I have the same problem on an FSC Lifebook. The adapter is:

Intel Corporation PRO/Wireless 4965 AG or AGN [Kedron] Network Connection (rev 61)
and the driver is: iwlagn as well.

during these "freeze" times route hangs 

chris@laptop:~$ route
Kernel-IP-Routentabelle
Ziel            Router          Genmask         Flags Metric Ref    Use Iface
192.168.178.0   *               255.255.255.0   U     2      0        0 wlan0
link-local      *               255.255.0.0     U     1000   0        0 wlan0
------- here route hangs -------
default         fritz.fonwlan.b 0.0.0.0         UG    0      0        0 wlan0

I have attached my dmesg.

Furthermore the disconnects seem to be very regular (every 10 minutes) and i get the following in my syslog each time

Nov  4 22:30:01 laptop /USR/SBIN/CRON[8055]: (root) CMD ([ -x /usr/sbin/update-motd ] && /usr/sbin/update-motd 2>/dev/null)
Nov  4 22:33:02 laptop ntpd[7986]: synchronized to 130.149.17.21, stratum 1
Nov  4 22:39:35 laptop NetworkManager: <info>  (wlan0): supplicant connection state change: 7 -> 6 
Nov  4 22:39:35 laptop NetworkManager: <info>  (wlan0): supplicant connection state change: 6 -> 7 
Nov  4 22:40:01 laptop /USR/SBIN/CRON[8365]: (root) CMD ([ -x /usr/sbin/update-motd ] && /usr/sbin/update-motd 2>/dev/null)
Nov  4 22:48:04 laptop ntpd[7986]: synchronized to 130.149.17.8, stratum 1
Nov  4 22:49:35 laptop NetworkManager: <info>  (wlan0): supplicant connection state change: 7 -> 6 
Nov  4 22:49:35 laptop NetworkManager: <info>  (wlan0): supplicant connection state change: 6 -> 7 
Nov  4 22:50:01 laptop /USR/SBIN/CRON[8531]: (root) CMD ([ -x /usr/sbin/update-motd ] && /usr/sbin/update-motd 2>/dev/null)
Nov  4 22:51:46 laptop ntpd[7986]: synchronized to 130.149.17.21, stratum 1
Nov  4 22:55:29 laptop ntpd[7986]: synchronized to 130.149.17.8, stratum 1
Nov  4 22:59:35 laptop NetworkManager: <info>  (wlan0): supplicant connection state change: 7 -> 6 
Nov  4 22:59:35 laptop NetworkManager: <info>  (wlan0): supplicant connection state change: 6 -> 7 
Nov  4 23:00:01 laptop /USR/SBIN/CRON[8636]: (root) CMD ([ -x /usr/sbin/update-motd ] && /usr/sbin/update-motd 2>/dev/null)
Nov  4 23:03:36 laptop ntpd[7986]: synchronized to 130.149.17.21, stratum 1
Nov  4 23:09:35 laptop NetworkManager: <info>  (wlan0): supplicant connection state change: 7 -> 6 
Nov  4 23:09:35 laptop NetworkManager: <info>  (wlan0): supplicant connection state change: 6 -> 7 
Nov  4 23:10:01 laptop /USR/SBIN/CRON[8756]: (root) CMD ([ -x /usr/sbin/update-motd ] && /usr/sbin/update-motd 2>/dev/null)
Nov  4 23:16:58 laptop ntpd[7986]: synchronized to 130.149.17.8, stratum 1
Nov  4 23:17:01 laptop /USR/SBIN/CRON[8825]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Nov  4 23:19:35 laptop NetworkManager: <info>  (wlan0): supplicant connection state change: 7 -> 6 
Nov  4 23:19:35 laptop NetworkManager: <info>  (wlan0): supplicant connection state change: 6 -> 7 
Nov  4 23:20:01 laptop /USR/SBIN/CRON[8906]: (root) CMD ([ -x /usr/sbin/update-motd ] && /usr/sbin/update-motd 2>/dev/null)
Nov  4 23:29:35 laptop NetworkManager: <info>  (wlan0): supplicant connection state change: 7 -> 6 
Nov  4 23:29:35 laptop NetworkManager: <info>  (wlan0): supplicant connection state change: 6 -> 7 
Nov  4 23:30:01 laptop /USR/SBIN/CRON[9031]: (root) CMD ([ -x /usr/sbin/update-motd ] && /usr/sbin/update-motd 2>/dev/null)
Nov  4 23:33:38 laptop ntpd[7986]: synchronized to 130.149.17.21, stratum 1
Nov  4 23:39:35 laptop NetworkManager: <info>  (wlan0): supplicant connection state change: 7 -> 6 
Nov  4 23:39:35 laptop NetworkManager: <info>  (wlan0): supplicant connection state change: 6 -> 7 
Nov  4 23:40:02 laptop /USR/SBIN/CRON[9196]: (root) CMD ([ -x /usr/sbin/update-motd ] && /usr/sbin/update-motd 2>/dev/null)

If you need any further information I'd happily provide more.