Re: Emulating ADSL bandwidth shaping

[Aria Stewart <aredridel () nbtsc org>]

On May 3, 2010, at 9:19 PM, Patrick Giagnocavo wrote:
> > - do ISPs typically use token bucket filters with large bursts to shape traffic?
> > - what kind of burst sizes and latencies/limits are typically used for
> > the filter?
>
> You will definitely have to account for latency.
>
> For emulating cable traffic, latencies (in the USA) will be about
> 60-80ms to typical sites.  Burst mode in my experience occurs only for
> about the first 15 seconds, then is throttled back (though not always;
> seems to depend on time of day).

And queues of 1 second at line rate are not uncommon, so if you load the link, things lag. 

> For DSL, I seem to recall latency being about 90-110ms (note, I haven't
> used DSL in many years).  Burst mode was generally not noticeable or
> available, that is, you got the same speed regardless of downloading a
> 1MB jpeg or a 640MB .iso  file.

Now more typically 40ms. And yeah, no bursts over normal line rate. Most turn down line rate for other plans, not shape.