Monitor mode and FCS

Bichot Guillaume Princeton BichotG
Wed Jan 15 12:43:27 PST 2003

Hi all,

We are working in monitor mode with Hostap-2002-10-12 and a linksys WPC11
pccard v3. We tried the set-up the card in order to receive the frame with a
wrong FCS (prism2_param wlan0 monitor_allow_fcserr 1).

We then use wlansniff. The packets belong to a downlink multicast RTP stream
forwarded by an access point (PC + hostap). We added in sniff the display of
the RTP sequence number.Being closed to the AP, all received frames are good
(status : 0000) and the RTP sequence number is sequential.

In order to create some wrong frames, we move away from the access point.
What we observed is that wlansniff display only good (status : 0000) frames
although our RTP sequence number was not anymore continuous.

We got the same result with different prism2x cards.

QUESTION : Does prism2_param wlan0 monitor_allow_fcserr works with any card
? Did we missed something in our configuration ?


Guillaume Bichot
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