[Olsr-users] getting second best route from dikjstra's algorithm

[Teco Boot]

L2 traffic may help to get link metric feedback. OLSR uses multicast only, so it provides some signal quality (e.g. RSSI) and loss ratio stats (ETX) only. With user traffic (or probing), data rate and retransmit ratio is provided. With Minstrel, BestThroughput is provided (at transmitter side).

There is an experimental LQ NL80211 plugin available, using more than ETX. It is in src/linux/lq_plugin_ffeth_nl80211. I think the description is not in git. Bad. Here a copy Frank de Brabander posted in March 2012..

Teco

-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: OLSRD_LINUX_NL80211_EXTENSION.txt
URL: <http://lists.olsr.org/pipermail/olsr-users/attachments/20130614/e2de8086/attachment.txt>
-------------- next part --------------


Op 14 jun. 2013, om 10:37 heeft Vigneswaran R het volgende geschreven:

> On 06/14/2013 01:40 PM, Teco Boot wrote:
>> The trick is to converge to something that works well. L2 feedback may play an important role. Give the 2nd best route a chance and find out its L2 behaviour makes sense. Before the 2nd best route is taken, we must make sure there isn't a micro-loop.
> 
> Thank you for your points. I need to read about how to make use of L2 feedback. As of now, I am not able to think of how it can be implemented.
> 
> 
> Regards,
> Vignesh
> 
>> Teco
>> 
>> 
>> Op 14 jun. 2013, om 09:12 heeft Henning Rogge het volgende geschreven:
>> 
>>> On 06/14/2013 09:07 AM, Vigneswaran R wrote:
>>>>   +---- J --------- K -------+
>>>>  /                            \
>>>> A --- B --- C --- D --- E ---- F
>>>>        \                      /
>>>>         +-- M -- N -- O -- P-+
>>>> 
>>>> 
>>>> You're right. In the above scenario, A thinks that B,C,D,E,F is the
>>>> second best path. However, as far as B is concerned, M,N,O,P,F is the
>>>> 2nd best path. When we apply policy routing uniformly on all the routers
>>>> to use 2nd best path (for a particular traffic), traffic from A to F
>>>> will flow through B,M,N,O,P,F instead of B,C,D,E,F (and which remains
>>>> unused).
>>> It might be even worse. Think about a network like this:
>>> 
>>>  B---C---D
>>> / \ / \ / \
>>> A   X   X   H
>>> \ / \ / \ /
>>>  E---F---G
>>> 
>>> A might decide that A-B-C-D-H is the best path and A-E-F-G-H is the second best one.
>>> 
>>> But E decides that E-F-G-H is the best one and E-C-D-H is the second best one, pushing the traffic back onto the best path from A to H.
>>> 
>>> Henning Rogge
>>> -- 
>>> Diplom-Informatiker Henning Rogge , Fraunhofer-Institut für
>>> Kommunikation, Informationsverarbeitung und Ergonomie FKIE
>>> Kommunikationssysteme (KOM)
>>> Fraunhofer Straße 20, 53343 Wachtberg, Germany
>>> Telefon +49 228 9435-961,   Fax +49 228 9435 685
>>> mailto:(spam-protected) http://www.fkie.fraunhofer.de
>>> 
>>> -- 
>>> Olsr-users mailing list
>>> (spam-protected)
>>> https://lists.olsr.org/mailman/listinfo/olsr-users
>> 
> 
> 
> -- 
> Olsr-users mailing list
> (spam-protected)
> https://lists.olsr.org/mailman/listinfo/olsr-users