# Mismatch in interface utilization data

Hi Team,

I have created a report for Interface utilization. In which other teams have some doubts regarding populated data. Please see the below snapshot FYR.

Q:- The organization is asking, why the Average Transmit BPS Data + Average Receive BPS is not equal to Total Average BPS (Transmit+Receive).

Is there any justification for this mismatch in data?

• ImNishat,

When taking a look at this at first you thought it would be a simple sum total of the Transmit and Receive Averages but...

There is a THWACK Post from 10 Years ago that may help you with a justification for why the Transmit and Receive Averages are not the Sum Totals of the individual Transmit and Receive values assumed that they would be.

how is the average transmit and receive utilization calculated ? - Forum - Network Performance Monitor (NPM) - THWACK (solarwinds.com)

• That is not how it works

1. Total Average BPS (Transmit + Receive) = (((Average Transmit BPS) + (Average Receive BPS)) / 2 )

Which is correct

2. If I have to quote an example

- Say suppose you are polling this information for 25 mins where polling interval is 5 mins each so 5 data points

- Interface A -  Transmit BPS values - 2,2,2,2,2 - Hence the Average Transmit BPS = 10 (2+2+2+2+2) / 5 = Hence finally value is 2

- Interface A -  Receive BPS values - 3,3,3,3,3 - Hence the Average Receive BPS = 15 (3+3+3+3+3) / 5 = Hence finally value is 3

- Total Average BPS = (((Average Transmit BPS) + (Average Receive BPS)) / 2 ) = (2+3)/2 = Hence finally value is 2.5

- Now lets use the values directly rather than deriving it from (Average Transmit BPS) and (Average Receive BPS) - there are 10 data points in total for - Total Average BPS

- Total Average BPS = ((2+2+2+2+2) + (3+3+3+3+3)) / 10 -> 5 data points for Transmit and 5 data points for Receive - when you calculate this its 2.5

Its not sum of  (Average Transmit BPS) + (Average Receive BPS) rather is the Total Average from both Transmit and Receive (both included).

Hope this helps

• Good explanation.

I seen a similar equation on the 'stackoverflow' website.

•     That is a one the best explanations I have seen for this. The only thing I would add is that the words, not the math can be confusing. We tend to think that Total is the sum, not Overall Average or just as simply - average from both transmist and receive as it is in this case.

• Thank you for your explanation.

I will now try to communicate this to my other team members. I have made changes to the report by using the total received BPS instead of the average. The data I obtained aligns with the team's requirements. Please refer to the snapshot below. I have a couple of questions related to this report:

1. Which report (Average calculation or Total Calculation) provides us with the authentic data on actual consumption related to Interface utilization?

2. What is the difference in the meaning of Average received BPS or Total received BPS?

The use of this report is to evaluate our interface consumption, Based on this we can reduce or increase ILL or MPLS links to save cost.

• Hi

If possible, Please calculate this as mentioned below screenshot and guide me on how you calculate as per the above example.

Monthly Average Tr BPS = 4.84 MBPS

Monthly Average Rec BPS = 6.70 MBPS

How, is Monthly Total Average Tr+Rec BPS = 5.77 MBPS?

• (4.84 + 6.70) / 2 -> 11.54 / 2 -> Which is 5.77

Add 4.84 and 6.70 and then Divide it by 2

4.84+6.70 = 11.54

11.54/2 = 5.77 (Your final value)

• It actually depends, do you as well have NTA in your environment ?

• I have one doubt, Suppose in a week from Sunday to Saturday and utilization is 0,2,2,2,2,2,2 in this case it should be divided by six or seven to get a proper utilization report.