Emulating ADSL bandwidth shaping

Dave Hart davehart at gmail.com
Tue May 4 07:02:39 CDT 2010


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.

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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