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

[Andreas Tønnesen]

Ok. But you should make sure that you only remove the GW in the cases
where you actually have a direct link to the interface.
Let us know how it works!

- Andreas

> 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
>> >> >
>> >> >
>> >> > _______________________________________________
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>> >> > https://www.olsr.org/mailman/listinfo/olsr-dev
>> >> >
>> >>
>> >>
>> >>
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