tokenmt(7ipp)

1tokenmt(7ipp)            IP Quality of Service Modules           tokenmt(7ipp)
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NAME

6       tokenmt - Single and Two Rate Three Conformance Level Meter
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DESCRIPTION

9       The  tokenmt  module can be configured as a Single or a Two Rate meter.
10       Packets are deemed to belong to one of the three levels -  Red,  Yellow
11       or  Green  -  depending  on the configured rate(s) and the burst sizes.
12       When configured as a Single Rate meter, tokenmt can operate  with  just
13       the Green and Red levels.
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16       Configuration  parameters for tokenmt correspond to definitions in RFC-
17       2697 and RFC- 2698 as follows:
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20       Configuring tokenmt as a Single Rate meter (from RFC- 2697):
21         committed_rate - CIR
22         committed_burst - CBS
23         peak_burst - EBS
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26       (thus 'peak_burst' for a single rate  meter  is  actually  the  'excess
27       burst'  in  the  RFC.  However,  throughout the text the parameter name
28       "peak burst" is used.)
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31       Configuring tokenmt as a Two Rate meter (from RFC- 2698):
32         committed_rate - CIR
33         peak_rate - PIR
34         committed_burst - CBS
35         peak_burst - PBS
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38       The meter is implemented using token buckets C and P,  which  initially
39       hold tokens equivalent to committed and peak burst sizes (bits) respec‐
40       tively. When a packet of size  B bits arrive at time  t, the  following
41       occurs:
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43         When operating as a Single Rate meter, the outcome (level)
44         is decided as follows:
45                 - Update tokens in C and P
46                       o Compute no. of tokens accumulated since the
47                         last time packet was seen at the committed rate as
48                         T(t) = committed rate * (t - t')
49                         (where t' is the time the last packet was seen)
50                       o Add T tokens to C up to a maximum of committed burst
51                         size. Add remaining tokens ((C+T) - Commited Burst),
52                         if any, to P, to a maximum of peak burst size.
53                 - Decide outcome
54                       o If not color aware
55                               o If B <= C, outcome is GREEN and C -= B.
56                               o Else, if B <= P, outcome is YELLOW and P -= B.
57                               o Else, outcome is Red.
58                       o Else,
59                               o obtain DSCP from packet
60                               o obtain color from color_map, color_map[DSCP]
61                               o if (color is GREEN) and (B <= C), outcome is
62                                 GREEN and C -= B.
63                               o Else, if (color is GREEN or YELLOW) and
64                                 (B <= P), outcome is YELLOW and  P -= B.
65                               o Else, outcome is RED.
66              Note that if peak_burst and yellow_next_actions are
67              not specified (that is, a single rate meter with two
68              outcomes), the outcome is never YELLOW.
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72       When  operating  as a Two Rate meter, the outcome (level) is decided as
73       follows:
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75         - Update tokens in C and P
76                           o Compute no. of tokens accumulated since the last time a
77                             packet was seen at the committed and peak rates as
78                             Tc(t) = committed rate * (t - t')
79                             Tp(t) = peak rate * (t - t')
80                             (where t' is the time the last packet was seen)
81                           o Add Tc to C up to a maximum of committed burst size
82                           o Add Tp to P up to a maximum of peak burst size
83                      - Decide outcome
84                           o If not color aware
85                                 o If B > P, outcome is RED.
86                                 o Else, if B > C, outcome is YELLOW and P -= B
87                                 o Else, outcome is GREEN and C -= B & P -= B
88                           o Else,
89                                 o obtain DSCP from packet
90                                 o obtain color from color_map, color_map[DSCP]
91                                 o if (color is RED) or (B > P), outcome is RED
92                                 o Else, if (color is YELLOW) or (B > C),
93                                   outcome is YELLOW and P -= B
94                                 o Else, outcome is GREEN and C -= B & P -= B
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STATISTICS

98       The tokenmt module exports the following statistics through kstat:
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101       Global statistics:
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103         module: tokenmt                          instance: <action id>
104           name: tokenmt statistics               class <action name>
105                 epackets                         <number of packets in error>
106                 green_bits                       <number of bits in green>
107                 green_packets                    <number of packets in green>
108                 red_bits                         <number of bits in red>
109                 red_packets                      <number of packets in red>
110                 yellow_bits                      <number of bits in yellow>
111                 yellow packets                   <number of packets in yellow>
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FILES

115       /kernel/ipp/sparcv9/tokenmt
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117           64-bit module (SPARC only.)
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ATTRIBUTES

121       See attributes(5) for descriptions of the following attributes:
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126       ┌─────────────────────────────┬─────────────────────────────┐
127       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
128       ├─────────────────────────────┼─────────────────────────────┤
129       │Availability                 │SUNWqos                      │
130       └─────────────────────────────┴─────────────────────────────┘
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NAME

DESCRIPTION

STATISTICS

FILES

ATTRIBUTES

SEE ALSO