Intel 4965 to Prism based AP Problems

Hi,

I'm looking for ideas to help troubleshoot a problem I'm having with
very poor wireless performance between a new laptop and my FreeBSD
4.10-Stable based AP.

Using my old laptop, there is no problem. That laptop uses the same
family of wireless card (just the miniPCI form.) The 802.11b wireless
cards are the prism 2.5 cards from Netgate, 2511CD PLUS EXT2, firmware
1.4.9

My new laptop has an Intel 4965. I can connect, and signal strength is
excellent. I do pass traffic, as I can ping to a vhost I has on the
Internet and do not see many drops. However, web traffic from sites
with large pages pretty much stops. In a different browser, 'Google'
(http://www.google.com) works just fine at this time.

If I plug in the ethernet cable, everything works fine, e.g. all the
sites I try to reach are really up.

If I run the old laptop using its wireless, it too works just fine.
If I connect to a neighbors (unprotected) store bought AP, the new
laptop works fine then. It also works just fine here in the office
(though its using .g for this post.)

The issue seems to be something between the laptop and my prisim card.
I'm looking for knobs to tweak.

Does anyone have any idea what to look at?


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On Thu, 7 Feb 2008 15:46:51 -0500, BostonDriver
<(E-Mail Removed)> wrote in
<(E-Mail Removed)>:

>I'm looking for ideas to help troubleshoot a problem I'm having with
>very poor wireless performance between a new laptop and my FreeBSD
>4.10-Stable based AP.
>
>Using my old laptop, there is no problem. That laptop uses the same
>family of wireless card (just the miniPCI form.) The 802.11b wireless
>cards are the prism 2.5 cards from Netgate, 2511CD PLUS EXT2, firmware
>1.4.9
>
>My new laptop has an Intel 4965. I can connect, and signal strength is
>excellent. I do pass traffic, as I can ping to a vhost I has on the
>Internet and do not see many drops. However, web traffic from sites
>with large pages pretty much stops. In a different browser, 'Google'
>(http://www.google.com) works just fine at this time.
>
>If I plug in the ethernet cable, everything works fine, e.g. all the
>sites I try to reach are really up.
>
>If I run the old laptop using its wireless, it too works just fine.
>If I connect to a neighbors (unprotected) store bought AP, the new
>laptop works fine then. It also works just fine here in the office
>(though its using .g for this post.)
>
>The issue seems to be something between the laptop and my prisim card.
>I'm looking for knobs to tweak.
>
>Does anyone have any idea what to look at?

Run a traceroute (tracert in WindowsSpeak) across the wireless link to
see if you're experiencing packet loss and where it might be occurring.

--
Best regards, FAQ for Wireless Internet: <http://Wireless.wikia.com>
John Navas FAQ for Wi-Fi: <http://wireless.wikia.com/wiki/Wi-Fi>
Wi-Fi How To: <http://wireless.wikia.com/wiki/Wi-Fi_HowTo>
Fixes to Wi-Fi Problems: <http://wireless.wikia.com/wiki/Wi-Fi_Fixes>

John Navas;191841 Wrote:
> On Thu, 7 Feb 2008 15:46:51 -0500, BostonDriver
> <(E-Mail Removed)> wrote in
> <(E-Mail Removed)>:
>
>
> >My new laptop has an Intel 4965. I can connect, and signal strength
> is
> >excellent. I do pass traffic, as I can ping to a vhost I has on the
> >Internet and do not see many drops.
>
> Run a traceroute (tracert in WindowsSpeak) across the wireless link to
> see if you're experiencing packet loss and where it might be
> occurring.
>
>

Traceroute to my AP (FreeBSD box) showed NO drops.

I did run ping the entire time (-n 10000000) I experienced the problem
and dropped just 1 or 2 datagrams. A few had larger delays (in ms
still), but still worked. I'm using the default timeout with XP.

While I saw the problem, I was ssh'ed into another system on the 'net
as well as my AP (FreeBSD system). Both were quite responsive.


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On Fri, 8 Feb 2008 11:10:50 -0500, BostonDriver
<(E-Mail Removed)> wrote in
<(E-Mail Removed)>:

>John Navas;191841 Wrote:
>> On Thu, 7 Feb 2008 15:46:51 -0500, BostonDriver
>> <(E-Mail Removed)> wrote in
>> <(E-Mail Removed)>:
>>
>> >My new laptop has an Intel 4965. I can connect, and signal strength
>> is
>> >excellent. I do pass traffic, as I can ping to a vhost I has on the
>> >Internet and do not see many drops.
>>
>> Run a traceroute (tracert in WindowsSpeak) across the wireless link to
>> see if you're experiencing packet loss and where it might be
>> occurring.
>
>Traceroute to my AP (FreeBSD box) showed NO drops.

Traceroute to the remote site on the Internet.
Post the exact output here.

--
Best regards, FAQ for Wireless Internet: <http://Wireless.wikia.com>
John Navas FAQ for Wi-Fi: <http://wireless.wikia.com/wiki/Wi-Fi>
Wi-Fi How To: <http://wireless.wikia.com/wiki/Wi-Fi_HowTo>
Fixes to Wi-Fi Problems: <http://wireless.wikia.com/wiki/Wi-Fi_Fixes>

C:\>tracert -d www.wirelessforums.org

Tracing route to www.wirelessforums.org [198.65.131.42]
over a maximum of 30 hops:

1 3 ms 1 ms 1 ms 172.16.6.1
2 * * * Request timed out.
3 * * * Request timed out.
4 * * * Request timed out.
5 * * * Request timed out.
6 * * * Request timed out.
7 * * * Request timed out.
8 * * * Request timed out.
9 * * * Request timed out.
10 * * * Request timed out.
11 * * * Request timed out.
12 * * * Request timed out.
13 * * * Request timed out.
14 * * * Request timed out.
15 * * * Request timed out.
16 * * * Request timed out.
17 * * * Request timed out.
18 * * * Request timed out.
19 ^C
C:\>


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BostonDriver <(E-Mail Removed)> hath
wroth:

>I do pass traffic, as I can ping to a vhost I has on the
>Internet and do not see many drops. However, web traffic from sites
>with large pages pretty much stops. In a different browser, 'Google'
>(http://www.google.com) works just fine at this time.
>
>If I plug in the ethernet cable, everything works fine, e.g. all the
>sites I try to reach are really up.

Let me guess. You have a PPPoE DSL internet connection and your
neighbor with the open access point has a cable modem? Checking
66.129.232.2 ... Groan. You're posting from work at Juniper? Oh
well.

My guess(tm) is that the difference is that PPPoE needs a slightly
smaller MTU. Try setting the MaxMTU on your new laptop to 1492
instead of the usual 1500.

See explanation at 14.25:
<http://www.lib.ru/LINUXGUIDE/freebsd_faq.html#MACOS-WIN98-PPPOE-FREEZE>

On your FreeBSD box, try:
ping -s 1472 -D your_ISP_gateway_IP_address
or
ping -s 1472 -M your_ISP_gateway_IP_address
1472 is actually a 1500 byte header due to the 28 byte header. (20
for the header and 8 for the PPPoE). If you're running PPPoE on your
DSL connection it should fail. Note that you're pinging your ISP, not
your local router. Now, decrease the MTU size to 1492 - 28 = 1464 and
try again. If my guess(tm) is correct, the 1472 will drop packets,
while the 1464 will work.

If you can find a Windoze box, you migth also try MTUroute.exe v2.1:
<http://www.elifulkerson.com/projects/mturoute.php>
If you can't find the Linux version or Windoze box, try the web based
version at:
<http://www.elifulkerson.com/projects/mtu-eyechart.php>

--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Sat, 9 Feb 2008 13:14:57 -0500, BostonDriver
<(E-Mail Removed)> wrote in
<(E-Mail Removed)>:

>C:\>tracert -d www.wirelessforums.org
>
>Tracing route to www.wirelessforums.org [198.65.131.42]
>over a maximum of 30 hops:
>
>1 3 ms 1 ms 1 ms 172.16.6.1
>2 * * * Request timed out.
>3 * * * Request timed out.
>4 * * * Request timed out.
>5 * * * Request timed out.
>6 * * * Request timed out.
>7 * * * Request timed out.
>8 * * * Request timed out.
>9 * * * Request timed out.
>etc.

What does a tracert to someplace you can get look like?

If it looks normal, then this would seem to be a routing problem.
Perhaps there is some blocking in place?

--
Best regards, FAQ for Wireless Internet: <http://Wireless.wikia.com>
John Navas FAQ for Wi-Fi: <http://wireless.wikia.com/wiki/Wi-Fi>
Wi-Fi How To: <http://wireless.wikia.com/wiki/Wi-Fi_HowTo>
Fixes to Wi-Fi Problems: <http://wireless.wikia.com/wiki/Wi-Fi_Fixes>

John Navas;192614 Wrote:
>
> What does a tracert to someplace you can get look like?
>
> If it looks normal, then this would seem to be a routing problem.
> Perhaps there is some blocking in place?
>
>

Traceroute isn't the best guide, as everything I tried (yet can get to)
show similar results (due to firewalls along the way), both wireless and
wired.

With the RJ45 plugged in, there are no problems to any destination.
Swap RJ45 with wireless for the last segment, I hit the problem I
described initially. I power up the old laptop (802.11b only), no
problems to anywhere.

In this case, all wireless cards are Netgate, 2511CD PLUS EXT2. Only
with the new laptop (and the Intel 4965 miniPCI a/b/g/n card) talking to
my FreeBSD AP is there an issue. That, or these 2511CD Plus ext2 cards
don't like talking to anything but themselves. Friends with new Dells
(similar, if not the same Intel wireless clients) all have the same
issue.


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Here is the card I use in HostAP mode on FreeBSD 4.10-Stable:

'Netgate' (http://www.netgate.com/product_info.php?products_id=191)

I have several of these setups, all in Soekris boxes except one, which
is a FreeBSD desktop used in cases such as this to debug problems
(wireless or otherwise).

All machines used as AP exhibit the same problem. Any time a wireless
client that isn't one of these 200mW 2511 CD PLUS EXT2 (either cardbus
or miniPCI) the problem exists.
Other 802.11b only clients (Orinoco) which I've tried in the past do
work just fine.


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BostonDriver <(E-Mail Removed)> hath
wroth:

>Traceroute isn't the best guide, as everything I tried (yet can get to)
>show similar results (due to firewalls along the way), both wireless and
>wired.

Did your news server miss my reply to your problem? See:
<http://groups.google.com/group/alt.internet.wireless/msg/148979cd200a761?hl=en>
--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558