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..::lib::Smokeping::matchers::ExpLoss(3)                             SmokePing


NAME

       Smokeping::matchers::ExpLoss - exponential weighting matcher for packet
       loss with RMON-like thresholds


DESCRIPTION

       Match against exponential weighted average of last samples, thus new
       values are more valuable as old ones. Two thresholds - rising and
       falling - produce hysteresis loop like in RMON alert subsystem. If the
       average reaches the "rising" threshold, matcher go to the "match" state
       and hold It until the average drops under the "falling" threshold.

       Call the matcher with the following sequence:

        type = matcher
        pattern =  CheckLoss(hist => <hist>, rising=><rising> \
                            [,falling => <falling>] [,skip=><stat>] [,fast=><fast>])

       Arguments:
        hist    - number of samples to weight against; weight will be disposed
       with
                  exponetial decreasing manner from newest to oldest, so that
       the
                  oldest sample would have 1% significance;
        rising  - rising threshold for packet loss, 0-100%
        falling - falling threshold for packet loss, default is <rising>
        skip    - skip <skip> number of samples after startup before "fire"
       alerts.
        fast    - use <fast> samples for fast transition: if the values of
       last <fast>
                  samples more then <rising> - take "match" state, if less
       then
                  <falling> - take "no match" state.

       Note:
        If the actual history is less then <hist> value then this value is
       taken
        as the actual history.


COPYRIGHT

       Copyright (c) 2008 Veniamin Konoplev

       Developed in cooperation with EU EGEE project


LICENSE

       This program is free software; you can redistribute it and/or modify it
       under the terms of the GNU General Public License as published by the
       Free Software Foundation; either version 2 of the License, or (at your
       option) any later version.

       This program is distributed in the hope that it will be useful, but
       WITHOUT ANY WARRANTY; without even the implied warranty of
       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
       General Public License for more details.

       You should have received a copy of the GNU General Public License along
       with this program; if not, write to the Free Software Foundation, Inc.,
       675 Mass Ave, Cambridge, MA 02139, USA.


AUTHOR

       Veniamin Konoplev <vkonoplev@acm.org>

2.6.11                            2011-10-05
                                      ..::lib::Smokeping::matchers::ExpLoss(3)

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