From: Pavel Roskin <proski@gnu.org>
To: Bcm43xx-dev@lists.berlios.de, linux-wireless@vger.kernel.org
Subject: Capture of unsuccessful ARP exchange
Date: Mon, 19 Feb 2007 20:31:25 -0500 [thread overview]
Message-ID: <1171935085.8133.42.camel@dv> (raw)
[-- Attachment #1: Type: text/plain, Size: 1859 bytes --]
Hello!
As I wrote before, bcm43xx_d80211 connects quickly to an 802.11g AP only
if it doesn't support OFDM modes (bcm43xx_g_ratetable_size changed from
12 to 4). Actually, association is not a problem, but no data goes
through for several minutes.
I'm attaching a capture file of an unsuccessful APR exchange following
the association.
The AP is current MadWifi, MAC address 00:0F:B5:35:73:D8. The STA is
current bcm43xx_d80211 from mb branch, PCIe 4312, MAC address
00:19:7D:21:7B:50. The capture is done by another system running
Wireshark 0.99.5 and current MadWifi in monitor mode.
AP broadcasts a beacon announcing that it supports rates from 1 to
54Mbps. The flags indicate short preamble, spectrum management and
short slot time.
STA broadcasts an ARP request at 36Mbps. QoS field requests normal ACK.
STA receives ACK at 24Mbps.
STA broadcasts another ARP request, this time at 1Mbps. It's a non-QoS
data frame. However, the flags indicate that it's a frame from DS not
to DS, unlike the previous ARP request that got that part correctly!
AP rends APR reply at 5.5Mbps. QoS field requests normal ACK, which
never arrives.
AP sends another such frame with retry bit set, followed by 6 more
frames at 1Mbps. QoS field requests normal ACK, which never arrives.
STA broadcasts an ARP request at 36Mbps. To-DS is set correctly. Retry
bit is set. QoS field requests normal ACK.
STA receives ACK at 24Mbps.
STA broadcasts an ARP request at 24Mbps. To-DS is set correctly. Retry
bit is set. QoS field requests normal ACK.
Following seems wrong to me:
1) STA sends some packets with From-DS instead of To-DS. I've seen more
than one such packet, and they are always sent at 1Mbps.
2) STA doesn't send ACK to frames specifically requesting it (if I
understand the Wireshark interpretation correctly).
--
Regards,
Pavel Roskin
[-- Attachment #2: 80211g-arp --]
[-- Type: application/octet-stream, Size: 3305 bytes --]
next reply other threads:[~2007-02-20 1:31 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-20 1:31 Pavel Roskin [this message]
2007-02-20 1:58 ` Capture of unsuccessful ARP exchange Jouni Malinen
2007-02-20 2:28 ` Pavel Roskin
2007-02-20 8:23 ` Johannes Berg
2007-02-20 10:04 ` Michael Buesch
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