Re: Lossy cogent p2p experiences?

[Saku Ytti <saku () ytti fi>]

On Thu, 31 Aug 2023 at 23:56, Eric Kuhnke <eric.kuhnke () gmail com> wrote:

> The best working theory that several people I know in the neteng community have come up with is because Cogent does 
> not want to adversely impact all other customers on their router in some sites, where the site's upstreams and links 
> to neighboring POPs are implemented as something like 4 x 10 Gbps. In places where they have not upgraded that 
> specific router to a full 100 Gbps upstream. Moving large flows >2Gbps could result in flat topping a traffic chart 
> on just 1 of those 10Gbps circuits.

It is a very plausible theory, and everyone has this problem to a
lesser or greater degree. There was a time when edge interfaces were
much lower capacity than backbone interfaces, but I don't think that
time will ever come back. So this problem is systemic.
Luckily there is quite a reasonable solution to the problem, called
'adaptive load balancing', where software monitors balancing, and
biases the hash_result => egress_interface tables to improve balancing
when dealing with elephant flows.

-- 
  ++ytti