Bottlenecks and link upgrades

Thu Aug 13 10:31:09 UTC 2020

On 13/Aug/20 12:23, Olav Kvittem via NANOG wrote:

> 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.
>

I'm confident everyone (even the cheapest CFO) knows the consequences of
congesting a link and choosing not to upgrade it.

Optical issues, dirty patch cords, faulty line cards, wrong
configurations, will almost likely lead to packet loss.  Link congestion
due to insufficient bandwidth will most certainly lead to packet loss.

It's great to monitor packet loss, latency, pps, e.t.c. But packet loss
at 10% link utilization is not a foreign occurrence. No amount of
bandwidth upgrades will fix that.

Mark.