[olsr-dev] Why are 1-hop routes with destination==gateway added

[Erik Tromp]

Yes, in fact the problem behind this is that these direct routes cause an interworking problem with OSPF by Quagga. You can read all
about it on this thread:

http://lists.quagga.net/pipermail/quagga-dev/2006-May/004121.html

Paul says that these direct, on-link routes are rather silly. I agree (to some extent) with Paul but maybe I have missed something.

Anyway, if you come up with something just let me know. For now I will try if quagga interworks with OLSR by patching away the
generation of direct, on-link routes in OLSR.



----- Original Message ----- 
From: "Andreas Tønnesen" <(spam-protected)>
To: "OLSR development" <(spam-protected)>
Sent: Friday, July 21, 2006 10:52 AM
Subject: Re: [olsr-dev] Why are 1-hop routes with destination==gateway added


>
> Hmm.. it's been a long time since I messed with that code :-)
> I think this was done for multi-homed nodes so that you would
> add the address of the interface you could reach as the GW and
> the IP of the other interface as dst.(I can't look at the code
> right now)
> Not a 100% sure though - and you are probably right that it is
> not needed for "direct" links. But would it pose a problem in
> any cases?
>
>
> - Andreas
>
> > Hi Andreas,
> >
> > Thanks for the quick response!
> >
> > I agree absolutely that, in general, the 1-hop neighbors should be added.
> > But why add the routes with gateway being the same as the
> > destination? Those destinations would have been reached anyway. Note: if
> > gateway equals destination, that negihbor is already on the
> > same subnet as we are.
> >
> > I removed the code adding specifically the 1-hop neighbors with gateway
> > being the same as destination, and (as expected) all worked
> > well. At least, in my humble test setup. Maybe you know of a test setup in
> > which it would go wrong?
> >
> > Erik
> >
> >
> > ----- Original Message -----
> > From: "Andreas Tønnesen" <(spam-protected)>
> > To: "OLSR development" <(spam-protected)>
> > Sent: Friday, July 21, 2006 9:50 AM
> > Subject: Re: [olsr-dev] Why are 1-hop routes with destination==gateway
> > added
> >
> >
> >>
> >> Hi Erik,
> >>
> >> All routers need not be on the same subnet in a MANET.
> >> Therefore it is absolutley nessecarry to add 1-hop neighbors to the
> >> routing table - or all other route going via this neighbor will also
> >> fail(if the negihbor is not on the same subnet as we are).
> >>
> >> - Andreas
> >>
> >> > Hi all,
> >> >
> >> > I have a small (maybe stupid) question.
> >> >
> >> > In the function olsr_add_routes_in_kernel, there is special code that
> >> adds
> >> > 1-hop routes to destinations, the gateway being the
> >> > destination itself. These routes are consequently added first (and
> >> deleted
> >> > last in the function olsr_delete_routes_from_kernel).
> >> >
> >> > My question is: why are these routes added at all? Since these are
> >> 1-hop
> >> > neighbors, these destinations would have been reached
> >> > anyway, because the network routes to all connected networks are
> >> already
> >> > in the routing table by default.
> >> >
> >> > Erik
> >> >
> >> >
> >> > _______________________________________________
> >> > olsr-dev mailing list
> >> > (spam-protected)
> >> > https://www.olsr.org/mailman/listinfo/olsr-dev
> >> >
> >>
> >>
> >>
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> >>
> >
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>
>
>
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