Yura | 1 Mar 21:50 2009

Intel 5100, 5300 and 4965AGN clients can't connect in 802.11n mode


I'm using Asus WL500GPv1 router with AR5008/AR5416 wifi card and 2 additional
antennas running latest OpenWRT svn that includes ath9k driver from compat-wireless-2009-02-25.

Win XP client with Broadcomm BCM4321 card successfully connects at N rates up to 130mbps.

Other two laptops with Intel 5300 and 5100 cards can only connect in G mode.
Intel's wireless utility recognizes network as N mode. It shows "band: 802.11g, 802.11n"
in network properties and displays nice purple (n) icon. But connection speed is only
54mbps and 802.11g/a mode is displayed in "details" window.
I tried various ht_config parameters, different channels in 2.4 and 5ghz band,
all possible encryption modes and Intel driver settings.

I've noticed that this message appears in Intel wireless troubleshooter event log on each connection attempt:
"Security mismatch with 11n. 11n is not in operation"

Found some information about it from intel:
Client device's WiFi data rate will not exceed 54 Mbps when Wired Equivalent Privacy (WEP) or Temporal Key
Integrity Protocol (TKIP) encryption is configured.

The IEEE* 802.11n Draft prohibits using High Throughput with WEP or TKIP as the unicast cipher. If you use
these encryption methods (e.g. WEP, WPA-TKIP), your data rate will drop to 54 Mbps. The Intel®
WiMAX/WiFi Link 5350, Intel® WiMAX/WiFi Link 5150, Intel® WiFi Link 5300, Intel® WiFi Link 5100 and
Intel® Wireless WiFi Link 4965AGN client drivers connect using a legacy IEEE 802.11g connection rather
than failing to connect altogether, which complies with the IEEE 802.11n draft.
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