WDS speed issues revisited

Dave dave
Wed Apr 9 01:54:33 PDT 2003


'iwconfig wlan0 rate 11M fixed'

does not fix the TX rate. In fact once I issue that command for one side of
a WDS link which is currently at 11Mbps, the rate drops to 2Mbps.

I think I understand Jean's comment that the RX is controlled by the
opposite ends TX...but if the opposite ends TX is fixed to 11M then in
theory wouldn't this ends RX receive at 11M....minus the overhead, retrys,
errors, birds, planes..

I am at least confident that the displayed speed via iwconfig wlan0 on each
side of the link in WDS/Repeater mode is accurate as I perform data
transfers each way and it is right at the displayed speed.

I also am pretty comfortable that the initial WDS issue was related to my FW
mishap...I now have radios seperated by 2.5 miles and initially get an
11Mbps link...which quickly turns into a 1Mbps link as soon as data starts
moving...but that is probably related to fade margin or something because I
do not have perfect LOS...but still it would be great to have it fixed at
11Mbps and deal with fade and errors and loss as a seperate issue.

Again thanks for all your help!


> I think I may have found the issue and resolution...and it bums me out
> because I have been bit by this before...;(
> Some of my cards have STA FW of 1.5.6 and the rest have 1.4.9 or 1.3.6. I
> never worried much about permanantly flashing them up to 1.5.6 because my
> startup scripts do a ram upload at boot time....and I CAN talk WDS 4-ADDR
> then...so I thought all was good.
> On a hunch I used two cards that had 1.5.6 and did no ram upload on
> bootup...once the first ping packet from AP1 hit AP2 both WDS speeds
> up from 2Mbps to 11Mbps and stayed there even after packets stopped.
> I then tried a 1.5.6 card with no ram upload and a 1.4.9 card ram uploaded
> to 1.5.6 on bootup...sure enough I could talk WDS 4-ADDR but the 1.4.9
> was stuck at 2Mbps while the 1.5.6 card jumped to 11Mbps right away.
> This has bitten me before when trying to get WDS-4 working
> I should have remembered the issue.
> Jouni (or anyone), what is the correct procedure to reinitialize a card
> after a ram upload in order to take advantage of the features of the newer
> FW. I have tried tonight to issue an "iwpriv wlan0 reset 2" thinking that
> might do it but to no avail.
> I have flashed 1.5.6 into two of my 1.4.9 cards and am not doing a ram
> upload on bootup...and for the past 30 minutes I see 11Mbps on both
> boxes....I will try some heavy data transfers and see if anything happens
> but it is my guess that all will be ok.
> Thanks again for all your assistance Jouni...you have been extremely
> helpful....and patient. I will let you know how fixed rate control works
> soon as I get a couple radios a few miles apart where conditions should
> cause normal rate control.
> Thanks!
> -Dave
> > On Tue, Apr 08, 2003 at 07:23:52PM -0700, Dave wrote:
> >
> > > I physically set two hostap boxes on my workbench about 5 feet apart,
> > > installed two brand new radios, rebuilt hostap from the latest release
> and
> > > installed/configured...no luck on a successful, stable 11Mbps WDS
> >
> > Which transmit rates are being used with the CVS version (i.e., the one
> > that is supposed to fix Repeater mode rate control)? Do you see
> > different rates being used or only one? I would be interested in seeing
> > /proc/net/hostap/wlan0/<other end hwaddr> statistics for the link.
> >
> > If the other end does not ACK frames for some reason, rate control
> > algorithm will most certainly drop the rate. If that is the case, I
> > would like to find out why the ACKs are not sent.
> >
> > If you want to test hardcoding rate control, that should also be fixed
> > now (althought complete untested ;-) for Repeater mode. 'iwconfig wlan0
> > rate 11M fixed' should in theory allow only rate 11M being selected for
> > TX rate.
> >
> > --
> > Jouni Malinen                                            PGP id EFC895FA
> > _______________________________________________
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> > HostAP at shmoo.com
> > http://lists.shmoo.com/mailman/listinfo/hostap
> >
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