[Olsr-users] INFINITE cost in all links
Mon Jul 28 08:07:48 CEST 2014
On Fri, Jul 25, 2014 at 12:11 PM, Antonio Anselmi
> Hi all,
> I'm facing an odd problem that recurs randomly, without any user
> intervention, at different times on a single-gateway network.
> Suddenly, all the links of the gateway node have their NLQ values equal to
> zero and the respective LQ values greather than zero, so every link has an
> INFINITE cost -> olsrd route table is empty -> ip main route table is empty.
> Just because all NLQ values are zero, it seems that the nodes do not
> receive/hear olsrd packets from the gateway, but , at the same time, the
> gateway itself continues to receive and process packets sent by the other
> node (LQ values change in time).
> In this situation, I logged to the gateway node and run the command 'tcpdump
> -vv -ni wlan0-1 port 698' (wlan0-1 is the adhoc interface) to inspect the
> way olsrd was working.
> As supposed:
> 1) the gateway had stopped transmitting olsrd packets but continued to
> receive and process olsrd packets sent by the other nodes
> 2) olsrd route table and ip main route table were empty and the gateway does
> not ping any other node
> 3) the topology seen by the gateway have no node reachable
> 4) at layer2 the neighbors are all associated (iw dev wlan0-1 station dump)
> so adHoc beacons travel
> Stopping and restarting olsrd does not fix the stalemate as well as manually
> populating the ip main route table. Obviuosly, rebooting the node all goes
> right ...untill the next olsrd stale.
> I'm wondering:
> 1) Why all links go to INFINITE cost? (A loop caused by LQ mechanism?)
> 2) may be the case that the gateway try to transmit olsrd packets, but since
> its route table is empty, no packet reach the adHoc interface
> (loop inside the gteway) ?
> 3) since the TC-LQ packets sent by the nodes (and received by the gateway)
> do not show the gateway (NLQ = 0) why these packets reach the gateway? Nodes
> should have no route to the gateway since they do not hear it!
> 4) and... the all_INFINITE_costs situation (as well as the empty routing
> tables) is a "cause" or an "effect" ?
NLQ infinite most likely means that the other side cannot hear you,
but you can hear the other side.
Can you check on the gateway with the txtinfo command?
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