[Olsr-dev] Meshing over VPNs

[Markus Kittenberger]

On Tue, Oct 4, 2011 at 1:46 PM, Benny Baumann <(spam-protected)> wrote:

> Hi Markus,
>
> Am 04.10.2011 11:23, schrieb Markus Kittenberger:
> > On Tue, Oct 4, 2011 at 2:00 AM, Benny Baumann <(spam-protected)
> > <mailto:(spam-protected)>> wrote:
> >
> >     Hi guys,
> >     (well, several of our routers died regularly from the routing tables
> >     being too large).
> >
> > hmm why are the routing tables getting too large?
> When doing FIBMetric "correct" the RT not only holds one route per
>
use flat! *G

> destination, but one route per distance and host. So sometimes we get up
> to 2 or 3 routes per host.
>
(which is (or at least sounds like) a bug,..)

> > olsrd would anyways just create as many routes as there are targets
> > (hosts)
> > (regardless of the topology)
> Yes, but using the plugin we can somehow channel these routes somewhat
> and make some of them appear as "INFINITE" so OLSR knows the host is
> there, but doesn't try to route directly to it. And that's what wwe
> wanted to get.
>
knowing a host/link is there, also needs memory (just less than having it in
topology and creating a route for it)

> > but the with such a huge layer2 broadcast domain, olsrds network
> > topology gets bigger (and therefore the olsrd memeory consumption)
> > furthermore the number of olsrd messages might get very unfunny)
> Problems arose for us at only about 10-15 nodes in the Tinc network. A
> live graph can be seen at http://graph.chemnitz.freifunk.net/ffc.svg The
> plugin doesn't run on all the (pink) nodes yet, but on those which have
> it you'll see no gray lines (which are the virtual connections Tinc
> introduces). The pink lines are direct Tinc connections. BTW: This
> drastically reduces the size of TC messages which are much more common
>
sure the tc messages are a bigger traffic/bandwidth problem as the hellos.
(but they can be fragmented into multiple messages)

so as hellos can not fragmented they limit your maximum number of
neighbours,..
but for ipv4 its more than 100 neighbours that fit into one packet,..

than the HELLO messages (I sent the stats for our network previously on
> the list). For all the Tinc nodes we use HELLO intervals of sometimes up
> to 5 minutes thus there's not much concern regarding HELLO messages;
>
ok, fine. but as said above its not only about bandwidth,..

> more regarding TC. Currently we have 4.5KB/s TC down and 0.5KB/s TC up;
> which makes using the network on Edge links feasable (not quite nice,
> but feasable).
>
this sound like a very small network,..  (but i don not know your tc timings
on all the nodes)
(but how does tinc broadcast the messages, sending duplicated packets to all
other nodes in the tinc cloud?)

would this create 450KB/sec for a 100 nodes tinc cloud??

But as far as I understand it OLSR doesn't include INFINITE/non-SYMM
> links in the HELLO-message.

this is true for Tcs but not for Hellos.

> And as we are dropping default quality down
> to INFINITE those get removed.


Markus
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