Subject: Re: Networking speed
To: Daniel Carosone <>
From: Bill Studenmund <>
List: tech-net
Date: 10/01/2004 10:28:00
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

On Fri, Oct 01, 2004 at 10:05:44AM +1000, Daniel Carosone wrote:
> On Thu, Sep 30, 2004 at 11:36:31PM +0100, Mark White wrote:
> > TSG recorded on NetBSD for MacOS->NetBSD transfers shows
> > approx 10ms bursts of traffic (a few dozen segments),
> > separated by gaps of a second or two.  Typical structure: at
> > the end of a burst I see segments 1-2-6-7, followed by a
> > second or so gap with no ACKs, then 3-4-5 out of order, and
> > resends of 6-7.  Then a few ms of good traffic, and repeat.
> This is definately some kind of packet loss; the out-of-order packets
> are ones that were not received the first time.  If you run the
> capture on OS/X, you should see them being sent.
> The pauses are Nagle's algorithm; the sender doing the congestion
> avoidance backoff referred to previously. You may also notice that the
> first few segments after a restart are more widely spaced.
> It's hard to say exactly without looking at it, but the lack of *any*
> ack's is a little confusing there. You should see at least one more
> re-ack when the out-of-order segment comes in. (just a little green
> tick on the line)

What have we changed with this stuff since 1.6? I have a MacOS X laptop=20
which opens tcp connections to a NetBSD box at work. Right after we=20
upgraded it to 2.0_BETA, I noticed tcp connections would stall. Downloads=
gave like 10% or 5% of the link capacity. Oh, this is a WAN connection.

> Does setting net.inet.tcp.delack_ticks=3D0 on netbsd help at all?

I'll see if we can try this.

Take care,


Content-Type: application/pgp-signature
Content-Disposition: inline

Version: GnuPG v1.2.3 (NetBSD)