Mailinglist Archive: opensuse (3964 mails)
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Re: [SLE] OT: Calculating 95th Percentile
- From: Danny Sauer <suse-linux-e.suselists@xxxxxxxxxxxxxxxxxxxx>
- Date: Mon, 1 Nov 2004 11:48:04 -0600
- Message-id: <20041101174804.GI29415@xxxxxxxxxxxxxx>
Neil wrote regarding 'Re: [SLE] OT: Calculating 95th Percentile' on Mon, Nov 01 at 11:21:
> <snip>
>
> > > Our bandwidth is provided through a Summit48 switch / router. We get
> > > given 1MB/s bursting to 2MB/s.
> > >
> > > Is this achieved by configuring our port on the switch/router to have
> > > a max speed of 2MB/s ? then querying the switch/router every 5 minutes
> > > for the current throughput ?
> >
> > Perhaps I'm looking at this in an overly simplistic light, but don't
> > you just take the customer's bandwidth usage at samples of n minutes,
> > and then bill them for the usage point at which 95% of their usage is
> > below? In other words, make a chart, find the mean and standard
> > deviation, and add 2 standard deviations to the mean usage. That'll
> > get you the point at which 5% of the n-minute average samples are
> > above and 95% of the n-minute samples are below.
>
> Yes, this is correct. However, the thing I am interested in, is HOW
> is this actually done ? I.e, is the reading taken via SNMP off the
> router / switch ? Is this even possible. I dont know what can and
> cant be done with the high end routers / switch.
> Also, would the providor set the router / switch to allow up to 2MB/s
> ? or if not, what is restricting me to up to 2MB/s ?
You probably have a hard limit set at 2MB/s, and you're paying based
on 1MB/s usage, on the assumption that 95% of the time, you'll be
using less than 1MB/s. As far as getting the data, it varies. I
usually take the 1-minute average - get the number of bytes
transferred on a given port, wait a minute, get the number of bytes,
subtract, and that's bytes/minute. Divide by 60 and I've got 1-minute
average bytes/second. As far as what other providers do, I dunno.
Some likely use other time periods, but the idea's the same.
Either way, yes, you can get the reading via SNMP off of most managed
switches. I'm using iptables rules to log traffic at one site, and
I'm monitoring a switch with SNMP to keep track of some specific
workstations' usage. I'd think that your upstream provider is
probably doing the monitoring on their end, rather than with hardware
at the client site, but your router can probably also collect the
data.
--Danny
> <snip>
>
> > > Our bandwidth is provided through a Summit48 switch / router. We get
> > > given 1MB/s bursting to 2MB/s.
> > >
> > > Is this achieved by configuring our port on the switch/router to have
> > > a max speed of 2MB/s ? then querying the switch/router every 5 minutes
> > > for the current throughput ?
> >
> > Perhaps I'm looking at this in an overly simplistic light, but don't
> > you just take the customer's bandwidth usage at samples of n minutes,
> > and then bill them for the usage point at which 95% of their usage is
> > below? In other words, make a chart, find the mean and standard
> > deviation, and add 2 standard deviations to the mean usage. That'll
> > get you the point at which 5% of the n-minute average samples are
> > above and 95% of the n-minute samples are below.
>
> Yes, this is correct. However, the thing I am interested in, is HOW
> is this actually done ? I.e, is the reading taken via SNMP off the
> router / switch ? Is this even possible. I dont know what can and
> cant be done with the high end routers / switch.
> Also, would the providor set the router / switch to allow up to 2MB/s
> ? or if not, what is restricting me to up to 2MB/s ?
You probably have a hard limit set at 2MB/s, and you're paying based
on 1MB/s usage, on the assumption that 95% of the time, you'll be
using less than 1MB/s. As far as getting the data, it varies. I
usually take the 1-minute average - get the number of bytes
transferred on a given port, wait a minute, get the number of bytes,
subtract, and that's bytes/minute. Divide by 60 and I've got 1-minute
average bytes/second. As far as what other providers do, I dunno.
Some likely use other time periods, but the idea's the same.
Either way, yes, you can get the reading via SNMP off of most managed
switches. I'm using iptables rules to log traffic at one site, and
I'm monitoring a switch with SNMP to keep track of some specific
workstations' usage. I'd think that your upstream provider is
probably doing the monitoring on their end, rather than with hardware
at the client site, but your router can probably also collect the
data.
--Danny
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