Subject: Re: tinkering with wi interfaces (Prism 2.5)
To: Wojciech Puchar <firstname.lastname@example.org>
From: Jeff Rizzo <email@example.com>
Date: 01/21/2004 12:54:21
On Wed, Jan 21, 2004 at 10:13:08AM +0100, Wojciech Puchar wrote:
> > I've read over the wi(4), ifconfig(8), ifmedia(4), and wiconfig(8)
> > man pages, and I'm trying to find how to hardwire certain
> > things in the new world order where most settings are done in
> > ifconfig rather than wiconfig. (To give you a hint on the last
> > time I played around seriously with this stuff, it was about
> > the time the "wavelan" page on the netbsd website was originally written, and
> > *it* references 1.4G).
> general good ideas with WiFi links are:
> 1) if stations aren't moving frequently, so there are same conditions most
> of time, turn off speed autonegotiation and set maximum speed that works
There's the rub; I haven't figured out how to stop autonegotiation from
happening at some level; I thought that setting it with "ifconfig wi0
media DS11" would do it, but it would appear that some (if not all)
frames are sent at lower speeds anyway.
> 2) all antennas have to see each other, or "hidden node" problem produces
> lots of collision and retransmition
Yup, I'm aware of that. Only two nodes, anyway.
> 3) ad-hoc mode is generally fastest.
> i'm working on my own PtP and PtMP mode program that bypasses part of the
> 802.11 protocol sending everything as broadcasts (no ACKing this case with
> adhoc mode) and doing all air access control and retranmitions by myself.
> mostly deciding exactly when each node transmits data, instead of "try and
> maybe you are lucky" method in standard WiFi.
> it's mostly for long distance outdoor network, but could be usable indoors
> too. of course unix only.
Which is exactly what I'm doing. :) The nodes are about 3 or 4 km apart.
> this eliminates most common problem - high packet loss where there are
> lots of connections and full speed transmisions. this case "try end error"
> algorithm of transmission have low chance of sending data without making
I'd certainly be interested in looking at anything you're doing in this
Jeff Rizzo http://boogers.sf.ca.us/~riz