Bottlenecks and link upgrades

Sat Aug 15 08:47:45 UTC 2020

I've seen the weekly profiles of traffic sourced from caches for the major
global services (video, social media, search and general) for a specific
metro area.

For all services, the weekly profile is a repetition of the daily profile,
within +/- 20%.
That is: the weekly profile is obtained from the daily profile within +/-
20% of the average daily profile height.

Given this regularity, as suggested by Louie Lee, then it seems that growth
projections are meaningful.
That is, the weely profile data, seem to provide a sound empirical basis
for link upgrades.

Since I'm not an operator, my comments need to be sprinkled with a pinch of
salt :)

Cheers,

Etienne

On Sat, Aug 15, 2020 at 2:43 AM Louie Lee via NANOG <nanog at nanog.org> wrote:

> Beyond a pure percentage, you might want to account for the time it takes
> you stay below a certain threshold. If you want to target a certain link to
> keep your 95th percentile peaks below 70%, then first get an understanding
> of your traffic growth and try to project when you will reach that number.
> You have to decide whether you care about the occasional peak, or the
> consistent peak, or somewhere in between, like weekday vs weekends, etc.
> Now you know how much lead time you will have.
>
> Then consider how long it will take you to upgrade that link. If it's a
> matter of adding a couple of crossconnects, then you might just need a
> week. If you have to ship and install optics, modules, a card, then add
> another week. If you have to get a sales order signed by senior management,
> add another week. If you have to put it through legal and finance, add a
> month. (kidding) If you are doing your annual re-negotiation, well...good
> luck.
>
> It's always good to ask your circuit vendors what the lead times are, then
> double it and add 5.
>
> And sometimes, if you need a low latency connection, traffic utilization
> levels might not even be something you look at.
>
> Louie
> Peering Coordinator at a start-up ISP
>
>
> On Fri, Aug 14, 2020 at 4:13 PM Radu-Adrian Feurdean <
> nanog at radu-adrian.feurdean.net> wrote:
>
>> On Wed, Aug 12, 2020, at 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%?
>>
>> Some reflections about link capacity:
>> At 90% and over, you should panic.
>> Between 80% and 90% you should be (very) scared.
>> Between 70% and 80% you should be worried.
>> Between 60% and 70% you should  seriously consider speeding up the
>> upgrades that you effectively started at 50%, and started planning since
>> 40%.
>>
>> Of course, that differs from one ISP to another. Some only upgrade after
>> several months with at least 4 hours a day, every day (or almost) at over
>> 95%. Others deploy 10x expected capacity, and upgrade well before 40%.
>>
>

-- 
Ing. Etienne-Victor Depasquale
Assistant Lecturer
Department of Communications & Computer Engineering
Faculty of Information & Communication Technology
University of Malta
Web. https://www.um.edu.mt/profile/etiennedepasquale
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