[Olsr-dev] Network topology if there is a node get down?

Agung Septiadi (spam-protected)
Mon Jun 16 08:06:10 CEST 2008

I have OLSR network which has topology like this.
node A <-> node B <-> node C <-> node D (gateway) <------> internet
Node A, node B, node C, and node D using Ubuntu 8,04
I accessed video streaming to our Youtube-like website in our intranet
and Yahoo messenger with Pidgin from Node A to Internet via Node B,
Node C and Node D (gateway)

Then, I turned Node E (WindowsXP) on which is located between Node A and Node D. Network Topology was becoming like this
node A <-> node B <-> node C <-> node D <------> internet
node A <-----------> node E <--------> node D <------> internet

I  captured ping activity from node A to node D. The result is showed below (Node D is and Node E is

64 bytes from icmp_seq=211 ttl=62 time=3.69 ms
64 bytes from icmp_seq=212 ttl=62 time=5.11 ms
64 bytes from icmp_seq=213 ttl=62 time=4.21 ms
64 bytes from icmp_seq=214 ttl=62 time=4.55 ms
From icmp_seq=215 Redirect Host(New nexthop:
64 bytes from icmp_seq=215 ttl=63 time=5.25 ms
From icmp_seq=216 Redirect Host(New nexthop:
64 bytes from icmp_seq=216 ttl=63 time=6.17 ms
From icmp_seq=217 Redirect Host(New nexthop:
64 bytes from icmp_seq=217 ttl=63 time=4.74 ms
From icmp_seq=218 Redirect Host(New nexthop:
64 bytes from icmp_seq=218 ttl=63 time=4.37 ms

Sequence no.214 was still routed via node B and node C
On Sequence no 215, packet routing had been diverted via node D
Packet routing from node A to node D had been diverted (from node A
-> node B -> node C ->node D -> internet To node A ->
node E -> node D -> internet) smoothly
Buffering process on streaming and Pidgin was not disconnected at all.

If I turned Node E down, First, there was ping loss (I think ping loss is normal when there is node who has down, CMIIW)
Here is the ping activity when I had turned node E down

From icmp_seq=383 Redirect Host(New nexthop:
64 bytes from icmp_seq=383 ttl=63 time=192 ms
From icmp_seq=384 Redirect Host(New nexthop:
64 bytes from icmp_seq=384 ttl=63 time=129 ms
From icmp_seq=385 Redirect Host(New nexthop:
64 bytes from icmp_seq=385 ttl=63 time=103 ms
From icmp_seq=386 Redirect Host(New nexthop:
64 bytes from icmp_seq=386 ttl=63 time=89.8 ms
64 bytes from icmp_seq=506 ttl=62 time=5.26 ms
64 bytes from icmp_seq=507 ttl=62 time=5.10 ms
64 bytes from icmp_seq=508 ttl=62 time=6.65 ms
64 bytes from icmp_seq=509 ttl=62 time=4.77 ms

Sequence no.386 was still using node B and node C's link
are ping losses from sequence 387 to seq no. 505 (there are about 119
packet losses) (FYI, I set HelloValidityTime to 120 s on every node)
On this state, buffering process was stopped, and Pidgin was still connected but could not send any messages to everybody

After about 120 secs, Ping routing had been been diverted via node B and node C again, (Start from icmp_seq=506)
But, buffering processing on the video streaming completely stopped and Pidgin was disconnected.

all applications was disconnected after there is a node get down,
whereas all applications was still connecting if there are node get up
offering better link?
Was OLSR doing something wrong?

Here are my olsrd.conf on every node without commenting

DebugLevel    0
Interface "ath0" 
    HelloInterval        6.0
    HelloValidityTime        120.0
    TcInterval            3.0
    TcValidityTime        300.0
    MidInterval            15.0
    MidValidityTime        300.0
    HnaInterval            10.0
    HnaValidityTime        120.0
LinkQualityFishEye 1
LinkQualityDijkstraLimit 3 3.0
IpVersion    4
ClearScreen     yes
AllowNoInt    yes
Willingness        7
     MaxConnections  0
UseHysteresis    no
LinkQualityLevel    2
LinkQualityWinSize    100
Pollrate    0.1
TcRedundancy    2
MprCoverage    5

On Gateway (Node D), I have added HNA configuration

*Sorry for my previous mail which is sent by gmail. I wasn't receive my previous own email from [olsrd-dev] mailist as a broadcasted mail. I thought there is something wrong with my gmail. I'm sorry for your inconvenience*

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