XO -> XO ping problem

[Dan Williams]

On Wed, 2007-06-27 at 22:53 -0700, Javier Cardona wrote:
> Dan,
> 
> Thanks for the detailed bug report.  Can the xo's ping each other over
> the mesh (i.e. assign an IP to the msh0 interface, and ping -I msh0)?

Will check when I get into work.

> What AP are you using?.  If the answer to the first question is yes

Linksys WRT54g HW v2, firmware v4.x-something.  I don't think it's
WDS-enabled at all, WDS doesn't show up anywhere in the interface, but I
could be wrong.

> and the AP being used does lazy-WDS (such as the WRT54G), then I have
> a good theory.  And the good news would be that the problem is solved
> by the new mesh data frame format that was released last week.  But
> let's wait until we try it in the office.

Yeah.

> Javier
> 
> 
> On 6/27/07, Dan Williams <dcbw at redhat.com> wrote:
> > Javier,
> >
> > We're observing an interesting problem here, replicated in at least 3
> > different locations (Waltham (me), Toronto (tamtam), Arlington
> > (dilinger)) on a bunch of different builds (406.x, 432, 451) with
> > different hardware (B1, B2, B3) and different firmware (5.220.10.p5,
> > 5.220.11.p5).  In all 3 locations, nothing is doing mesh networking at
> > all.
> >
> > The problem is that when connected in infrastructure mode, two XOs
> > cannot ping each _other_, but other normal laptops connected to the same
> > AP can ping each XO, and the XO can both ping the normal laptop and
> > external sites like google.
> >
> > For my investigation of this problem, I turned off NetworkManager
> > completely and booted up in runlevel 3.
> >
> > On both laptops I have, I did:
> >
> > chkconfig --level 345 NetworkManager off
> > chkconfig --level 345 dhcdbd off
> > chkconfig --level 345 network off
> > nano /etc/inittab (set runlevel 3 as default)
> > <reboot>
> > iwconfig eth0 essid foobar key <blah> mode managed
> > dhclient -1 eth0
> >
> > and then tried to ping each other XO from the other, and to ping google,
> > and to ping my ThinkPad T42.  The XOs always failed to ping each other,
> > but could both ping google and my T42.
> >
> > Digging further into the issue, I found via wireshark/ethereal on my
> > thinkpad that I can see the ARP request from XO1 -> XO2, but XO2 never
> > sends an ARP reply back (as seen from wireshark).  Turning on RX & TX
> > debugging in the driver on the XO2 shows the "SendSinglePacket succeeds"
> > message for (apparently) each ARP request XO2 receives, which I
> > interpret to mean that XO2 is actually trying to send the ARP reply, but
> > that the reply gets lost between the host_to_card() function and the
> > radio.  I can actually try to get the hexdump of the outgoing tx packets
> > if that would help.
> >
> > However, running tcpdump on both machines has interesting results.  The
> > pinging XO1 shows the pings in the dump, but the dump from the XO2 being
> > pinged shows only LLC frames, and no ICMP frames.  tcpdump isn't getting
> > any pings.  If you want the tcpdumps I can send you a link.
> >
> > Thoughts?  Can you try to replicate with, say, build 451 and debug the
> > issue as well?
> >
> > Thanks,
> > Dan
> >
> >
> >
> 
>