1 .\" Copyright (c) 2005 Nuno Antunes <nuno.antunes@gmail.com>
2 .\" Copyright (c) 2007 Alexander Motin <mav@FreeBSD.org>
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33 .Nd Committed Access Rate netgraph node type
39 node type limits traffic flowing through it using:
43 Single rate three color marker as described in RFC 2697,
45 Two rate three color marker as described in RFC 2698,
47 RED-like rate limit algorithm used by Cisco,
49 Traffic shaping with RED.
52 This node type supports the following hooks:
53 .Bl -tag -width ".Va upper"
55 Hook leading to upper layer protocols.
57 Hook leading to lower layer protocols.
74 .Sh MODES OF OPERATION
75 Each hook can operate in one of the following modes:
77 .It Dv NG_CAR_SINGLE_RATE
78 Single rate three color marker as described in RFC 2697.
79 Committed burst packets are counted as green, extended burst packets are
80 counted as yellow and exceeding packets are counted as red.
81 Committed burst getting refilled with CIR (Committed Information Rate) speed.
82 When it is full, exceeded burst getting refilled.
83 .It Dv NG_CAR_DOUBLE_RATE
84 Two rate three color marker as described in RFC 2698.
85 Committed burst packets are counted as green, peak burst packets are counted
86 as yellow and exceeding packets are counted as red.
87 Committed burst getting refilled with CIR speed.
88 Peak burst getting refilled with PIR (Peak Information Rate) speed at the
92 .Dv NG_CAR_SINGLE_RATE ,
93 but with different understanding of extended burst.
94 When normal burst exceeded and extended burst is used, packets are counted
95 red with probability equal to part of extended burst consumed.
96 Extended burst getting refilled first.
97 When it is full, committed burst getting refilled.
98 This behavior is similar to RED active queue management algorithm.
100 This algorithm is more polite to the TCP traffic than NG_CAR_SINGLE_RATE.
102 Committed burst packets are counted as green, exceeding packets are delayed
103 by queue with RED management and counted as yellow.
104 Packets dropped by queue counted as red.
105 Queue parameters are hardcoded: length 99 packets, min_th 8 packets, max_p 100%.
107 Traffic shaping is much more polite to the TCP traffic than rate limit on
108 links with bandwidth * delay product less than 6-8 TCP segments, but it
109 consumes additional system resources for queue processing.
111 By default, all information rates are measured in bits per second and bursts
112 are measured in bytes. But when NG_CAR_COUNT_PACKETS option is enabled,
113 rates are measured in packets per second and bursts are in packets.
115 This node type supports the generic control messages and the following
118 .It Dv NGM_CAR_SET_CONF Pq Ic setconf
119 Set node configuration to the specified at
120 .Vt "struct ng_car_bulkconf"
121 .It Dv NGM_CAR_GET_CONF Pq Ic getconf
122 Return current node configuration as
123 .Vt "struct ng_car_bulkconf"
125 struct ng_car_hookconf {
126 uint64_t cbs; /* Commited burst size (bytes) */
127 uint64_t ebs; /* Exceeded/Peak burst size (bytes) */
128 uint64_t cir; /* Commited information rate (bits/s) */
129 uint64_t pir; /* Peak information rate (bits/s) */
130 uint8_t green_action; /* Action for green packets */
131 uint8_t yellow_action; /* Action for yellow packets */
132 uint8_t red_action; /* Action for red packets */
133 uint8_t mode; /* single/double rate, ... */
134 uint8_t opt; /* color-aware or color-blind */
137 /* possible actions (..._action) */
139 NG_CAR_ACTION_FORWARD = 1,
143 /* operation modes (mode) */
145 NG_CAR_SINGLE_RATE = 0,
151 /* mode options (opt) */
152 #define NG_CAR_COUNT_PACKETS 2
154 struct ng_car_bulkconf {
155 struct ng_car_hookconf upstream;
156 struct ng_car_hookconf downstream;
159 .It Dv NGM_CAR_GET_STATS Pq Ic getstats
160 Return node statistics as
161 .Vt "struct ng_car_bulkstats"
163 struct ng_car_hookstats {
164 uint64_t passed_pkts; /* Counter for passed packets */
165 uint64_t droped_pkts; /* Counter for droped packets */
166 uint64_t green_pkts; /* Counter for green packets */
167 uint64_t yellow_pkts; /* Counter for yellow packets */
168 uint64_t red_pkts; /* Counter for red packets */
169 uint64_t errors; /* Counter for operation errors */
172 struct ng_car_bulkstats {
173 struct ng_car_hookstats upstream;
174 struct ng_car_hookstats downstream;
177 .It Dv NGM_CAR_CLR_STATS Pq Ic clrstats
178 Clear node statistics.
179 .It Dv NGM_CAR_GETCLR_STATS Pq Ic getclrstats
180 Atomically return and clear node statistics.
183 This node shuts down upon receipt of a
185 control message, or when all hooks have been disconnected.
187 Limit outgoing data rate over fxp0 Ethernet interface to 20Mbit/s
188 and incoming packet rate to 5000pps.
189 .Bd -literal -offset indent
190 /usr/sbin/ngctl -f- <<-SEQ
191 mkpeer fxp0: car lower lower
192 name fxp0:lower fxp0_car
193 connect fxp0: fxp0_car: upper upper
194 msg fxp0_car: setconf { downstream={ cir=20000000 cbs=2500000 ebs=2500000 greenAction=1 yellowAction=1 redAction=2 mode=2 } upstream={ cir=5000 cbs=100 ebs=100 greenAction=1 yellowAction=1 redAction=2 mode=2 opt=2 } }
202 .%T "A Single Rate Three Color Marker"
207 .%T "A Two Rate Three Color Marker"
211 .An Nuno Antunes Aq nuno.antunes@gmail.com
212 .An Alexander Motin Aq mav@FreeBSD.org
214 At this moment only DROP and FORWARD actions are implemented.