[GRLUG] NOT LINUX - broadband test

Adam Tauno Williams awilliam at whitemice.org
Sun Jun 27 22:22:05 UTC 2010


On Sun, 2010-06-27 at 11:13 -0400, Michael Mol wrote:
> As I mentioned earlier, if you have Comcast, you have SpeedBoost. If
> you have SpeedBoost, your transfer rate cap changes over the course of
> the transfer.  A 1MB file will have a different average transfer rate
> from a 1GB file, because that 1GB file will see a throughput drop
> somewhere early into the file.  What you *really* want to do is
> measure your throughput along 10s intervals over the course of a 2min
> transfer.  You should be able to find where SpeedBoost drops out
> there.

I know nothing about "SpeedBoost" [and, not being a Comcast customer,
have only a passing interest] - but this sounds a lot like CIR
[Committed Information Rate] with "bursting" to channel capacity.
Telecommunications companies have been selling that for ages [formerly
frame-relay, then ATM, now MPLS; at least once upon a time DSL & Cable
connections borrowed a lot of tech from the now essentially forgotten
ATM].

Do the Comcast routers permit any kind of indication of what they are
using to implement that?  Do they support any kind of traffic shaping -
allowing the end-user the ability to categorize some traffic as
discardable over other traffic?
-- 
Adam Tauno Williams <awilliam at whitemice.org> LPIC-1, Novell CLA
<http://www.whitemiceconsulting.com>
OpenGroupware, Cyrus IMAPd, Postfix, OpenLDAP, Samba


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