108 lines
4.0 KiB
Groff
Executable File
108 lines
4.0 KiB
Groff
Executable File
.TH QOS 7 "April 20, 2000" "Linux" "Miscellaneous"
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.SH NAME
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qos \- Quality of Service specification
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.SH DESCRIPTION
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The \fBtext2qos\fP and \fBqos2text\fP functions use the format described
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in this man page. Because all standard ATM tools on Linux use those
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functions to convert to or from the textual representation of QOS
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specifications, they expect them in the same format too.
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.P
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The most fundamental parameters are the \fItraffic class\fP and the
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\fIAAL (ATM Adaption Layer) type\fP. If the
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connection is bi-directional, both directions have the same traffic
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class and the same AAL type. The traffic class and the AAL type are the first
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elements (in any order) in a QOS specification. The traffic class is the only
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required element. If the AAL type is omitted, the application will provide a
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default value. The following traffic classes are recognized:
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.IP \fBubr\fP
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Unassigned Bit Rate
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.IP \fBcbr\fP
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Constant Bit Rate
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.IP \fBabr\fP
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Available Bit Rate
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.P
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The following AAL types are recognized:
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.IP \fBaal0\fP
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("raw ATM")
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.IP \fBaal5\fP
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.P
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If both, the traffic class and the AAL type are specified, they are separated
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by a comma.
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.P
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If more parameters are supplied, the traffic class and AAL type must be
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followed by a colon. Traffic parameters can be specified independently for
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the transmit and the receive direction. Their parameter lists are prefixed
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with \fBtx:\fP and \fBrx:\fP, respectively. If both parameter lists are
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present, the \fBtx:\fP list must precede the \fBrx:\fP list. If a
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parameter is equal for both directions, it can be placed in a common
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parameter list (without prefix). The general format is as follows:
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.P
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\fIclass_and_aal\fB:\fIcommon_list\fP,tx:\fIlist\fB,rx:\fIlist\fP
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.P
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Each list consists of elements specifying a parameter. Elements can
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appear in any order and they are separated with commas. The following
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elements are recognized:
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.IP \fBpcr=\fIrate\fP
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is a synonym for \fBmax_pcr=\fIrate\fP
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.IP \fBmax_pcr=\fIrate\fP
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The upper limit for the peak cell rate to assign. If omitted, any rate up
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to link speed may be chosen.
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.IP \fBmin_pcr=\fIrate\fP
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The lower limit for the peak cell rate to assign. If omitted, any rate above
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zero can be chosen.
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.IP \fBsdu=\fIsize\fP
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is a synonym for \fBmax_sdu=\fIsize\fP
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.IP \fBmax_sdu=\fIsize\fP
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The size of the largest packet that may be sent or received. If omitted,
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a context-dependent default value is used.
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.P
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Values are specified as follows:
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.IP \fIrate\fP
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The (decimal) rate, optionally followed by a unit. The unit may be prefixed
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with one of the multipliers \fBk\fP, \fBM\fP, or \fBG\fP, meaning 1'000,
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1'000'000, or 1'000'000'000, respectively. The units \fBcps\fP
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(cells per second) and \fBbps\fP (bits per second) are recognized. If
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multiplier and unit are omitted, cells per second are assumed. Note
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that the rate is always converted to cells per second, so rounding errors
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may occur when specifying the rate in bits per second. Rates measured in
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bits per second are considered to be user data rates, i.e. one cell
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corresponds to 384 bits. The rate can be a fractional value, e.g.
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\fB1.3Mbps\fP. It is an error to specify only a
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multiplier without a unit. Link speed can be indicated by using the keyword
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\fBmax\fP as the rate.
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.IP \fIsize\fP
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The (decimal) number of bytes.
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.P
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The \fBtx:\fP or \fBrx:\fP lists may also just contain the single element
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\fBnone\fP, which indicates that the corresponding direction is not used.
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It is an error to specify \fBnone\fP for both direction.
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.P
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Note that commas must never follow colons or other commas. Also,
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whitespace is not allowed inside a QOS specification. QOS specifications
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are case-insensitive.
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.SH EXAMPLES
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Each of the following lines contains a valid QOS specification:
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.nf
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.sp
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ubr
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ubr:pcr=100kbps
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cbr,aal0:pcr=64kbps
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CBR:max_pcr=11Mbps,min_pcr=10mbps,sdu=8192
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aal5,ubr:tx:none
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cbr:tx:pcr=30000,rx:none
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.sp
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.fi
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The following specificiations are equivalent:
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.nf
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.sp
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CBR,AAL5:PCR=48Mbps
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cbr,aal5:max_pcr=125000
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cbr,aal5:tx:pcr=125kcps,rx:pcr=125kcps
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.sp
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.fi
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.SH AUTHOR
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Werner Almesberger, EPFL LRC/ICA <werner.almesberger@epfl.ch>
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.\" .SH "SEE ALSO"
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.\" atmsigd(8), syslogd(8)
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.\"{{{}}}
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