[Olsr-dev] Multipath routing in OLSRD

Hannes Gredler (spam-protected)
Tue Apr 28 11:07:18 CEST 2009

extending the infrastructure and add a strawman (=ECMP routes only)
is perhaps a good idea anyway - later on we can decide what fancy algorithms we can
out on for determining path diversity, loopfreeness  for non ECMP paths etc.


Markus Kittenberger wrote:
> I would also suggest you share your ideas about multipath stategies here,..
> because if you just send data to all neighbours that would not send the 
> packets directly back to you, you just multiply the chances to get 
> routing loops on one of your path,..
> i mean, if you take the risk of having more problems, you should have a 
> very good stategy to really gain better significant improves,..
> i mean if 1 or 2 hops later all you packets will go again through the 
> same link, its for sure not worth the risk/effort.
> and if your plan is to send packets on every node to "every" posibble 
> route, you may use quite long, bad routes, and suffer with enourmous 
> packet loss/reordering problems (if you do not gurantee that "same" 
> traffic takes (mostly) same route)
> i don`t want to say, multipath will not work, neither do i know your 
> plans, but first step imho is to solve well some theoretical issues, 
> before starting to hack this feature in,..
> regards Markus
> On Tue, Apr 28, 2009 at 9:58 AM, Henning Rogge <(spam-protected) 
> <mailto:(spam-protected)>> wrote:
>     Am Tuesday 28 April 2009 00:33:36 schrieb Adam Nowak:
>      > Hello,
>      > I'm new to this list, and to all the olsr stuff too. Sorry, if
>     I'm asking
>      > about well known issues. I'm interested in implementing multipath
>      > extension to OLSRd. At first, I'd like to add some alternative
>     routes to
>      > the same destination (route entries which has the same
>     destination but
>      > other next-hops). As I've noticed in the code, there is the entry
>      > "rt_best" which is responsible for selecting best route. I don't
>      > understand, how OLSRd interacts with system routing table in
>      > olsr_update_rib_routes() function, can you help me work it out or
>     give
>      > some advices?
>      > Any help would be appreciated!
>     The main problem you have to solve is how to force your packages to
>     stay on
>     the "secondary" route. You cannot do this "hop by hop" because the
>     next hop
>     will just send your packages to the shortest route again.
>     For efficient multipath you need some "distance" (2 hops or more)
>     between the
>     two routes to prevent collisions between the two paths.
>     Henning
>     *************************************************
>     Diplom Informatiker Henning Rogge
>     Forschungsgesellschaft für
>     Angewandte Naturwissenschaften e. V. (FGAN)
>     Neuenahrer Str. 20, 53343 Wachtberg, Germany
>     Tel.: 0049 (0)228 9435-961
>     Fax: 0049 (0)228 9435-685
>     E-Mail: (spam-protected) <mailto:(spam-protected)>
>     Web: www.fgan.de <http://www.fgan.de>
>     ************************************************
>     Sitz der Gesellschaft: Bonn
>     Registergericht: Amtsgericht Bonn VR 2530
>     Vorstand: Prof. Dr. rer. nat. Maurus Tacke (komm. Vors.), Prof. Dr.-Ing.
>     Joachim Ender (Stellv.)
>     --
>     Olsr-dev mailing list
>     (spam-protected) <mailto:(spam-protected)>
>     http://lists.olsr.org/mailman/listinfo/olsr-dev

More information about the Olsr-dev mailing list