Re: usb-Atmel - Ad0-Hoc - ZyAIR B-200 - Wifi Link OK, TCP/IP Link dead

Hi Jörg,

On Sat, 12 Jul 2003, Joerg Mertin wrote:

> ident: nic h/w: id=0x8026 1.0.0
> ident: pri f/w: id=0x15 1.1.0
> ident: sta f/w: id=0x1f 1.4.2
I was talking about the station fw - your 1.4.2 is fairly new.

> Regarding the IBSS - I figured it out. However - what I never saw anywhere
> mentioned - is how do the BSSI need to be set for the Add-Hoc mode to
> work, and how do the Mac-Addresses on the ofconfig call work.
>
> So - does the CELL-Entry has to look the same on both sides ? Or, in case
> of a WiFi Link, do the devices exchange their IBSS's ?

- BSS = basic service set = 2+ STA communicating
- IBSS = independent BSS = 2+ STA in ad-hoc mode
- ESS = extended service set = 1+ BSS connected by a distribtion
  system (DS). Each BSS contains one access point which acts as a
  STA (station) and connects the BSS to the DS.

Each BSS has its own BSSID = MAC address like id. The BSSID of an IBSS is
marked as temporary (bit 43 set to 1) and is randomly choosen on each
start of the IBSS. The BSSID of a BSS created by an access point usually
is its normal MAC address.

Furthermore each BSS has a service set ID (SSID) = a (normally
human readable) name of the IBSS/ESS.

iwconfig always calls the SSID "essid" and the BSSID "Cell:".

For ad-hoc mode, the "Cell:" entries must show the same addr. Be aware
that wlan-ng does not fully support the wireless extensions, i.e. using
iwconfig to obtain information may be broken. In my case iwconfig did not
show the correct "Cell:" id, I had to use their own tools
(wlanctl-ng/wlancfg ?).

In ad-hoc mode the first STA started usually scans for the given SSID and
if it cannot find a IBSS with it, starts its own, choosing a random BSSID
and using the configure channel. The second STA scans as well and find
this IBSS. If this fails for any reason, it starts a second IBSS and no
communication is possible.

> How about the Mac-Addresses of the "Virtual" network devices ? Are these
> also communicated to the remote side or not ?
What are "virtual" network devices?

> Could anyone here having a Working Add-Hoc config provide me the iwconfig
> and ifconfig output of their 2 Endpoints ? This would help me a lot.

no, sorry, have no running ad-hoc config here. But IMHO your setup looks
OK. I would:
- compare the Prism2's iwconfig output to the wlan tools' output
- try different start order
- run tcpdump in the background in case some data got corrupted
- check if ARP entries are received for the peer
- try broadcast pings

/Jörg