nxge - Sun 10/1 Gigabit Ethernet network driver




The nxge Gigabit Ethernet driver is a multi-threaded, loadable, clonable,
GLD-based STREAMS driver supporting the Data Link Provider Interface,
dlpi(4P), on Sun Gigabit Ethernet hardware (NIU, Sun x8, Express Dual 10
Gigabit Ethernet fiber XFP low profile adapter and the 10/100/1000BASE-T
x8 Express low profile adapter).

The nxge driver functions include chip initialization, frame transmit and
receive, flow classification, multicast and promiscuous support, and
error recovery and reporting.

The nxge device provides fully-compliant IEEE 802.3ae 10Gb/s full duplex
operation using XFP-based 10GigE optics (NIU, dual 10 Gigabit fiber XFP
adapter). The Sun Ethernet hardware supports the IEEE 802.3x frame-based
flow control capabilities.

For the 10/100/1000BASE-T adapter, the nxge driver and hardware support
auto-negotiation, a protocol specified by the 1000 Base-T standard.
Auto-negotiation allows each device to advertise its capabilities and
discover those of its peer (link partner). The highest common denominator
supported by both link partners is automatically selected, yielding the
greatest available throughput while requiring no manual configuration.
The nxge driver also allows you to configure the advertised capabilities
to less than the maximum (where the full speed of the interface is not
required) or to force a specific mode of operation, irrespective of the
link partner's advertised capabilities.


The cloning character-special device, /dev/nxge, is used to access all
Sun Neptune NIU devices installed within the system.

The nxge driver is managed by the dladm(8) command line utility, which
allows VLANs to be defined on top of nxge instances and for nxge
instances to be aggregated. See dladm(8) for more details.

You must send an explicit DL_ATTACH_REQ message to associate the opened
stream with a particular device (PPA). The PPA ID is interpreted as an
unsigned integer data type and indicates the corresponding device
instance (unit) number. The driver returns an error (DL_ERROR_ACK) if the
PPA field value does not correspond to a valid device instance number for
the system. The device is initialized on first attach and de-initialized
(stopped) at last detach.

The values returned by the driver in the DL_INFO_ACK primitive in
response to a DL_INFO_REQ are:

o Maximum SDU (default 1500).

o Minimum SDU (default 0). The driver pads to the mandatory
60-octet minimum packet size.

o DLSAP address length is 8.

o MAC type is DL_ETHER.

o SAP length value is -2, meaning the physical address component
is followed immediately by a 2-byte SAP component within the
DLSAP address.

o Broadcast address value is the Ethernet/IEEE broadcast address

Due to the nature of link address definition for IPoIB, the
DL_SET_PHYS_ADDR_REQ DLPI primitive is not supported.

In the transmit case for streams that have been put in raw
mode via the DLIOCRAW ioctl, the dlpi application must prepend
the 20 byte IPoIB destination address to the data it wants to
transmit over-the-wire. In the receive case, applications
receive the IP/ARP datagram along with the IETF defined 4 byte

Once in the DL_ATTACHED state, you must send a DL_BIND_REQ to associate a
particular Service Access Point (SAP) with the stream.


For the 10/100/1000BASE-T adapter, the nxge driver performs auto-
negotiation to select the link speed and mode. Link speed and mode may be
10000 Mbps full-duplex (10 Gigabit adapter), 1000 Mbps full-duplex, 100
Mbps full-duplex, or 10 Mbps full-duplex, depending on the hardware
adapter type. See the IEEE802.3 standard for more information.

The auto-negotiation protocol automatically selects the 1000 Mbps, 100
Mbps, or 10 Mbps operation modes (full-duplex only) as the highest common
denominator supported by both link partners. Because the nxge device
supports all modes, the effect is to select the highest throughput mode
supported by the other device.

You can also set the capabilities advertised by the nxge device using
dladm(8). The driver supports a number of parameters whose names begin
with en_ (see below). Each of these parameters contains a boolean value
that determines if the device advertises that mode of operation. The
adv_autoneg_cap parameter controls whether auto-negotiation is
performed. If adv_autoneg_cap is set to 0, the driver forces the mode
of operation selected by the first non-zero parameter in priority order
as shown below:

(highest priority/greatest throughput)
en_1000fdx_cap 1000Mbps full duplex
en_100fdx_cap 100Mbps full duplex
en_10fdx_cap 10Mbps full duplex
(lowest priority/least throughput)

All capabilities default to enabled. Note that changing any capability
parameter causes the link to go down while the link partners renegotiate
the link speed/duplex using the newly changed capabilities.


Special character device.

32-bit device driver (x86).

64-bit device driver (SPARC).

64-bit device driver (x86).

Configuration file.


See attributes(7) for descriptions of the following attributes:

|Architecture | SPARC, x86 |


streamio(4I), dlpi(4P), driver.conf(5), attributes(7), dladm(8),

Writing Device Drivers

STREAMS Programming Guide

Network Interfaces Programmer's Guide

IEEE 802.3ae Specification -- 2002

April 12, 2008 NXGE(4D)