Reliability & Load

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Oct 31st, 2008
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If we see the interface status of Cisco router, it will show reliability(255/255) & load(1/255).

What is the formula behind this?

And, Is there any reason to take measurement 255?

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Overall Rating: 4.5 (2 ratings)
Joseph W. Doherty Fri, 10/31/2008 - 04:20
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I don't recall seeing documentation on why "255" but likely this is because a byte binary integer can range from 0..255. To convert to a %, just divide the first number by the second, e.g. load(45/255) equals about 17.6%.

pkaretnikov Fri, 10/31/2008 - 07:24
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Reliability is calculated using the following formula:

reliability = number of errors / number of total frames


Referring to Load-interval

The length of time, in seconds, used to calculate the average load on the interface. Valid values range from 30 to 600 seconds, in multiples of 30 seconds. The default is 300 seconds (5 minutes).

Modify the default to shorten the length of time over which load averages are computed. You can do this if you want load computations to be more reactive to short bursts of traffic.

Load data is gathered every 5 seconds. This data is used to compute load statistics, including input/output rate in bits and packets per second, load, and reliability. Load data is computed using a weighted-average calculation in which recent load data has more weight in the computation than older load data.



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