[Olsr-dev] Bug in timing out stale TC entries
Erik Tromp
(spam-protected)
Sun Feb 24 15:57:51 CET 2008
Hi all,
I think there is a bug which as introduced in version 0.5.4 and is still present in 0.5.5 . The bug was not present in 0.5.3 and
earlier (those good old times... :-).
The problem lies in that some stale (old) TC entries take extremely long (5-10 minutes) before they are cleaned up, and sometimes
are not cleaned up at all.
I have a small test network of 4 nodes. A picture of it is available at:
http://home.tiscali.nl/levab001/OLSR-BMF-testnetwork.pdf
In the beginning, all is well. Node 10.0.4.3 has the following
state:
--- 14:26:43.83 ---------------------------------------------------- LINKS
IP address hyst LQ lost total NLQ ETX
10.0.6.6 0.000 1.000 0 5 1.000 1.00
10.0.6.5 0.000 1.000 0 5 1.000 1.00
10.0.5.5 0.000 1.000 0 5 1.000 1.00
10.0.6.4 0.000 1.000 0 5 1.000 1.00
--- 14:26:43.02831232 ----------------------- TWO-HOP NEIGHBORS
IP addr (2-hop) IP addr (1-hop) TLQ
10.0.8.6 10.0.4.4 1.000
10.0.8.5 1.000
10.0.8.5 10.0.4.4 1.000
10.0.8.6 1.000
10.0.4.4 10.0.8.6 1.000
10.0.8.5 1.000
--- 14:26:43.83 ------------------------------------------------- TOPOLOGY
Source IP addr Dest IP addr LQ ILQ ETX
10.0.4.3 10.0.4.4 1.000 1.000 1.00
10.0.4.3 10.0.8.5 1.000 1.000 1.00
10.0.4.3 10.0.8.6 1.000 1.000 1.00
10.0.4.4 10.0.4.3 1.000 1.000 1.00
10.0.4.4 10.0.8.5 1.000 1.000 1.00
10.0.4.4 10.0.8.6 1.000 1.000 1.00
10.0.8.5 10.0.4.3 1.000 1.000 1.00
10.0.8.5 10.0.4.4 1.000 1.000 1.00
10.0.8.5 10.0.8.6 1.000 1.000 1.00
10.0.8.6 10.0.4.3 1.000 1.000 1.00
10.0.8.6 10.0.4.4 1.000 1.000 1.00
10.0.8.6 10.0.8.5 1.000 1.000 1.00
This information is consistent with that on node 10.0.8.5:
--- 14:23:14.96 ---------------------------------------------------- LINKS
IP address hyst LQ lost total NLQ ETX
10.0.5.3 0.000 1.000 0 5 1.000 1.00
10.0.6.3 0.000 1.000 0 5 1.000 1.00
10.0.6.6 0.000 1.000 0 5 1.000 1.00
10.0.2.4 0.000 1.000 0 5 1.000 1.00
10.0.6.4 0.000 1.000 0 5 1.000 1.00
--- 14:23:14.02969528 ----------------------- TWO-HOP NEIGHBORS
IP addr (2-hop) IP addr (1-hop) TLQ
10.0.8.6 10.0.4.3 1.000
10.0.4.4 1.000
10.0.4.4 10.0.4.3 1.000
10.0.8.6 1.000
10.0.4.3 10.0.8.6 1.000
10.0.4.4 1.000
--- 14:23:14.96 ------------------------------------------------- TOPOLOGY
Source IP addr Dest IP addr LQ ILQ ETX
10.0.4.3 10.0.4.4 1.000 1.000 1.00
10.0.4.3 10.0.8.5 1.000 1.000 1.00
10.0.4.3 10.0.8.6 1.000 1.000 1.00
10.0.4.4 10.0.4.3 1.000 1.000 1.00
10.0.4.4 10.0.8.5 1.000 1.000 1.00
10.0.4.4 10.0.8.6 1.000 1.000 1.00
10.0.8.5 10.0.4.3 1.000 1.000 1.00
10.0.8.5 10.0.4.4 1.000 1.000 1.00
10.0.8.5 10.0.8.6 1.000 1.000 1.00
10.0.8.6 10.0.4.3 1.000 1.000 1.00
10.0.8.6 10.0.4.4 1.000 1.000 1.00
10.0.8.6 10.0.8.5 1.000 1.000 1.00
Now I shutdown the interface from node 10.0.4.3 into the 10.0.6.x network This is visible on 10.0.4.3 :
--- 14:49:29.03 ---------------------------------------------------- LINKS
IP address hyst LQ lost total NLQ ETX
10.0.5.5 0.000 1.000 0 5 1.000 1.00
--- 14:49:29.0230914 ----------------------- TWO-HOP NEIGHBORS
IP addr (2-hop) IP addr (1-hop) TLQ
10.0.8.6 10.0.8.5 1.000
10.0.4.4 10.0.8.5 1.000
--- 14:49:29.03 ------------------------------------------------- TOPOLOGY
Source IP addr Dest IP addr LQ ILQ ETX
10.0.4.3 10.0.8.5 1.000 1.000 1.00
10.0.4.4 10.0.4.3 1.000 0.596 1.68
10.0.4.4 10.0.8.5 1.000 1.000 1.00
10.0.4.4 10.0.8.6 1.000 1.000 1.00
10.0.8.5 10.0.4.3 1.000 1.000 1.00
10.0.8.5 10.0.4.4 1.000 1.000 1.00
10.0.8.5 10.0.8.6 1.000 1.000 1.00
10.0.8.6 10.0.4.4 1.000 1.000 1.00
10.0.8.6 10.0.8.5 1.000 1.000 1.00
The first stale TC entry is visible here:
10.0.4.4 10.0.4.3 1.000 0.596 1.68
which does not seem to get removed.
Also on node 10.0.8.5 we can see two TC entries that don't go away:
--- 14:45:23.91 ---------------------------------------------------- LINKS
IP address hyst LQ lost total NLQ ETX
10.0.5.3 0.000 1.000 0 5 1.000 1.00
10.0.6.6 0.000 1.000 0 5 1.000 1.00
10.0.2.4 0.000 1.000 0 5 1.000 1.00
10.0.6.4 0.000 1.000 0 5 1.000 1.00
--- 14:45:23.02915630 ----------------------- TWO-HOP NEIGHBORS
IP addr (2-hop) IP addr (1-hop) TLQ
10.0.8.6 10.0.4.4 1.000
10.0.4.4 10.0.8.6 1.000
--- 14:45:23.91 ------------------------------------------------- TOPOLOGY
Source IP addr Dest IP addr LQ ILQ ETX
10.0.4.3 10.0.8.5 1.000 1.000 1.00
10.0.4.4 10.0.4.3 1.000 0.596 1.68
10.0.4.4 10.0.8.5 1.000 1.000 1.00
10.0.4.4 10.0.8.6 1.000 1.000 1.00
10.0.8.5 10.0.4.3 1.000 1.000 1.00
10.0.8.5 10.0.4.4 1.000 1.000 1.00
10.0.8.5 10.0.8.6 1.000 1.000 1.00
10.0.8.6 10.0.4.3 1.000 0.800 1.25
10.0.8.6 10.0.4.4 1.000 1.000 1.00
10.0.8.6 10.0.8.5 1.000 1.000 1.00
>From the above list, the following TC entries should have been romoved:
10.0.4.4 10.0.4.3 1.000 0.596 1.68
10.0.8.6 10.0.4.3 1.000 0.800 1.25
On node 10.0.4.4 the following stale entry can be seen:
10.0.8.6 10.0.4.3 1.000 0.800 1.25
On node there 10.0.8.6 are even four stale entries:
10.0.4.4 10.0.8.5 0.400 1.000 2.50
10.0.4.4 10.0.8.6 0.400 1.000 2.50
10.0.8.5 10.0.4.4 1.000 0.596 1.68
10.0.8.6 10.0.4.4 0.400 1.000 2.50
Which of the stale entries remain in place seems to be rather random: when the experiment is repeated, there may be other entries
that are not cleaned up.
One of the results is that BMF does work function properly, since it relies on the information in the TC database.
Regards,
Erik
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