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SK98LIN(4) Linux Programmer's Manual SK98LIN(4)

NAME
sk98lin - Marvell/SysKonnect Gigabit Ethernet driver v6.21

SYNOPSIS
insmod sk98lin.o [Speed_A=i,j,...] [Speed_B=i,j,...] [AutoNeg_A=i,j,...] [AutoNeg_B=i,j,...] [DupCap_A=i,j,...]
[DupCap_B=i,j,...] [FlowCtrl_A=i,j,...] [FlowCtrl_B=i,j,...] [Role_A=i,j,...] [Role_B=i,j,...] [ConType=i,j,...]
[Moderation=i,j,...] [IntsPerSec=i,j,...] [PrefPort=i,j,...] [RlmtMode=i,j,...]

DESCRIPTION
sk98lin is the Gigabit Ethernet driver for Marvell and SysKonnect network adapter cards. It supports SysKonnect
SK-98xx/SK-95xx compliant Gigabit Ethernet Adapter and any Yukon compliant chipset.

When loading the driver using insmod, parameters for the network adapter cards might be stated as a sequence of comma
separated commands. If for instance two network adapters are installed and AutoNegotiation on Port A of the first
adapter should be ON, but on the Port A of the second adapter switched OFF, one must enter:

insmod sk98lin.o AutoNeg_A=On,Off

After sk98lin is bound to one or more adapter cards and the /proc file system is mounted on your system, a dedicated
statistics file will be created in folder /proc/net/sk98lin for all ports of the installed network adapter cards. Those
files are named eth[x] whereas x is the number of the interface that has been assigned to a dedicated port by the system.

If loading is finished, any desired IP address can be assigned to the respective eth[x] interface using the ifconfig(8)
command. This causes the adapter to connect to the Ethernet and to display a status message on the console saying "ethx:
network connection up using port y" followed by the configured or detected connection parameters.

The sk98lin also supports large frames (also called jumbo frames). Using jumbo frames can improve throughput
tremendously when transferring large amounts of data. To enable large frames, the MTU (maximum transfer unit) size for
an interface is to be set to a high value. The default MTU size is 1500 and can be changed up to 9000 (bytes). Setting
the MTU size can be done when assigning the IP address to the interface or later by using the ifconfig(8) command with
the mtu parameter. If for instance eth0 needs an IP address and a large frame MTU size, the following two commands might
be used:

ifconfig eth0 10.1.1.1
ifconfig eth0 mtu 9000

Those two commands might even be combined into one:

ifconfig eth0 10.1.1.1 mtu 9000

Note that large frames can only be used if permitted by your network infrastructure. This means, that any switch being
used in your Ethernet must also support large frames. Quite some switches support large frames, but need to be
configured to do so. Most of the times, their default setting is to support only standard frames with an MTU size of
1500 (bytes). In addition to the switches inside the network, all network adapters that are to be used must also be
enabled regarding jumbo frames. If an adapter is not set to receive large frames it will simply drop them.

Switching back to the standard Ethernet frame size can be done by using the ifconfig(8) command again:

ifconfig eth0 mtu 1500

The Marvell/SysKonnect Gigabit Ethernet driver for Linux is able to support VLAN and Link Aggregation according to IEEE
standards 802.1, 802.1q, and 802.3ad. Those features are only available after installation of open source modules which
can be found on the Internet:

VLAN: http://www.candelatech.com/~greear/vlan.html
Link Aggregation: http://www.st.rim.or.jp/~yumo

Note that Marvell/SysKonnect does not offer any support for these open source modules and does not take the
responsibility for any kind of failures or problems arising when using these modules.

Parameters
Speed_A=i,j,...
This parameter is used to set the speed capabilities of port A of an adapter card. It is only valid for Yukon
copper adapters. Possible values are: 10, 100, 1000 or Auto whereas Auto is the default. Usually, the speed is
negotiated between the two ports during link establishment. If this fails, a port can be forced to a specific
setting with this parameter.

Speed_B=i,j,...
This parameter is used to set the speed capabilities of port B of an adapter card. It is only valid for Yukon
copper adapters. Possible values are: 10, 100, 1000 or Auto whereas Auto is the default. Usually, the speed is
negotiated between the two ports during link establishment. If this fails, a port can be forced to a specific
setting with this parameter.

AutoNeg_A=i,j,...
Enables or disables the use of autonegotiation of port A of an adapter card. Possible values are: On, Off or
Sense whereas On is the default. The Sense mode automatically detects whether the link partner supports auto-
negotiation or not.

AutoNeg_B=i,j,...
Enables or disables the use of autonegotiation of port B of an adapter card. Possible values are: On, Off or
Sense whereas On is the default. The Sense mode automatically detects whether the link partner supports auto-
negotiation or not.

DupCap_A=i,j,...
This parameter indicates the duplex mode to be used for port A of an adapter card. Possible values are: Half,
Full or Both whereas Both is the default. This parameter is only relevant if AutoNeg_A of port A is not set to
Sense. If AutoNeg_A is set to On, all three values of DupCap_A ( Half, Full or Both) might be stated. If
AutoNeg_A is set to Off, only DupCap_A values Full and Half are allowed. This DupCap_A parameter is useful if
your link partner does not support all possible duplex combinations.

DupCap_B=i,j,...
This parameter indicates the duplex mode to be used for port B of an adapter card. Possible values are: Half,
Full or Both whereas Both is the default. This parameter is only relevant if AutoNeg_B of port B is not set to
Sense. If AutoNeg_B is set to On, all three values of DupCap_B ( Half, Full or Both) might be stated. If
AutoNeg_B is set to Off, only DupCap_B values Full and Half are allowed. This DupCap_B parameter is useful if
your link partner does not support all possible duplex combinations.

FlowCtrl_A=i,j,...
This parameter can be used to set the flow control capabilities the port reports during auto-negotiation.
Possible values are: Sym, SymOrRem, LocSend or None whereas SymOrRem is the default. The different modes have the
following meaning:

Sym = Symmetric
both link partners are allowed to send PAUSE frames
SymOrRem = SymmetricOrRemote
both or only remote partner are allowed to send PAUSE frames
LocSend = LocalSend
only local link partner is allowed to send PAUSE frames
None = None
no link partner is allowed to send PAUSE frames

Note that this parameter is ignored if AutoNeg_A is set to Off.

FlowCtrl_B=i,j,...
This parameter can be used to set the flow control capabilities the port reports during auto-negotiation.
Possible values are: Sym, SymOrRem, LocSend or None whereas SymOrRem is the default. The different modes have the
following meaning:

Note that this parameter is ignored if AutoNeg_B is set to Off.

Role_A=i,j,...
This parameter is only valid for 1000Base-T adapter cards. For two 1000Base-T ports to communicate, one must take
the role of the master (providing timing information), while the other must be the slave. Possible values are:
Auto, Master or Slave whereas Auto is the default. Usually, the role of a port is negotiated between two ports
during link establishment, but if that fails the port A of an adapter card can be forced to a specific setting
with this parameter.

Role_B=i,j,...
This parameter is only valid for 1000Base-T adapter cards. For two 1000Base-T ports to communicate, one must take
the role of the master (providing timing information), while the other must be the slave. Possible values are:
Auto, Master or Slave whereas Auto is the default. Usually, the role of a port is negotiated between two ports
during link establishment, but if that fails the port B of an adapter card can be forced to a specific setting
with this parameter.

ConType=i,j,...
This parameter is a combination of all five per-port parameters within one single parameter. This simplifies the
configuration of both ports of an adapter card. The different values of this variable reflect the most meaningful
combinations of port parameters. Possible values and their corresponding combination of per-port parameters:

Stating any other port parameter together with this ConType parameter will result in a merged configuration of
those settings. This is due to the fact, that the per-port parameters (e.g. Speed_A) have a higher priority than
the combined variable ConType.

Moderation=i,j,...
Interrupt moderation is employed to limit the maximum number of interrupts the driver has to serve. That is, one
or more interrupts (which indicate any transmit or receive packet to be processed) are queued until the driver
processes them. When queued interrupts are to be served, is determined by the IntsPerSec parameter, which is
explained later below. Possible moderation modes are: None, Static or Dynamic whereas None is the default. The
different modes have the following meaning:

None No interrupt moderation is applied on the adapter card. Therefore, each transmit or receive interrupt is
served immediately as soon as it appears on the interrupt line of the adapter card.

Static Interrupt moderation is applied on the adapter card. All transmit and receive interrupts are queued until
a complete moderation interval ends. If such a moderation interval ends, all queued interrupts are processed in
one big bunch without any delay. The term Static reflects the fact, that interrupt moderation is always enabled,
regardless how much network load is currently passing via a particular interface. In addition, the duration of
the moderation interval has a fixed length that never changes while the driver is operational.

Dynamic Interrupt moderation might be applied on the adapter card, depending on the load of the system. If the
driver detects that the system load is too high, the driver tries to shield the system against too much network
load by enabling interrupt moderation. If -- at a later time -- the CPU utilization decreases again (or if the
network load is negligible) the interrupt moderation will automatically be disabled.

Interrupt moderation should be used when the driver has to handle one or more interfaces with a high network load,
which -- as a consequence -- leads also to a high CPU utilization. When moderation is applied in such high
network load situations, CPU load might be reduced by 20-30% on slow computers.

Note that the drawback of using interrupt moderation is an increase of the round-trip-time (RTT), due to the
queuing and serving of interrupts at dedicated moderation times.

IntsPerSec=i,j,...
This parameter determines the length of any interrupt moderation interval. Assuming that static interrupt
moderation is to be used, an IntsPerSec parameter value of 2000 will lead to an interrupt moderation interval of
500 microseconds. Possible values for this parameter are in the range of 30...40000 (interrupts per second). The
default value is 2000.

This parameter is only used, if either static or dynamic interrupt moderation is enabled on a network adapter
card. This parameter is ignored if no moderation is applied.

Note that the duration of the moderation interval is to be chosen with care. At first glance, selecting a very
long duration (e.g., only 100 interrupts per second) seems to be meaningful, but the increase of packet-processing
delay is tremendous. On the other hand, selecting a very short moderation time might compensate the use of any
moderation being applied.

PrefPort=i,j,...
This parameter is used to force the preferred port to A or B (on dual-port network adapters). The preferred port
is the one that is used if both ports A and B are detected as fully functional. Possible values are: A or B
whereas A is the default.

RlmtMode=i,j,...
RLMT monitors the status of the port. If the link of the active port fails, RLMT switches immediately to the
standby link. The virtual link is maintained as long as at least one "physical" link is up. This parameters
states how RLMT should monitor both ports. Possible values are: CheckLinkState, CheckLocalPort, CheckSeg or
DualNet whereas CheckLinkState is the default. The different modes have the following meaning:

CheckLinkState Check link state only: RLMT uses the link state reported by the adapter hardware for each
individual port to determine whether a port can be used for all network traffic or not.

CheckLocalPort In this mode, RLMT monitors the network path between the two ports of an adapter by regularly
exchanging packets between them. This mode requires a network configuration in which the two ports are able to
"see" each other (i.e., there must not be any router between the ports).

CheckSeg Check local port and segmentation: This mode supports the same functions as the CheckLocalPort mode and
additionally checks network segmentation between the ports. Therefore, this mode is only to be used if Gigabit
Ethernet switches are installed on the network that have been configured to use the Spanning Tree protocol.

DualNet In this mode, ports A and B are used as separate devices. If you have a dual port adapter, port A will be
configured as eth[x] and port B as eth[x+1]. Both ports can be used independently with distinct IP addresses.
The preferred port setting is not used. RLMT is turned off.

Note that RLMT modes CheckLocalPort and CheckLinkState are designed to operate in configurations where a network
path between the ports on one adapter exists. Moreover, they are not designed to work where adapters are
connected back-to-back.

FILES
/proc/net/sk98lin/eth[x]
The statistics file of a particular interface of an adapter card. It contains generic information about the
adapter card plus a detailed summary of all transmit and receive counters.

/usr/src/linux/Documentation/networking/sk98lin.txt
This is the README file of the sk98lin driver. It contains a detailed installation HOWTO and describes all
parameters of the driver. It denotes also common problems and provides the solution to them.

BUGS
Report any bugs to linuxATsyskonnect.de

SEE ALSO
ifconfig(8), insmod(8), modprobe(8)

COLOPHON
This page is part of release 3.25 of the Linux man-pages project. A description of the project, and information about
reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.

Linux 2007-11-25 SK98LIN(4)