Emulating ADSL bandwidth shaping

Marshall Eubanks tme at americafree.tv
Tue May 4 07:27:21 CDT 2010


On May 4, 2010, at 8:02 AM, Dave Hart wrote:

> On Tue, May 4, 2010 at 08:54 UTC, Raymond Dijkxhoorn wrote, quoting  
> Patrick:
>>> For emulating cable traffic, latencies (in the USA) will be about
>>> 60-80ms to typical sites.
> [...]
>>> For DSL, I seem to recall latency being about 90-110ms (note, I  
>>> haven't
>>> used DSL in many years).
> [...]
>> The latency i have here on my DSL is ~ 16-22 ms. So its much lower,  
>> factor
>> 4...
>
> Either you're looking only at the loop contribution, or you're in the
> SF bay area and nearly every "typical site" is available locally.
> Here in the relatively backwater Seattle suburbs, unless it's served
> by Microsoft or a content distribution network, there are substantial
> latencies to typical sites.
>

I am not sure what the point is in mixing in speed of light latency.  
If your "typical sites" are, say,
Indian cricket blogs, you will typically have a high latency from the  
US. What does that tell
you about your DSL or Cable system, except that it is somewhat removed  
from India ?

Regards
Marshall


> To make it concrete I used Windows ICMP tracert against a few sites
> from both cable and DSL in the Seattle suburbs.  First from a
> consumer-grade cable offering:
>
> http://pastebin.com/TGc6xsHk
>
> Then from a business-class telco DSL (complete with more than 1 static
> IP, someone tie me down lest my soul escape my body from sheer joy!):
>
> http://pastebin.com/DMrsiUQf
>
> Note I made no attempt to ensure I was tracing to the same numeric IP
> address from both, and the tests were simultaneous.
>
> Cheers,
> Dave Hart
>
> P.S.  A special flip of the bird to those IWFs who filter all ICMP at
> the edge and break path MTU detection.
>
>





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