Ubuntu Manpage: nicstat, enicstat - print network traffic statistics

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

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.