[PLUG] Torrents of confusion

[Alan Olsen]

On 3/16/07, John Poelstra <poelcat at gmail.com> wrote:
>
> Jason Martin said the following on 03/15/2007 03:41 PM:
> > Probably the uploads, believe it or not.  TCP requires acknowledgments
> > to operate correctly and includes a backoff mechanism when it detects
> > congestion based on drops and retransmissions.  If your uploads are
> > sucking up all your upstream bandwidth (which is less than downstream
> > bandwidth for most broadband connections), then ACK messages will get
> > lost/dropped, and congestion control will kick in.
> >
> > Bittorrent is a great concept, but unless you have a router that does
> > quality of service traffic shaping, bittorrent uploads will definitely
> > kill your outbound traffic speeds, and by doing so will also kill your
> > download speeds.
>
> It sounds like a firewall or router problem.
>
> 1) What kind of router do you have?
> 2) Are you forwarding bittorrent ports to your host?
> 3) What type of firewall?
> 4) Which ISP?
> http://www.azureuswiki.com/index.php/Bad_ISPs


I have found two things that will cause the problems he is reporting.

1) if you are saturating the upload speed, download speed will drop on DSL.
Annoying, but true.  Seems to be just the way DSL works.

2) If your router has a small NAT buffer, it will get swamped and slow
down.  (BitTorrent tends to generate a huge number of connections.)
Sometimes a router update will fix this.  (If you have a Cisco home
router/firewall getting an update will fix this problem for the most part.)

Hope that helps.