Linux* Base Driver for the Gigabit Family of Adapters
Overview
Identifying Your Adapter
Building and Installation
Command Line Parameters
Speed and Duplex Configuration
Additional Configurations
Known Issues
Overview
This file describes the Linux* Base Driver for the Gigabit Family of Adapters. This driver supports the 2.4.x and
2.6.x kernels. This driver includes support for Itanium®
2-based systems.
This driver is only supported as a loadable module. Intel is not supplying
patches against the kernel source to allow for static linking of the driver. 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.
This release includes support for Intel®
I/O Acceleration Technology, Intel®
I/OAT. This is supported on systems using the Intel®
5000 Series Chipsets Integrated Device - 1A38. You can find additional
information on Intel I/OAT at
http://www.intel.com/technology/ioacceleration/index.htm.
The following features are now available in supported kernels:
Channel Bonding documentation can be found in the Linux kernel source:
/documentation/networking/bonding.txt
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.
 |
NOTE: The Intel®
82562v 10/100 Network Connection only
provides 10/100 support.
|
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/network/adapter/pro100/21397.htm
For the latest Intel network drivers for Linux, refer to the following website.
In the search field, enter your adapter name or type, or use the networking link
on the left to search for your adapter:
http://downloadfinder.intel.com/scripts-df/support_intel.asp
Building and Installation
To build a binary RPM* package of this driver, run 'rpmbuild -tb <filename.tar.gz>'.
Replace <filename.tar.gz> with the specific file name of the driver.
 |
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 now.
-
RPM functionality has only
been tested in Red Hat distributions.
|
-
Move the base driver tar file to the directory of your
choice. For example, use '/home/username/e1000' or '/usr/local/src/e1000'.
-
Untar/unzip the archive, where <x.x.x> is the version number for the driver
tar file:
tar zxf e1000-<x.x.x>.tar.gz
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Change to the driver src directory, where <x.x.x> is the version number for the driver
tar:
cd e1000-<x.x.x>/src/
-
Compile the driver module:
make install
The binary will be installed as:
/lib/modules/<KERNEL
VERSION>/kernel/drivers/net/e1000/e1000.[k]o
The install location listed above is the default location.
This may differ for various Linux distributions. For
more information, go to ldistrib.htm.
-
Load the module using either the insmod or modprobe
command:
modprobe e1000
insmod e1000
Note that for 2.6 kernels the insmod command can be used if the full path
to the driver module is specified. For example:
insmod
/lib/modules/<KERNEL VERSION>/kernel/drivers/net/e1000/e1000.ko
With 2.6 based kernels also make sure that older e1000 drivers are removed
from the kernel, before loading the new module:
rmmod e1000; modprobe
e1000
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Assign an IP address to the interface by entering the
following, where <x> is the interface number:
ifconfig eth<x> <IP_address>
-
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>
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 e1000
[<option>=<VAL1>,<VAL2>,...]
For example, with two Gigabit PCI
adapters, entering:
modprobe e1000 TxDescriptors=80,128
loads the e1000 driver with 80 TX descriptors for the first adapter and 128 TX
descriptors for the second adapter.
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 in this document.
-
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.
|
Parameter Name |
Valid Range/Settings |
Default |
Description |
AutoNeg |
0x01-0x0F, 0x20-0x2F |
0x2F |
This parameter is a bit mask that specifies which speed and duplex
settings the board advertises. When this parameter is used, the
Speed and Duplex parameters must not be specified.
This parameter is supported only on adapters using copper connections.
NOTE: Refer to the Speed and Duplex section
of this readme for more
information on the AutoNeg parameter.
|
Duplex |
0-2 (0=auto-negotiate, 1=half, 2=full) |
0 |
Defines the direction in which data is allowed to flow. Can be either
one or two-directional. If both Duplex and the link partner are set to auto-negotiate, the board
auto-detects the correct duplex. If the link partner is forced
(either full or half), Duplex defaults to half-duplex.
This parameter is supported only on adapters using copper connections.
|
FlowControl |
0-3 (0=none, 1=Rx only, 2=Tx only, 3=Rx&Tx) |
Read flow control settings from the EEPROM |
This parameter controls the automatic generation(Tx) and
response(Rx) to Ethernet PAUSE frames. |
InterruptThrottleRate |
(not supported on Intel(R) 82542, 82543 or 82544-based adapters)
Valid Range: 0,1,3,100-100000 (0=off, 1=dynamic, 3=dynamic conservative)
|
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 behaviour 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. The hardware can
handle many more small packets per second however, and for this reason
an adaptive interrupt moderation algorithm was implemented.
Since 7.3.x, 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; and "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
NOTE:
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.
CAUTION:
If you are using the Intel(R) PRO/1000 CT Network Connection (controller
82547), setting InterruptThrottleRate to a value greater than 75,000,
may hang (stop transmitting) adapters
under certain network conditions. If this occurs a NETDEV
WATCHDOG message is logged in the system event log. In
addition, the controller is automatically reset, restoring the network
connection. To eliminate the potential for the hang, ensure that
InterruptThrottleRate is set no greater than 75,000 and is not set to 0.
NOTE:
When e1000 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 e1000 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 RX_POLLING (NAPI) and default driver
settings. |
RxDescriptors |
80-256 for 82542 and 82543-based adapters
80-4096 for all other supported adapters
|
256 |
This value specifies the number of receive buffer descriptors allocated
by the driver. Increasing this value allows the driver to buffer more
incoming packets, at the expense of increased system memory utilization.
Each descriptor is 16 bytes. A receive buffer is also allocated for each
descriptor and can be either 2048, 4096, 8192, or 16384 bytes, depending
on the MTU setting. The maximum MTU size is 16110.
NOTE:
MTU designates the frame size. It only needs to be set for Jumbo Frames.
Depending on the available system resources, the request for a higher
number of receive descriptors may be denied. In this case, use a lower
number.
|
RxIntDelay |
0-65535 (0=off) |
0
|
This value delays the generation of receive interrupts in units of
1.024 microseconds. Receive interrupt reduction can improve CPU
efficiency if properly tuned for specific network traffic.
Increasing this value adds extra latency to frame reception
and can end up decreasing the throughput of TCP traffic. If the system is
reporting dropped receives, this value may be set too high, causing the
driver to run out of available receive descriptors.
CAUTION: When setting RxIntDelay to a value other than 0,
adapters may
hang (stop transmitting) under certain network conditions. If
this occurs a NETDEV WATCHDOG message is logged in the system event log. In
addition, the controller is automatically reset, restoring the
network connection. To eliminate the potential for the hang
ensure that RxIntDelay is set to zero.
|
RxAbsIntDelay |
0-65535 (0=off) |
128 |
This value, in units of 1.024 microseconds, limits the delay in which a
receive interrupt is generated. Useful only if RxIntDelay is non-zero,
this value ensures that an interrupt is generated after the initial
packet is received within the set amount of time. Proper tuning,
along with RxIntDelay, may improve traffic throughput in specific
network conditions.
This parameter is supported only on 82540, 82545 and later adapters.
|
Speed |
0, 10, 100, 1000 |
0 |
Speed forces the line speed to the specified value in megabits per second (Mbps). If this parameter
is not specified or is set to 0 and the link partner is set to auto-negotiate, the board
will auto-detect the correct speed. Duplex must also be set when Speed is set to either 10 or 100.
This parameter is supported only on adapters using copper connections. |
TxDescriptors |
80-256 for 82542 and 82543-based adapters
80-4096 for all other supported adapters
|
256 |
This value is the number of transmit descriptors allocated by the
driver. Increasing this value allows the driver to queue more
transmits. Each descriptor is 16 bytes.
|
TxIntDelay |
0-65535 (0=off) |
64 |
This value delays the generation of transmit interrupts in units of 1.024
microseconds. Transmit interrupt reduction can improve CPU efficiency if
properly tuned for specific network traffic. If the system is reporting
dropped transmits, this value may be set too high causing the driver to run
out of available transmit descriptors. |
TxAbsIntDelay |
0-65535 (0=off) |
64 |
This value, in units of 1.024 microseconds, limits the delay in which a transmit
interrupt is generated. Useful only if TxIntDelay is non-zero, this value
ensures that an interrupt is generated after the initial packet is sent on
the wire within the set amount of time. Proper tuning, along with TxIntDelay,
may improve traffic throughput in specific network conditions.
This parameter is supported only on 82540, 82545 and later adapters.
|
XsumRX |
0-1 |
1 |
A value of '1' indicates that the driver should enable IP checksum
offload for received packets (both UDP and TCP) to the adapter
hardware.
This parameter is not supported on the 82542-based adapter.
|
Copybreak |
0-xxxxxxx (0=off) |
256 |
Usage: insmod e1000.ko copybreak=128
Driver copies all packets below or equaling this size to a fresh rx buffer
before handing it up the stack.
This parameter is different than other parameters, in that it is a single
(not 1,1,1 etc.) parameter applied to all driver instances and it is also
available during runtime at /sys/module/e1000/parameters/copybreak |
Speed and Duplex Configuration
Three keywords are used to control the speed and duplex configuration. These keywords are Speed,
Duplex, and AutoNeg.
If the board uses a fiber interface, these keywords are ignored, and the fiber interface board only links at 1000 Mbps full-duplex.
For copper-based boards, the keywords interact as follows:
The default operation is auto-negotiate. The board advertises all supported
speed and duplex combinations, and it links at the highest common speed and
duplex mode IF the link partner is set to auto-negotiate.
If Speed = 1000, limited auto-negotiation is enabled and only 1000 Mbps is
advertised (The 1000BaseT spec requires auto-negotiation.)
If Speed = 10 or 100, then both Speed and Duplex should be set. Auto-negotiation is disabled,
and the AutoNeg parameter is ignored. Partner SHOULD also be forced.
The AutoNeg parameter is used when more control is required over the
auto-negotiation process. It should be used when you wish to control which speed
and duplex combinations are advertised during the auto-negotiation process.
The parameter may be specified as either a decimal or hexadecimal value as
determined by the bitmap below.
Bit Position |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
Decimal Value |
128 |
64 |
32 |
16 |
8 |
4 |
2 |
1 |
Hex Value |
80 |
40 |
20 |
10 |
8 |
4 |
2 |
1 |
Speed (Mbps): |
N/A |
N/A |
1000 |
N/A |
100 |
100 |
10 |
10 |
Duplex: |
|
|
Full |
|
Full |
Half |
Full |
Half |
Some examples of using AutoNeg:
modprobe e1000 AutoNeg=0x01 (Restricts autonegotiation to 10 Half)
modprobe e1000 AutoNeg=1 (Same as above)
modprobe e1000 AutoNeg=0x02 (Restricts autonegotiation to 10 Full)
modprobe e1000 AutoNeg=0x03 (Restricts autonegotiation to 10 Half or 10 Full)
modprobe e1000 AutoNeg=0x04 (Restricts autonegotiation to 100 Half)
modprobe e1000 AutoNeg=0x05 (Restricts autonegotiation to 10 Half or 100 Half)
modprobe e1000 AutoNeg=0x020 (Restricts autonegotiation to 1000 Full)
modprobe e1000 AutoNeg=32 (Same as above)
Note that when this parameter is used, Speed and Duplex must not be specified.
If the link partner is forced to a specific speed and duplex, then this
parameter should not be used. Instead, use the Speed and Duplex parameters
previously mentioned to force the adapter to the same speed and duplex.
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 e1000.
As an example, if you install the e1000 driver for two Gigabit adapters
(eth0 and eth1) and set the speed and duplex to 10full and 100half, add the
following to modules.conf or /etc/modprobe.conf:
alias eth0 e1000
alias eth1 e1000
options e1000 Speed=10,100 Duplex=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> (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
16110. This value coincides with the maximum Jumbo Frames size of
16128.
-
Some Intel gigabit adapters that support Jumbo Frames
have a frame size limit of 9238 bytes, with a corresponding MTU size
limit of 9216 bytes. The adapters with this limitation are based on the
Intel® 82571EB, 82572EI, 82573L, 82566, 82562, and 80003ES2LAN controllers.
These correspond to the following product names: Intel® PRO/1000 PT Server Adapter Intel® PRO/1000 PT Desktop Adapter Intel® PRO/1000 PT Network Connection Intel® PRO/1000 PT Dual Port Server Adapter Intel® PRO/1000 PT Dual Port Network Connection Intel® PRO/1000 PF Server Adapter Intel® PRO/1000 PF Network Connection Intel® PRO/1000 PF Dual Port Server Adapter Intel® PRO/1000 PB Server Connection Intel® PRO/1000 PL Network Connection Intel® PRO/1000 EB Network Connection with I/O Acceleration Intel® PRO/1000 EB Backplane Connection with I/O Acceleration
Intel® PRO/1000 PT Quad Port Server Adapter Intel® PRO/1000 PF Quad Port Server Adapter Intel® 82566DM-2 Gigabit Network Connection
-
Using Jumbo Frames at 10 or 100 Mbps may result in
poor performance or loss of link.
-
Adapters based on the Intel® 82542 and
82573V/E controller do not support Jumbo Frames. These correspond to
the following product names: Intel® PRO/1000 Gigabit Server Adapter Intel® PRO/1000 PM Network Connection
-
The following adapters do not support Jumbo Frames: Intel® 82562V 10/100 Network Connection Intel® 82566DM Gigabit Network Connection Intel® 82566DC Gigabit Network Connection Intel® 82566MM Gigabit Network Connection Intel® 82566MC Gigabit Network Connection
Intel® 82562GT 10/100 Network Connection Intel® 82562G 10/100
Network Connection
Intel® 82566DC-2 Gigabit Network Connection Intel® 82562V-2 10/100 Network Connection Intel® 82562G-2 10/100 Network Connection Intel® 82562GT-2 10/100 Network Connection
|
Ethtool
The driver utilizes the ethtool interface for driver configuration and
diagnostics, as well as displaying statistical information. Ethtool version 1.6
or later is required for this functionality.
The latest release of ethtool can be found at:
http://sourceforge.net/projects/gkernel.
 |
NOTE: Ethtool 1.6
only supports a limited set of ethtool options. Support for a more complete
ethtool feature set can be enabled by upgrading to the latest version. |
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://sourceforge.net/projects/gkernel.
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 e1000 driver must be
loaded prior to shutting down or suspending the system.
 |
NOTE: Wake On LAN is only supported on port A for the
following devices:
- Intel® PRO/1000 PT Dual Port Network Connection
- Intel® PRO/1000 PT Dual Port Server Connection
- Intel® PRO/1000 PT Dual Port Server Adapter
- Intel® PRO/1000 PF Dual Port Server Adapter
- Intel® PRO/1000 PT Quad Port Server Adapter
|
NAPI
NAPI (Rx polling mode) is supported in the e1000 driver. NAPI is enabled or
disabled based on the configuration of the kernel. To override the
default, use the following compile-time flags.
To enable NAPI, compile the driver module, passing in a configuration option:
make CFLAGS_EXTRA=-DE1000_NAPI install
To disable NAPI, compile the driver module, passing in a configuration
option:
make CFLAGS_EXTRA=-DE1000_NO_NAPI install
See
http://www.cyberus.ca/~hadi/usenix-paper.tgz for more information on NAPI.
Known Issues
 |
NOTE: For distribution-specific information, see ldistrib.htm. |
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 don't 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's BIOS by downloading the Linux Firmware Developer Kit that
can be obtained at http://www.linuxfirmwarekit.org/
82573(V/L/E) TX Unit Hang Messages
Several adapters with the 82573 chipset display "TX unit
hang" messages during normal operation with the e1000 driver.
The issue appears both with TSO enabled and disabled, and is
caused by a power management function that is enabled in the
EEPROM. Early releases of the chipsets to vendors had the EEPROM
bit that enabled the feature. After the issue was discovered
newer adapters were released with the feature disabled in the
EEPROM.
If you encounter the problem in an adapter, and the chipset
is an 82573-based one, you can verify that your adapter needs
the fix by using ethtool:
# ethtool -e eth0
Offset Values
------ ------
0x0000 00 12 34 56 fe dc 30 0d 46 f7 f4 00 ff ff ff ff
0x0010 ff ff ff ff 6b 02 8c 10 d9 15 8c 10 86 80 de 83
^^
The value at offset 0x001e (de) has bit 0 unset. This enables
the problematic power saving feature. In this case, the EEPROM
needs to read "df" at offset 0x001e.
A one-time EEPROM fix is available as a shell script. This
script will verify that the adapter is applicable to the fix and
if the fix is needed or not. If the fix is required, it applies
the change to the EEPROM and updates the checksum. The user must
reboot the system after applying the fix if changes were made to
the EEPROM.
Example output of the script:
# bash fixeep-82573-dspd.sh eth0
eth0: is a "82573E Gigabit Ethernet Controller"
This fixup is applicable to your hardware
executing command: ethtool -E eth0 magic 0x109a8086 offset 0x1e value 0xdf
Change made. You *MUST* reboot your machine before changes take effect!
The script can be downloaded at
http://e1000.sourceforge.net/files/fixeep-82573-dspd.sh
Dropped Receive Packets on Half-duplex 10/100 Networks
If you have an Intel PCI Express adapter running at 10mbps or 100mbps,
half-duplex, you may observe occasional
dropped receive packets. There are no workarounds for this problem in this
network configuration. The network must be updated to operate in full-duplex,
and/or 1000mbps only.
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
Jumbo Frames System Requirement
Memory allocation failures have been observed on Linux systems with 64 MB of
RAM or less that are running Jumbo Frames. If you are using Jumbo Frames, your
system may require more than the advertised minimum requirement of 64 MB of
system memory.
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.
Allocating Rx Buffers when Using Jumbo Frames
Allocating Rx buffers when using Jumbo Frames on 2.6.x kernels may fail if
the available memory is heavily fragmented. This issue may be seen with PCI-X
adapters or with packet split disabled. This can be reduced or eliminated by
changing the amount of available memory for receive buffer allocation, by
increasing /proc/sys/vm/min_free_kbytes.
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 line:
net.ipv4.conf.all.arp_filter = 1
to the file /etc/sysctl.conf
or,
install the interfaces in separate broadcast domains (either in different
switches or in a switch partitioned to VLANs).
|
82541/82547 can't link or is slow to link with some link partners
There is a known compatibility issue with 82541/82547 and some low-end
switches where the link will not be established, or will
be slow to establish. In particular, these switches are known to be incompatible
with 82541/82547:
Planex FXG-08TE
I-O Data ETG-SH8
To workaround this issue, the driver can be compiled with an override of the
PHY's master/slave setting. Forcing master or forcing slave
mode will improve time-to-link.
# make CFLAGS_EXTRA=-DE1000_MASTER_SLAVE=<n>
Where <n> is:
0 = Hardware default
1 = Master mode
2 = Slave mode
3 = Auto master/slave
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 later (including 2.6 kernel), 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.
Last modified on 3/13/07 10:08a Revision 9