[Olsr-users] How to make routes *very* sticky?

[Ben West]

I've been running a stress test on a mesh of 4 UBNT M5 radios with Openwrt
14 and olsrd 0.6.6.2 (the version still bundled with Barrier Breaker). The
3 repeater nodes are situated so that one provides an ideal route for the
other two back to the gateway node, with poorer wireless links between them
for redunancy.

The purpose of the test is to exercise the wifi driver to see if a
recurring lockup problem encountered with previous versions of Openwrt is
resolved (so far, yes, happily) , but I'd also been using the opportunity
to try out olsrd under heavier traffic load.

When I let all 3 repeater nodes run iterative curl downloads of a 500MB
file located upstream of the gateway node, i.e. to saturate all links (ping
times in the 100's of milliseconds), it looks like olsrd starts flapping
routes, breaking SSH sessions and other TCP streams.  This doesn't occur
with those nodes set to static routes and olsrd disabled.  I understand
this behavior is by design, as the poor ETX values from saturated links
will make the weaker, redundant links more appealing.  However, frequency
of flapping (~1x per hour), or so) is a bit disruptive.

My /etc/config/olsrd on all nodes is quoted below.  What is the best way
these days to enforce route stickiness?  I.e. try setting very low values
for SmartGatewaySpeed or is link hysteresis the more appropriate variable
to play with?

config olsrd

    option 'IpVersion' '4'
    option 'LinkQualityLevel' '2'
    option 'LinkQualityAlgorithm' 'etx_ffeth'
    option 'SmartGateway' 'yes'
    option 'SmartGatewayUseCount' '1'
    option 'Pollrate' '0.1'

config 'LoadPlugin'
    option 'library' 'olsrd_arprefresh.so.0.1'

config 'LoadPlugin'
    option 'library' 'olsrd_dyn_gw.so.0.5'
    option 'HNA' '0.0.0.0 0.0.0.0'

config 'LoadPlugin'
  option 'library' 'olsrd_nameservice.so.0.3'
  option 'sighup_pid_file' '/var/run/dnsmasq.pid'
  option 'suffix' '.mesh'

config 'LoadPlugin'
    option 'library' 'olsrd_txtinfo.so.0.1'
    option 'port'    '2006'
    option 'Accept' '127.0.0.1'

config 'Interface'
    list 'interface' 'wan'
    option 'Mode' 'ether'

config 'Interface'
    list 'interface' 'mesh'
    option 'Ip4Broadcast' '255.255.255.255'
     option 'Mode' 'mesh'

-- 
Ben West
http://gowasabi.net
(spam-protected)
314-246-9434
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