Wouldn't it be better to measure the basic performance like packet drop rates and queue sizes ?


Those values should be a standard part of monitoring and data collection, but if they happen to MATTER or not in a given situation very much depends. 

The traffic profile traversing the link may be such that the observed drop % and buffer depths is acceptable for that traffic, and there is no need for further tuning or changes. In other scenarios it may not be, in which case either network or application adjustments are warranted. 

There is rarely a one sized fits all answer when it comes to these things. 
 

On Thu, Aug 13, 2020 at 6:25 AM Olav Kvittem via NANOG <nanog@nanog.org> wrote:


On 12.08.2020 09:31, Hank Nussbacher wrote:

At what point do commercial ISPs upgrade links in their backbone as well as peering and transit links that are congested?  At 80% capacity?  90%?  95%? 


Hi,


Wouldn't it be better to measure the basic performance like packet drop rates and queue sizes ?

These days live video is needed and these parameters are essential to the quality.

Queues are building up in milliseconds and people are averaging over minutes to estimate quality.


If you are measuring queue delay with high frequent one-way-delay measurements

you would then be able to advice better on what the consequences of a highly loaded link are.


We are running a research project on end-to-end quality and the enclosed image is yesterdays report on

queuesize(h_ddelay) in ms. It shows stats on delays between some peers.

I would have looked at the trends on the involved links to see if upgrade is necessary - 

421 ms  might be too much ig it happens often.


Best regards


  Olav Kvittem



Thanks,
Hank


Caveat: The views expressed above are solely my own and do not express the views or opinions of my employer