     dracut --force

  For Ubuntu:

     update-initramfs -u


How to Build a Binary RPM Package of This Driver
------------------------------------------------

Note:

  RPM functionality has only been tested in Red Hat distributions.

1. Run the following command, where "<x.x.x>" is the version number
   for the driver tar file:

      rpmbuild -tb igb-<x.x.x>.tar.gz

   Note:

     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.

2. After building the RPM, the last few lines of the tool output
   contain the location of the RPM file that was built. Install the
   RPM with one of the following commands, where "<RPM>" is the
   location of the RPM file:

      rpm -Uvh <RPM>

   or:

      dnf/yum localinstall <RPM>

Note:

  * To compile the driver on some kernel/arch combinations, you may
    need to install a package with the development version of libelf
    (e.g. libelf-dev, libelf-devel, elfutils-libelf-devel).

  * When compiling an out-of-tree driver, details will vary by
    distribution. However, you will usually need a kernel-devel RPM or
    some RPM that provides the kernel headers at a minimum. The RPM
    kernel-devel will usually fill in the link at "/lib/modules/'uname
    -r'/build".


Building the igb Driver with DCA
--------------------------------

If your kernel supports Direct Cache Access (DCA), the driver will
build by default with DCA enabled.


Command Line Parameters
=======================

If the driver is built as a module, enter optional parameters on the
command line with the following 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.


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

Valid Range:

* 0 = off

* 1 = dynamic

* 3 = dynamic conservative

* "<min_ITR>-<max_ITR>"

Interrupt Throttle Rate (ITR) controls the number of interrupts each
interrupt vector can generate per second. Increasing ITR lowers
latency at the cost of increased CPU utilization, though it may help
throughput in some circumstances.

* 0 = Setting "InterruptThrottleRate" to 0 turns off any interrupt
  moderation and may improve small packet latency. However, this is
  generally not suitable for bulk throughput traffic due to the
  increased CPU utilization of the higher interrupt rate.

* 1 = Setting "InterruptThrottleRate" to Dynamic mode attempts to
  moderate interrupts per vector while maintaining very low latency.
  This can sometimes cause extra CPU utilization. If planning on
  deploying igb in a latency sensitive environment, this parameter
  should be considered.

* "<min_ITR>-<max_ITR>" = 100-100000

  Setting "InterruptThrottleRate" to a value greater or equal to
  "<min_ITR>" will program the adapter to send at most 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.

Note:

  "InterruptThrottleRate" is NOT supported by 82542, 82543, or
  82544-based adapters.


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

Low Latency Interrupts (LLI) allow 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

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

"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

"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

* 2 = MSI-X

"IntMode" controls the allowed 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

* 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 (8 queues)

The maximum number of queues allowed are:

* I350-based adapters: 8 queues

* 82575-based adapters: 4 queues

* 82576-based and newer adapters: 8 queues

* I210-based adapters: 4 queues

* I211-based adapters: 2 queues

This parameter is also affected by the "VMDq" parameter in that it
will limit the queues more. For example, if you set an 82575 device to
VMDQ Mode 2, you will only be able to set 3 RSS queues. See the
following table.

+--------+-------------+
| Model  | VMDQ Mode   |
|========|=============|
| Number | 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

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
-------

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

Valid Range:  0-7

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

The parameters for the driver are referenced by position. Thus, if you
have a dual port adapter, or more than one adapter in your system, and
want "N" virtual functions per port, you must specify a number for
each port with each parameter separated by a comma. This example will
spawn 4 VFs on the first port:

   modprobe igb max_vfs=4

This example will spawn 2 VFs on the first port and 4 VFs on the
second port:

   modprobe igb max_vfs=2,4

Caution:

  Use caution when loading the driver with these parameters. Depending
  on your system configuration, number of slots, etc., it is
  impossible to predict in all cases where the positions would be on
  the command line.

Note:

  Neither the device nor the driver control how VFs are mapped into
  config space. Bus layout will vary by operating system. On operating
  systems that support it, you can check sysfs to find the mapping.

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

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

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

* -1: uses the driver default of allocating memory on whichever
  processor is running modprobe.

The "Node" parameter allows you to choose 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, part of the interrupt time could run on a
different core than where the memory is allocated, causing slower
memory access and impacting throughput, CPU, or both.


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

Valid Range: 0-1

* 0 = Disables EEE

* 1 = Enables EEE

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 at 1 Gbps and 100 Mbps
link speeds.

Note:

  * EEE support requires auto-negotiation.

  * Both link partners must support EEE.

  * EEE is not supported on all Intel(R) Ethernet Network devices or
    at all link speeds.

Example:

   ethtool --show-eee <ethX>
   ethtool --set-eee <ethX> [eee on|off]


DMAC
----

Valid Range: 0, 1, 250, 500, 1000, 2000, 3000, 4000, 5000, 6000, 7000,
8000, 9000, 10000

This parameter enables or disables the DMA Coalescing (DMAC)  feature.
Values are in microseconds and set 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. DMA Coalescing must be enabled across all active ports in order
to save platform power.


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

Valid Range: 0-1

* 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 Features and Configurations
======================================


ethtool
-------

The driver utilizes the ethtool interface for driver configuration and
diagnostics, as well as displaying statistical information. The latest
ethtool version is required for this functionality. Download it at
https://kernel.org/pub/software/network/ethtool/.


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 8 by entering the following:

   dmesg -n 8

Note:

  This setting is not saved across reboots.


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 Base Driver
is igb.

For example, if you install the igb driver for two 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


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 ip command to increase the MTU size. For example, enter the
following where "<ethX>" is the interface number:

   ip link set mtu 9000 dev <ethX>
   ip link set up dev <ethX>

This setting is not saved across reboots.

Add "MTU=9000" to the following file to make the setting change
permanent:

   - For RHEL: ``/etc/sysconfig/network-scripts/ifcfg-<ethX>``
   - For SLES: ``/etc/sysconfig/network/<config_file>``

Note:

  * The maximum MTU setting for jumbo frames is 9216. This corresponds
    to the maximum jumbo frame 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.

  * Packet loss may have a greater impact on throughput when you use
    jumbo frames. If you observe a drop in performance after enabling
    jumbo frames, enabling flow control may mitigate the issue.


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(R) Ethernet 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. 1Gbps
speeds and higher cannot be forced. Use the autonegotiation
advertising setting to manually set devices for 1 Gbps and higher.

Speed, duplex, and autonegotiation advertising are configured through
the ethtool utility.

To see the speed configurations your device supports, run:

   ethtool <ethX>

Caution:

  Only experienced network administrators should force speed and
  duplex or change autonegotiation advertising 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(R) Ethernet 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.


Wake on LAN (WoL) Support
-------------------------

Some adapters do not support Wake on LAN (WoL). To determine if your
adapter supports WoL, run the following command:

   ethtool <ethX>

WoL is configured through the ethtool utility. If your Linux
distribution does not include ethtool, download and install it from
the following website:
https://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 shutdown 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.

  * Wake On LAN is not supported for the Intel(R) 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.

Note:

  * 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_NO_LRO" is a compile time flag. You can enable it at compile time
to add support for LRO from the driver. The flag is used by adding
"CFLAGS_EXTRA="-DIGB_NO_LRO"" to the make file when it's being
compiled:

   make CFLAGS_EXTRA="-DIGB_NO_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:

  LRO does not support IPv6 and UDP.


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

Precision Time Protocol (PTP) is used to synchronize clocks in a
computer network. PTP support varies among Intel devices that support
this driver. Use the following command to get a definitive list of PTP
capabilities supported by the device:

   ethtool -T <ethX>

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
editing the make file as follows 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>


Configuring VLAN Tagging on SR-IOV Enabled Adapter Ports
--------------------------------------------------------

To configure VLAN tagging for the ports on an SR-IOV enabled adapter,
use the following command. The VLAN configuration should be done
before the VF driver is loaded or the VM is booted. The VF is not
aware of the VLAN tag being inserted on transmit and removed on
received frames (sometimes called "port VLAN" mode):

   ip link set dev <ethX> vf <id> vlan <vlan id>

For example, the following will configure PF eth0 and the first VF on
VLAN 10:

   ip link set dev eth0 vf 0 vlan 10


MAC and VLAN Anti-Spoofing Feature for VFs
------------------------------------------

When a malicious driver on a Virtual Function (VF) interface 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
============================


MAC address of Virtual Function changes unexpectedly
----------------------------------------------------

If a Virtual Function's MAC address is not assigned in the host, then
the VF (virtual function) driver will use a random MAC address. This
random MAC address may change each time the VF driver is reloaded. You
can assign a static MAC address in the host machine. This static MAC
address will survive a VF driver reload.


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

If your Intel Ethernet Network Connection is not working after
installing the driver, verify that you have installed the correct
driver.

Intel(R) Active Management Technology 2.0, 2.1, and 2.5 are not
supported in conjunction with the Linux 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 hanging 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.


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.
You should use an OS that fully supports Message Signaled Interrupts
(MSI) and make sure that MSI is enabled in your system's BIOS.


Compiling the driver
--------------------

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 third-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 the following:

   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 file
  "/etc/sysctl.conf":

     net.ipv4.conf.all.arp_filter = 1

Alternatively, you can 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:

   ethtool -A <ethX> 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 should resolve the issue.


Do not use LRO when routing packets
-----------------------------------

Due to a known general compatibility 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 using the
command:

   make CFLAGS_EXTRA=-DAX_RELEASE_CODE=1 install


Rx page allocation errors
-------------------------

The error, "Page allocation failure. order:0," can occur under stress
with kernels 2.6.25 and newer. This is caused by the way the Linux
kernel reports this stressed condition.

Unloading Physical Function (PF) Driver Causes System Reboots When VM
is Running and VF is Loaded on the VM.

Do not unload the PF driver (igb) while VFs are assigned to guests.


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.

Prior to unloading the PF driver, you must first ensure that all VFs
are no longer active. Do this by shutting down all VMs and unloading
the VF driver.


Support
=======

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

You can also visit 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 a supported
kernel with a supported adapter, email the specific information
related to the issue to e1000-devel@lists.sf.net.


License
=======

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".

Copyright(c) 1999 - 2024, Intel Corporation.


Trademarks
==========

Intel is a trademark or registered trademark of Intel Corporation or
its subsidiaries in the United States and/or other countries.

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