LLC protocol, ethereal and pcap libraries get along togheter?

["Claudio Lavecchia" <Claudio.Lavecchia () eurecom fr>]

Hello list,
 
Writing a packet dissector based on pcap libraries on Linux and using it to
sniff traffic going through a WLAN (dell truemobile 1150 with orinoco
driver) card I noticed a really strange behaviour. The card is set in
promiscous mode, and I used Ethereal to dump the sniffed packets in a
user-friendly way to further investigate what was going on.
What I observe is that the card sniffs packet that follow either the 802.3
(RFC 1042) encapsulation or the ethernet (RFC 894) encapsulation, which is
somewhat surprising, as I would expect that only one of those two
encapsulations (ethernet?) would be used. 
Furthermore, trough ethereal I could see that the "suspect" packets that are
encapsulated using the 802.3 encapsulation carry LLC protocol traffic and
seem to be originated, according to the source MAC address that I see in
ethereal, by another WLAN card of the same type. The odd thing is that the
device in which this card is plugged in is switched off at the moment I
execute the capture!
 
Can anyone turn the light on for me, please?
 
Claudio