nicstat(1)

NAME
nicstat, enicstat - print network traffic statistics

SYNOPSIS
nicstat [-hvnsxpztualkMU] [-iinterface] [-Sint:mbps[fd|hd]] [interval [count]]

enicstat <same options & operands>

DESCRIPTION
nicstat prints out network statistics for all network cards (NICs), including packets, kilobytes per second, average packet sizes and more.

OPTIONS

-h  Display brief usage information (help).

-v  Display nicstat version (and additional fields when combined with '-l')

-n  Show statistics for non-local (i.e. non-loopback) interfaces only.

-s  Display summary output - just the amount of data received (read) and transmitted (written).

-x  Display extended output. See OUTPUT section for details.

-U  Display separate read and write utilization statistics. This affects the default, extended (-x) and all (-a) format outputs. For the default format the "Sat" statistic is dropped to fit the output in 80 columns.

-M  Display interface throughput statistics in Mbps (megabits per second), instead of the default KB/s (kilobytes per second). NOTE - interface statistics are reported to operating systems in bytes. nicstat does not know if Ethernet or other hardware overheads are included in the statistic on each platform.

-p  Display output in parseable format. This outputs one line per interface, in the following formats (which correspond to the default, -x, -t and -u options; respectively):

time:In:rKB/s:wKB/s:rPk/s:wPk/s:%Util:Sat
    time:In:rKB/s:wKB/s:rPk/s:wPk/s:%Util:Sat:IErr:OErr:Coll:NoCP:Defer time:TCP:InKB:OutKB:InSeg:OutSeg:Reset:AttF:%ReTX:InConn:OutCon:Drops time:UDP:InDG:OutDG:InErr:OutErr

    where time is the number of seconds since midnight, Jan 1 1970 (UST) and the other fields are as described in the OUTPUT section below. NOTE - throughput statistics are always in KB/s (kilbytes per second) for parseable formats, even if the "-M" flag has been specified.

-z  Skip interfaces for which there was zero traffic for the sample period.

-t  Show TCP statistics.

-u  Show UDP statistics.

-a  Equvalent to '-x -t -u'.

-l  Just list interfaces.

-iinterface[,interface...]
    Show statistics for only the interface(s) listed. Multiple interfaces can be listed, separated by commas (,).

-Sint:speed[fd|hd]
    (Linux only). Specify the speed (and optionally duplex mode) of one or more interfaces. The given speed(s) are in megabits/second. The duplex mode will default to "full" unless a suffix beginning with "h" or "H" is specified. Speed and duplex mode are obtained automatically on Solaris using the "ifspeed" and "link_duplex" kstat values.

-k  (Solaris only). Search for active network interfaces by looking for kstat "link_state" statistics with a value of 1. This is only of value on systems running Solaris 10 (or early releases of Solaris 11 Express), with Exclusive IP Zones, where the interfaces given to an Exclusive IP Zone are not otherwise visible. If you are running Solaris 9 (or earlier), or Solaris 11 (or later) you do not need this option.

OPERANDS

interval
    Specifies the number of seconds between samples.

count
    Specifies the number of times that the statistics are repeated. If no count is specified, nicstat will repeat statistics indefinitely.

OUTPUT
The fields of nicstat's display are:

Time
    The time corresponding to the end of the sample shown, in HH:MM:SS format (24-hour clock).

Int The interface name.

rKB/s, InKB
    Kilobytes/second read (received).

wKB/s, OutKB
    Kilobytes/second written (transmitted).

rMbps, RdMbps
    Megabits/second read (received).

wMbps, WrMbps
    Megabits/second written (transmitted).

rPk/s, InSeg, InDG
    Packets (TCP Segments, UDP Datagrams)/second read (received).

wPk/s, OutSeg, OutDG
    Packets (TCP Segments, UDP Datagrams)/second written (transmitted).

rAvs
    Average size of packets read (received).

wAvs
    Average size of packets written (transmitted).

%Util
    Percentage utilization of the interface. For full-duplex interfaces, this is the greater of rKB/s or wKB/s as a percentage of the interface speed. For half-duplex interfaces, rKB/s and wKB/s are summed.

%rUtil, %wUtil
    Percentage utilization for bytes read and written, respectively.

Sat Saturation. This the number of errors/second seen for the interface - an indicator the interface may be approaching saturation. This statistic is combined from a number of kernel statistics. It is recommended to use the '-x' option to see more individual statistics (those mentioned below) when attempting to diagnose a network issue.

IErr
    Packets received that could not be processed because they contained errors

OErr
    Packets that were not successfully transmitted because of errors

Coll
    Ethernet collisions during transmit.

NoCP
    No-can-puts. This is when an incoming packet can not be put to the process reading the socket. This suggests the local process is unable to process incoming packets in a timely manner.

Defer
    Defer Transmits. Packets without collisions where first transmit attempt was delayed because the medium was busy.

Reset
    tcpEstabResets. The number of times TCP connections have made a direct transition to the CLOSED state from either the ESTABLISHED state or the CLOSE-WAIT state.

AttF
    tcpAttemptFails - The number of times that TCP connections have made a direct transition to the CLOSED state from either the SYN-SENT state or the SYN-RCVD state, plus the number of times TCP connections have made a direct transition to the LISTEN state from the SYN-RCVD state.

%ReTX
    Percentage of TCP segments retransmitted - that is, the number of TCP segments transmitted containing one or more previously transmitted octets.

InConn
    tcpPassiveOpens - The number of times that TCP connections have made a direct transition to the SYN-RCVD state from the LISTEN state.

OutCon
    tcpActiveOpens - The number of times that TCP connections have made a direct transition to the SYN-SENT state from the CLOSED state.

Drops
    tcpHalfOpenDrop + tcpListenDrop + tcpListenDropQ0.

tcpListenDrop and tcpListenDropQ0 - Number of connections dropped from the completed connection queue and incomplete connection queue, respectively. tcpHalfOpenDrops - Number of connections dropped after the initial SYN packet was received.

The first set of statistics printed are averages since system boot. If no interval operand is specified, or a count value of "1" is specified, this will be the only sample printed.

EXAMPLES
Print average statistics from boot time to now only:

	$ nicstat

Print statistics for all interfaces, every 3 seconds:

	$ nicstat 3

Print statistics for all interfaces, every 5 seconds, finishing after 10 samples:

	$ nicstat 5 10

Print statistics every 3 seconds, only for interfaces "hme0" and "hme1":

	$ nicstat -i hme0,hme1 3

Print statistics for non-local interfaces, setting speed of "eth0" and "eth1" to 10mbps/half-duplex and 1000mbps/full-duplex, respectively:

	$ nicstat -n -S eth0:10h,eth1:1000 5

SEE ALSO
netstat(1M) kstat(1M), kstat(3KSTAT), mibiisa(1M), ethtool(8) "nicstat - the Solaris and Linux Network Monitoring Tool You Did Not Know You Needed" -http://blogs.oracle.com/timc/entry/nicstat_the_solaris_and_linux

NOTES

On Linux, the NoCP, Defer, TCP InKB, and TCP OutKB statistics are always reported as zero.

The way that saturation is reported is a best effort, as there is no standardized naming to capture all errors related to an interface's inability to receive or transmit a packet. Monitoring %Util and packet rates, along with an understanding of the specific NICs may be more useful in judging whether you are nearing saturation.

The -S option is provided for the Linux edition as nicstat requires super-user privilege to obtain speed and duplex mode information for interfaces. If you are unable to set up nicstat as setuid-root, a script named enicstat is available, which uses the ethtool utility then calls nicstat with an -S value. ethtool itself requires super-user privilege for this to work.