Subject: Re: ifconfig for wireless LAN
To: None <>
From: Jason R Thorpe <>
List: tech-net
Date: 03/14/2000 08:50:42
On Tue, Mar 07, 2000 at 10:37:27PM +0900, Atsushi Onoe wrote:

 > I'd like to propose the changes of ifconfig media/mediaopt for IEEE802.11
 > wireless LAN as follows:
 > 	media		{ infrastructure | adhoc }
 > 	mediaopt	[ create-ibss | no-bssid ] [ wep ] [ power-mgmt ]
 > Comparing with the current usages:
 > 	media		{ FH1 | FH2 | DS1 | DS2 | DS5 | DS11 }
 > 	mediaopt	[ adhoc ]
 > I think it's not so good at the following points.
 > 	1. "FH" and "DS" cannot be set at all.  It just show the type of
 > 	   PHY chip on the card, and printed at attaching the interface
 > 	   would be enough.

Hm.  That's true.  I guess there aren't really any cards that do both :-)

However, it is nice to be able to explicitly set the speed...  Although,
I guess this really isn't practically useful, is it...

 > 	2. Bit rate is not necessarily specified for most cases.
 > 	   Both for infrastructure mode and ad-hoc (IBSS) mode,
 > 	   spec says that the PHY with multirate support MUST use
 > 	   basic rate for multicast/broadcast and control frames,
 > 	   and MUST NOT transmit at a higher rate without prior knowledge
 > 	   of destination's supported rate, which are shown by beacon
 > 	   frames or association requests.
 > 	   Though only WaveLAN ad-hoc mode may need of fixed rate,
 > 	   auto rate select apparently works on WaveLAN ad-hoc mode.
 > 	3. The infrastructure mode and the ad-hoc mode are clearly different
 > 	   and cannot interoperable each other.  So they cannot be "media
 > 	   options" but mutually exclusive "media types".

Hm, that's true.

 > And there are some more options to be defined for wireless LAN.
 > 	create-ibss	Create its own IBSS and announce it when it fails
 > 			to find or join existing IBSS.
 > 			Only valid for the adhoc media type.
 > 			Note that isolated two node with this option
 > 			cannot talk to eath other even if they come closer
 > 			again.
 > 	no-bssid	Do not use bssid nor beacons at all.  It is just
 > 			same as adhoc mode of WaveLAN (wi(4)).
 > 			Only valid for the adhoc media type.

I assume that no-bssid would be the default for adhoc always?  How is this
different from any other adhoc mode, or is adhoc on the `wi' not interoperable
with the adhoc mode on e.g. `ray'?  (ignoring the FH/DS issue...)

 > 	wep		Enables WEP (Wired Equivalent Privacy).  It requires
 > 			WEP encryption to communicate others.
 > 	power-mgmt	Enables power management capability.  Only available
 > 			for infrastructure media type and it requires
 > 			additional support by access points.
 > Possibly more to be defined somewhere:
 > 	desired ESSID	currently can be specified by the "nwid" parameter of
 > 			ifconfig(8).  Empty string ('') means wildcard
 > 			ESSID which allow to connect any access points.
 > 	created ESSID	used for "create-ibss".  It may be the same string
 > 			with desired ESSID but it should not be empty.
 > 	WEP key		used for "wep" encryption/decryption.
 > 	channel/pattern	used for "create-ibss" to determine the radio
 > 			frequency (DS) or hopping pattern (FH) to be used
 > 			to create IBSS.  Also used for "no-bssid".

All of these could be handled with ifconfig, I think.  "created ESSID"
could be "cessid".

 > Though I'm not quite sure whether these parameters should be specified
 > by ifconfig, I don't hope there are so many XXXconfig commands...

I think they should be.  Seems silly to have a separate program to do
all this stuff when it can be reasonably handled by ifconfig(8).

Ignore the fact that ifconfig(8) is a pile of junk inside :-)

 > Any comments?

Only the ones above :-)  I'd like to hear comments from Chris Hopps
and Bill Sommerfeld on this issue, tho.

        -- Jason R. Thorpe <>