From: Stephen Koran (skoran@austin.rr.com)
Date: Mon Feb 28 2005 - 13:30:37 GMT-3
So what apps measure at below 5 minutes?
Peyton Koran
> From: Andrew Lee Lissitz <alissitz@corvil.com>
> Reply-To: Andrew Lee Lissitz <alissitz@corvil.com>
> Date: Sat, 26 Feb 2005 08:30:26 -0500
> To: 'David Heaton' <David.Heaton@citec.com.au>, 'ali' <asayyed@atheer.net.sa>,
> 'ccielab' <ccielab@groupstudy.com>
> Subject: RE: ATM subinterface - and PCR/SCR :: Burst/CIR FrATM mapping?
>
> Good morning all, I can not comment on the ATM configs, and appreciate all
> the brilliant folk who post here, but concerning the monitoring BW question
> I can offer some guidance.
>
> When measuring BW utilization levels; always ensure that your measurements
> are the smallest times samples possible. These times range from 5 minutes
> (typical), 30 seconds (getting there), 15 seconds (better), and 5
> millisecond (very good) samples. The smaller the time sample the more
> accurate the reading.
>
> MRTG and SNMP polling every 5 minutes have always been extremely inaccurate
> about the utilization and nature of bursty traffic. Think about this;
>
> Voice, Citrix, market data apps, and basically every QoS application can be
> disrupted by the latency caused by congestion and other bursty apps.
>
> These periods of congestion last for milliseconds; how can sampling every 5
> minutes, (or large sample times) tell you this? The answer is that it can
> not, and any burst that is seen within these sample times is seen as a
> smooth rise or fall. There is no visibility into the nature of the traffic
> and any violation of QoS targets (jitter and delay, packet loss).
>
> When sampling BW and application traffic; the sample time needs to be as low
> as possible in order to show the true utilization levels and nature / affect
> of bursty traffic.
>
> HTH Ali Al-Sayyed / GS folk --> Kindest Regards all and have a great
> weekend,
>
> Andrew Lee Lissitz
> 908.303.4762
> www.corvil.com
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> David Heaton
> Sent: Saturday, February 26, 2005 6:34 AM
> To: ali; ccielab
> Subject: RE: ATM subinterface - and PCR/SCR :: Burst/CIR FrATM mapping?
>
> Using MRTG is one way to measure the util on a subif...
>
> Also, say you have a 128K frame access with 64K CIR
> that comes in via a FrATM link from your carrier,
> should you configure the PCR to be 128K and the SCR to be 64K
> on your ATM subinterface
>
> or, should you configure PCR 128 and SCR 128, and just
> the the carrier's ATM switch handle the flow/queuing?
> Any negative implications of doing this?
>
> Regards
> David
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> ali
> Sent: Monday, 14 February 2005 4:47 PM
> To: ccielab
> Subject: ATM subinterface
>
> Dear All
> How we can fin the current utilization bandwidth in the ATM sub
> interface,,
> did there is any way
>
> Ali Al-Sayyed
> CCIE #14265
>
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