On Oct 6, 2006, at 3:21 PM, Peter Jones wrote:
On Fri, 2006-10-06 at 00:56 -0700, Scott Lamb wrote:
3) Khaled said this: "You don't reconfigure your network card
every time
you travel." This is because the laptop gets its regulatory domain
information from the Access Point via 802.11d. You can't legally
operate
Access Points in different regulatory domains without adjustment.
Now, I
have absolutely no idea what this means for mesh networking...
Huh? That doesn't quite follow. You can't know if it's legal to
associate with an AP during scanning, or even know what channels
you're
allowed to scan, until you've selected your regulatory domain.
When a scan is initiated, you already have a list of channels
that's ok
to talk on, and it's determined by a static table in the driver,
indexed
by the geo code read from the firmware on the machine -- typically the
firmware of the WiFi device itself.
See, for example, wlan_scan_create_channel_list() in
libertas/wlan_scan.c, or ipw_request_scan() (and its helper
ipw_add_scan_channels() ) in ipw2200.c .
It's certainly possible to hack things up to use a user-settable geo,
but that is not what drivers currently do.
I think my wording is at fault here. I'm talking about the way a
modern general consumer laptop is supposed to work. I have not looked
at any of the code you're describing. What I heard (which seems
consistent with a quick sanity check against wikipedia's 802.11d
entry) is that the AP sends out the regulatory domain as part of the
beacon, so laptops can read this information before transmitting
anything back.
--
Scott Lamb <http://www.slamb.org/>
_______________________________________________
Devel mailing list
[email protected]
http://mailman.laptop.org/mailman/listinfo/devel
