Cox clamping VPN traffic?

Sat Jan 26 07:21:08 UTC 2008

On Fri, 25 Jan 2008 20:30:20 -0500
"Ben Scott" <mailvortex at gmail.com> wrote:

> 
> On Jan 25, 2008 7:49 PM, Jim Popovitch <yahoo at jimpop.com> wrote:
> > I see the *exact* same problem with Comcast at home.  I get about 30
> > seconds of the 6.6Mbps provisioned rate then the drop kicks in and
> > down to 43kbps it goes.
> 
>   I suspect this is just bursting/clamping, as you suspect, but you
> may also want to investigate traffic shaping at your end.  I've found
> I get much better *receive* throughput if I limit my *transmit* rate
> to less than nominal maximum.  Presumably, this has to do with the
> fact that the feed is asymmetric; I can receive much faster than I can
> send, and so the send channel becomes congested and that impacts TCP
> ACK or other protocol control messages.
> 

For more details, 

"RFC3449 - TCP Performance Implications of Network Path Asymmetry"

http://tools.ietf.org/rfc/rfc3449.txt

Regards,
Mark. 

-- 

        "Sheep are slow and tasty, and therefore must remain constantly
         alert."
                                   - Bruce Schneier, "Beyond Fear"