Statistics

The following statistics are accessible with kstat(1M). Note that some statistics are available in both 32- and 64-bit counters, in which case the name of the 64 bit statistic will be the same as the 32-bit, but with “64” appended". For example, ipackets64 is the 64-bit version of the ipackets statistic. These are indicated with the special suffix [64] in the table below.

adv_cap_1000fdx

Advertises 1000 Mbps full-duplex support.

adv_cap_1000hdx

Advertises 1000 Mbps half-duplex support.

adv_cap_100fdx

Advertises 100 Mbps full-duplex support.

adv_cap_100hdx

Advertises 100 Mbps half-duplex support.

adv_cap_100T4

Advertises 100BASE-T4 support.

adv_cap_10fdx

Advertises 10 Mbps full-duplex support.

adv_cap_10gfdx

Advertises 10 Gbps support.

adv_cap_10hdx

Advertises 10 Mbps half-duplex support.

adv_cap_autoneg

Advertises auto-negotiation support.

adv_cap_asmpause

Advertises asymmetric flow control support.

adv_cap_pause

Advertises flow control support.

adv_rem_fault

Remote fault status sent to peer.

align_errors

Mis-aligned frames received.

brdcstrcv

Broadcast frames received.

brdcstxmt

Broadcast frames transmitted.

cap_1000fdx

Device supports 1000 Mbps full-duplex.

cap_1000hdx

Device supports 1000 Mbps half-duplex.

cap_100fdx

Device supports 100 Mbps full-duplex.

cap_100hdx

Device supports 100 Mbps half-duplex.

cap_100T4

Device supports 100BASE-T4.

cap_10fdx

Device supports 10 Mbps full-duplex.

cap_10gfdx

Device supports 10 Gpbs.

cap_10hdx

Device supports 10 Mbps half-duplex.

cap_asmpause

Device supports asymmetric flow control.

cap_autoneg

Device supports auto-negotiation.

cap_pause

Device supports symmetric flow control.

cap_rem_fault

Device supports remote fault notification.

carrier_errors

Frames dropped due to loss of link.

collisions

Collisions.

defer_xmts

Transmits deferred due to link activity.

ex_collisions

Frames dropped due to too many collisions.

fcs_errors

Frames received with bad frame checksum.

first_collisions

Frames with at least one collision.

ierrors

Receive errors.

ifspeed

Link speed in bits per second.

ipackets[64]

Frames received successfully.

jabber_errors

Jabber errors.

link_asmpause

Asymmetric flow control; works together with link_pause. See the the description for it below.

link_autoneg

Link was auto-negotiated.

link_duplex

Link duplex status, values as follows:

0	Unknown.
1	Half-duplex.
2	Full-duplex.

link_pause

Link flow control available; works together with link_asmpause. The meanings of these bits are:

pause	asmpause	meaning
0	0	No flow control.
1	0	Symmetric flow control.
0	1	Honor received pause frames.
1	1	Send pause frames when congested.

link_state

Link state; 0 for down, 1 for up.

link_up

Link is up if 1.

lp_cap_1000fdx

Peer supports 1000 Mbps full-duplex.

lp_cap_1000hdx

Peer supports 1000 Mbps half-duplex.

lp_cap_100fdx

Peer supports 100 Mbps full-duplex.

lp_cap_100hdx

Peer supports 100 Mbps half-duplex.

lp_cap_100T4

Peer supports 100BASE-T4.

lp_cap_10fdx

Peer supports 10 Mbps full-duplex.

lp_cap_10gfdx

Peer supports 10 Gbps.

lp_cap_10hdx

Peer supports 10 Mbps half-duplex.

lp_cap_asmpause

Peer supports asymmetric flow control.

lp_cap_autoneg

Peer supports auto-negotiation.

lp_cap_pause

Peer advertises flow control support.

lp_rem_fault

Peer announces a remote fault.

macrv_errors

Generic receive errors.

macxmt_errors

Generic transmit errors.

multi_collisions

Frames with more than one collision.

multircv

Multicast frames received.

multixmt

Multicast frames transmitted.

norcvbuf

Receive frames dropped due to lack of resources.

noxmtbuf

Transmit frames dropped due to lack of resources.

obytes[64]

Bytes (octets) transmitted successfully.

oerrors

Transmit errors.

oflo

Overflow errors.

opackets[64]

Frames successfully transmitted.

promisc

Interface is in promiscuous mode.

rbytes[64]

Bytes (octets) received successfully.

runt_errors

Frames received that were too short.

sqe_errors

Squelch errors.

toolong_errors

Frames received that were too long.

tx_late_collisions

Late collisions on transmit.

uflo

Underflow errors.

unknowns

Frames received with no local recipient.

xcvr_addr

Transceiver address.

xcvr_id

Transceiver vendor and device ID.

xcvr_inuse

Identifies the type of transceiver in use. Values are as follows:

0	Unknown or undefined.
1	None.
2	10 Mbps
3	100BASE-T4
4	100BASE-X
5	100BASE-T2
6	1000BASE-X
7	1000BASE-T

Properties

The following parameters are accessible with dladm(1M). Some of these are normally only read-only. Other properties that are not specific to IEEE 802.3 / Ethernet links are also available via dladm(1M), and are documented in its man page rather than here.

speed

Link speed, in Mbps per second (dladm only).

duplex

Link duplex, either "full" or "half".

state

Link state, either "up" or "down".

mtu

Maximum link frame size in bytes. See Jumbo Frames.

flowctrl

Flow control setting, one of "no", "tx", "rx", or "bi". See Flow Control.

adv_10gfdx_cap

Advertising 10 Gbps support.

en_10gfdx_cap

Enable 10 Gbps support.

adv_1000fdx_cap

Advertising 1000 Mbps full-duplex support.

en_1000fdx_cap

Enable 1000 Mbps full-duplex.

adv_1000hdx_cap

Advertising 1000 Mbps half-duplex support.

en_1000hdx_cap

Enable 1000 Mbps half-duplex.

adv_100fdx_cap

Advertising 100 Mbps full-duplex support.

en_100fdx_cap

Enable 100 Mbps full-duplex.

adv_100hdx_cap

Advertising 100 Mbps half-duplex support.

en_100hdx_cap

Enable 100 Mbps half-duplex.

adv_10fdx_cap

Advertising 10 Mbps full-duplex support.

en_10fhdx_cap

Enable 100 Mbps full-duplex.

adv_10hdx_cap

Advertising 10 Mbps half-duplex support.

en_10fhdx_cap

Enable 10 Mbps half-duplex.

Auto-negotiation

With modern devices, auto-negotiation is normally handled automatically. With 10 Gbps and 1000 Gbps, it is mandatory. (10GBASE-T also requires full-duplex operation.) It is also strongly recommended for use whenever possible; without auto-negotiation the link will usually not operate unless both partners are configured to use the same link mode.

Auto-negotiation, when enabled, takes place by comparing the local capabilities that have been advertised (which must also be supported by the local device), with the capabilities that have been advertised by the link partner (peer). The first of the following modes that is supported by both partners is selected as the link negotiation result:

• 10 Gbps (10gfdx)
• 1000 Mbps full-duplex (1000fdx)
• 1000 Mbps half-duplex (1000hdx)
• 100 Mbps full-duplex (100fdx)
• 100BASE-T4 (100T4)
• 100 Mbps half-duplex (100hdx)
• 10 Mbps full-duplex (10fdx)
• 10 Mbps half-duplex (10hdx)

Advertisement of these modes can be enabled or disabled by setting the appropriate en_ property in dladm(1M).

Auto-negotation may also be disabled, by setting the adv_autoneg_cap property to 0. In this case, the highest enabled link mode (using the above list) is “forced” for the link.

Flow Control

Link layer flow control is available on many modern devices, and is mandatory for operation at 10 Gbps. It requires that the link be auto-negotiated, and that the link be full-duplex, in order to function.

Flow control is applied when a receiver becomes congested. In this case the receiver can send a special frame, called a pause frame, to request its partner cease transmitting for a short period of time.

Flow control can be said to be either symmetric, in which case both partners can send and honor pause frames, or asymmetric, in which case one partner may not transmit pause frames.

The flow control mode used is driven by the flowctrl property. It has the following meanings:

"no"	Neither send, nor honor pause frames.
"tx"	Send pause frames, provided that the peer can support them, but do not honor them.
"rx"	Receive and honor pause frames.
"bi"	Both send and receive (and honor) pause frames.

The statistics for flow control (adv_cap_pause, adv_cap_asmpause, lp_cap_pause, lp_cap_asmpause, link_pause, and link_asmpause) are based on the properties exchanged in the auto-negotiation and are confusing as a result. Administrators are advised to use the flowctrl property instead.

Jumbo Frames

The IEEE 802.3 standard specifies a standard frame size of 1518 bytes, which includes a 4-byte frame checksum, a 14-byte header, and 1500 bytes of payload. Most devices support larger frame sizes than this, and when all possible parties on the same local network can do so, it may be advantageous to choose a larger frame size; 9000 bytes is the most common option, as it allows a transport layer to convey 8 KB (8192) of data, while leaving room for various link, network, and transport layer headers.

Note that the use of frames carrying more than 1500 bytes of payload is not standardized, even though it is common practice.

The mtu property is used to configure the frame size. Note that this is the size of the payload, and excludes the preamble, checksum, and header. It also excludes the tag for devices that support tagging (see Virtual LANs below).

Care must be taken to ensure that all communication parties agree on the same size, or communication may cease to function properly.

Note that the mtu property refers to the link layer property. It may be necessary to configure upper layer protocols such as IP to use a different size when this changes. See ifconfig(1M).

Virtual LANs

Most devices support virtual LANs (and also priority control tagging) though the use of a 4-byte tag inserted between the frame header and payload. The details of configuration of this are covered in the dladm(1M) manual.

Data Link Provider Interface (DLPI) Details

The correct method for applications to access Ethernet devices directly is to use the DLPI. See dlpi(7P) and libdlpi(3LIB) for further information.

The following DLPI parameters are presented to applications.

Maximum SDU	1500 (or larger, as determined by the mtu property.)
Minimum SDU	0
Address length	6
MAC type	DL_ETHER
SAP length	−2
Service mode	DL_CLDLS
Broadcast address	ff:ff:ff:ff:ff:ff (6 bytes with all bits set)

Note that if the application binds to SAP of 0, then standard IEEE 802.3 mode is assumed and the frame length is stored in place of the Ethernet type. Frames that arrive with the type field set to 1500 or less, are delivered to applications that bind to SAP 0.

Ethernet drivers on the support both DLPI style 1 and style 2 operation. Additionally, it is possible to configure provide “vanity” names to interfaces using the dladm(1M) rename-link subcommand. Such vanity names are only accessible using DLPI style 1.