So is AB full or Half duplex on the ethernet side....?

Scott


----- Original Message ----- 
From: "Lars Gaarden" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Friday, October 10, 2003 7:51 PM
Subject: Re: [smartBridges] Local traffic swamping with hub (MRTG)


> Blazen Wireless wrote:
> > Waykand,
> >
> > Just my 2 cents your also going to see problems with a cheap switch
unless
> > you can for sure get in and force it to 10 meg 1/2 duplex! the
Airbridges
> > don't play nice with switches that auto sense. I had to go out and buy a
12
> > port Cisco router that I could log into and set to the correct setting
and
> > if you go back there are many threads of people seeing problems with
packet
> > loss, slow throughput and many other problems all because an auto
sensing
> > D-link, Linkysys and many other cheap switches always sense the AB as 10
meg
> > FULL duplex.
>
> For whatever it is worth (2 cents?).
>
> It looks like any autoconfig ethernet device will config to 10Mbps
> full duplex
> if connected to an aP(P(O))/aB(O/T).
>
> In at least *some* configurations, this will give heavy (5-20%) packet
> loss
> in the upstream direction. Error counters on the ether and wireless side
> does not show this packet loss (lost/overrun/failed/aged/etc
> counters). If the
> device connected to the radio is set to 10Mbps half duplex, the problem
> disappears. Why? I have no idea. All I know is that I have to hard
> code the
> ethernet ports on my routers/firewalls (mainly rtl8139/a few intel
> 82558 eth
> chipset) to 10/hdx to avoid the problem.
>
> I asked my distributor to try to reproduce the problem in the lab, but
> they
> didn't find any problems with 10/fdx. So this is kind of a skeleton in the
> closet - some times 10/fdx works fine, some times it gives heavy
> packet loss.
>
> It could be a link layer problem - i.e., some ethernet chips don't
> work very
> well with the chip in the radios but only in fdx mode, it could be an
> ethernet
> driver problem, it could be a timing problem with running the radio
> eth port
> fdx when the wireless side work load is too high (the dual core atmel chip
> runs both the wireless and eth MACs). Pretty much impossible to debug
> unless
> you have debug/devel versions of the radio fw and eth driver on the other
> end of the cable and equipment to monitor the ethernet phys/link level
> signals.
>
> -- 
> LarsG
>
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