204 lines
6.3 KiB
Groff
204 lines
6.3 KiB
Groff
.\" Copyright (c) 2005 Nuno Antunes <nuno.antunes@gmail.com>
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.\" Copyright (c) 2007 Alexander Motin <mav@FreeBSD.org>
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd March 11, 2007
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.Dt NG_CAR 4
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.Os
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.Sh NAME
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.Nm ng_car
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.Nd Commited Access Rate netgraph node type
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.Sh SYNOPSIS
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.In netgraph/ng_car.h
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.Sh DESCRIPTION
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The
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.Nm car
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node type limits traffic flowing through it using:
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.Pp
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.Bl -bullet -compact
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.It
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Single rate three color marker as described in RFC 2697,
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.It
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Two rate three color marker as described in RFC 2698,
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.It
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RED-like rate limit algorithm used by Cisco,
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.It
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Traffic shaping with RED.
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.El
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.Sh HOOKS
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This node type supports the following hooks:
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.Bl -tag -width indent
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.It Va upper
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Hook leading to upper layer protocols.
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.It Va lower
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Hook leading to lower layer protocols.
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.El
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.Pp
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Traffic flowing from
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.Va upper
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to
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.Va lower
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is considered
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.Sy downstream
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traffic.
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Traffic flowing from
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.Va lower
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to
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.Va upper
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is considered
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.Sy upstream
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traffic.
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.Sh MODES OF OPERATION
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Each hook can operate in one of the following modes:
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.Bl -tag -width indent
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.It Dv NG_CAR_SINGLE_RATE
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Single rate three color marker as described in RFC 2697.
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Committed burst packets are counted as green, extended burst packets are
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counted as yellow and exceeding packets are counted as red.
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Committed burst getting refilled with CIR (Committed Information Rate) speed.
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When it is full, exceeded burst getting refilled.
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.It Dv NG_CAR_DOUBLE_RATE
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Two rate three color marker as described in RFC 2698.
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Committed burst packets are counted as green, peak burst packets are counted
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as yellow and exceeding packets are counted as red.
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Committed burst getting refilled with CIR speed.
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Peak burst getting refilled with PIR (Peak Information Rate) speed at the
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same time.
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.It Dv NG_CAR_RED
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Similar to
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.Dv NG_CAR_SINGLE_RATE ,
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but with different understanding of extended burst.
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When normal burst exceeded and extended burst is used, packets are counted
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red with probability equal to part of extended burst consumed.
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Extended burst getting refilled first.
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When it is full, committed burst getting refilled.
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This behavior is similar to RED active queue management algorithm.
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.Pp
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This algorithm is more polite to the TCP traffic than NG_CAR_SINGLE_RATE.
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.It Dv NG_CAR_SHAPE
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Committed burst packets are counted as green, exceeding packets are delayed
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by queue with RED management and counted as yellow.
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Packets dropped by queue counted as red.
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Queue parameters are hardcoded: length 99 packets, min_th 8 packets, max_p 100%.
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.Pp
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Traffic shaping is much more polite to the TCP traffic than rate limit on
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links with bandwidth * delay product less than 6-8 TCP segments, but it
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consumes additional system resources for queue processing.
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.El
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By default, all information rates are measured in bits per second and bursts
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are measured in bytes. But when NG_CAR_COUNT_PACKETS option is enabled,
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rates are measured in packets per second and bursts are in packets.
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.Sh CONTROL MESSAGES
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This node type supports the generic control messages and the following
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specific messages.
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.Bl -tag -width indent
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.It Dv NGM_CAR_SET_CONF Pq Li setconf
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Set node configuration to the specified at
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.Vt "struct ng_car_bulkconf"
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.It Dv NGM_CAR_GET_CONF Pq Li getconf
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Return current node configuration as
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.Vt "struct ng_car_bulkconf"
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.Bd -literal
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struct ng_car_hookconf {
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u_int64_t cbs; /* Committed burst size */
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u_int64_t ebs; /* Exceeded/Peak burst size */
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u_int64_t cir; /* Committed information rate */
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u_int64_t pir; /* Peak information rate */
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u_int8_t green_action; /* Action for green packets */
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u_int8_t yellow_action; /* Action for yellow packets */
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u_int8_t red_action; /* Action for red packets */
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u_int8_t mode; /* operation mode */
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u_int8_t opt; /* mode options */
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};
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/* possible actions (..._action) */
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enum {
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NG_CAR_ACTION_FORWARD = 1,
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NG_CAR_ACTION_DROP
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};
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/* operation modes (mode) */
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enum {
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NG_CAR_SINGLE_RATE = 0,
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NG_CAR_DOUBLE_RATE,
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NG_CAR_RED,
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NG_CAR_SHAPE
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};
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/* mode options (opt) */
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#define NG_CAR_COUNT_PACKETS 2
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struct ng_car_bulkconf {
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struct ng_car_hookconf upstream;
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struct ng_car_hookconf downstream;
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};
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.Ed
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.It Dv NGM_CAR_GET_STATS Pq Li getstats
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Return node statistics as
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.Vt "struct ng_car_bulkstats"
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.Bd -literal
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struct ng_car_hookstats {
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u_int64_t passed_pkts;
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u_int64_t droped_pkts;
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u_int64_t green_pkts;
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u_int64_t yellow_pkts;
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u_int64_t red_pkts;
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u_int64_t errors;
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};
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struct ng_car_bulkstats {
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struct ng_car_hookstats upstream;
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struct ng_car_hookstats downstream;
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};
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.Ed
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.It Dv NGM_CAR_CLR_STATS Pq Li clrstats
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Clear node statistics.
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.It Dv NGM_CAR_GETCLR_STATS Pq Li getclrstats
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Atomically return and clear node statistics.
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.El
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.Sh SHUTDOWN
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This node shuts down upon receipt of a
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.Dv NGM_SHUTDOWN
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control message, or when all hooks have been disconnected.
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.Sh SEE ALSO
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.Xr netgraph 4 ,
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.Xr ngctl 8
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.Rs
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.%A J. Heinanen
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.%T "A Single Rate Three Color Marker"
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.%O RFC 2697
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.Re
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.Rs
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.%A J. Heinanen
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.%T "A Two Rate Three Color Marker"
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.%O RFC 2698
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.Re
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.Sh AUTHORS
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.An Nuno Antunes Aq nuno.antunes@gmail.com
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.An Alexander Motin Aq mav@FreeBSD.org
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.Sh BUGS
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At this moment only DROP and FORWARD actions are implemented.
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