1..::lib::Smokeping::matchers::MedratSimoo.(k.3e:)P:ilnigb::Smokeping::matchers::Medratio(3)
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NAME

6       Smokeping::matchers::Medratio - detect changes in the latency median
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OVERVIEW

9       The Medratio matcher establishes a historic median latency over several
10       measurement rounds. It compares this median, against a second median
11       latency value again build over several rounds of measurement.
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13       By looking at the median value this matcher is largly imune against
14       spikes and will only react to long term developments.
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DESCRIPTION

17       Call the matcher with the following sequence:
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19        type = matcher
20        pattern =  Medratio(historic=>a,current=>b,comparator=>o,percentage=>p)
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22       historic
23           The number of values to use for building the 'historic' median.
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25       current
26           The number of values to use for building the 'current' median.
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28       comparator
29           Which comparison operator should be used to compare
30           current/historic with percentage.
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32       percentage
33           Right hand side of the comparison.
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35         old <--- historic ---><--- current ---> now
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EXAMPLE

38       Take  the 12 last median values. Build the median out of the first 10
39       and the median from the other 2 values. Divide the results and decide
40       if it is bigger than 150 percent.
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42        Medratio(historic=>10,current=>2,comparator=>'>',percentage=>150);
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44        med(current)/med(historic) > 150/100
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46       This means the matcher will activate when the current latency median is
47       more than 1.5 times the historic latency median established over the
48       last 10 rounds of measurement.
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51       Copyright (c) 2006 by OETIKER+PARTNER AG. All rights reserved.
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SPONSORSHIP

54       The development of this matcher has been paied for by Virtela
55       Communications, <http://www.virtela.net/>.
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LICENSE

58       This program is free software; you can redistribute it and/or modify it
59       under the terms of the GNU General Public License as published by the
60       Free Software Foundation; either version 2 of the License, or (at your
61       option) any later version.
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63       This program is distributed in the hope that it will be useful, but
64       WITHOUT ANY WARRANTY; without even the implied warranty of
65       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
66       General Public License for more details.
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68       You should have received a copy of the GNU General Public License along
69       with this program; if not, write to the Free Software Foundation, Inc.,
70       675 Mass Ave, Cambridge, MA 02139, USA.
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AUTHOR

73       Tobias Oetiker <tobi@oetiker.ch>
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772.7.2                             2011.-.1:0:-l0i5b::Smokeping::matchers::Medratio(3)
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