[CUWiN-Dev] notes on TDV

[Matt Isaacs]

Here's what I've been running to test the node's connections:

netstat -rn -f inet | awk '/^169\.254\./ { print $1; }' | xargs -n 1 ping -c
100 -n | tee pings.txt

I then use this to extract the parts I'm interested in:

cat pings.txt | grep "Statistics\|packets\|round-trip" > sum.txt

If anyone sees a problem with this or knows of a better way, please let me
know.

I don't ping the 10.0 addresses as its impossible to get an accurate measure
due to route fluctations.

On 10/30/06, Matt Isaacs <isaacsm at cuwireless.net> wrote:
>
> The tpscale isn't going to work as well as we had hoped, at least not at
> 3.  The node appears to see nothing but itself at 3.  If we slide up to a
> scale of 2, we see more stuff but poorly.  We get ~75& packet failure rate
> to nodes that are directly next to it.  (I've been testing from a gateway.)
> I'm trying it now with 1.  What I've seen suggests ~50% packet failure rate
> to neighboring nodes.  No scaling yeilds about a 30% failure rate to
> neighboring nodes.
>
> I'll try turning off IP6 and see what that does for us.
>
> On 10/30/06, David Young <dyoung at pobox.com> wrote:
> >
> > On Sun, Oct 29, 2006 at 09:38:39PM -0600, David Young wrote:
> > > Some routers at TDV are spending about 50% of their CPU time in the
> > > operating system, leaving very little CPU headroom for forwarding,
> > HSLS,
> > > etc.  I believe we owe the system overhead to the density of the
> > network;
> > > every node can hear every other, so every node is bombarded by HSLS
> > > packets.  There are a few things we can try to get the CPU usage down:
> > >
> > >         1 Turn off IPv6 (easily halves the number of packets).
> >
> > Turned off in the TDV build.
> >
> > >         2 Scale transmit power (sysctl -w hw.ath0.tpscale=4) to
> > control
> > >           nodal degree and interference.
> >
> > I set tpscale to 3 on the TDV build.  I hope that isn't too much.
> >
> > >         3 Figure out how to adjust receive sensitivity to filter
> > >           out transmissions from distant nodes.
> >
> > Looks to me like the HAL does not provide an API for that.
> >
> > > Matt and I noticed that the diversity sysctl is turning back on
> > > (hw.ath0.diversity = 0 -> 1) when the ath0 is brought up.  I.e., we
> > > need to put '!/sbin/sysctl -w hw.$int.diversity=0' at the bottom of
> > > ifconfig.backhaul.tmpl.  I don't know if this is making any practical
> > > difference, since we have forced the interfaces to use just one
> > antenna
> > > for transmit and receive, and those settings are not reset when we
> > bring
> > > the interface up.
> >
> > Done.
> >
> > > Matt tells me that dhcpselect is not working right on gateways.  If
> > the
> > > DHCP server is not available when the node boots, dhcpselect may or
> > > may not detect an Internet connection when the DHCP server starts.
> > > Sounds like a regression in dhcpselect.
> >
> > I haven't investigated this, yet.
> >
> > Dave
> >
> > --
> > David Young             OJC Technologies
> > dyoung at ojctech.com      Urbana, IL * (217) 278-3933
> > _______________________________________________
> > CU-Wireless-Dev mailing list
> > CU-Wireless-Dev at lists.cuwireless.net
> > http://lists.chambana.net/cgi-bin/listinfo/cu-wireless-dev
> >
>
>
>
> --
> Matthew Isaacs
>
> CUWiN Network Engineer




-- 
Matthew Isaacs

CUWiN Network Engineer
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