[Olsr-users] Sticky gateway [was: olsr and streaming]

Sven-Ola Tuecke (spam-protected)
Mon Jan 19 16:07:59 CET 2009


a tunnel works well - at a first glance. It works, because the gateway-using 
node has the decision on what gateway it uses. What the nodes in-between 
think about this decision does not matter.

At the second glance, auto-tunnels have drawbacks:

a) difficult to firewall (at least for Gateway-Owner)

b) no more traceroute-debugging

c) auto-tunnels do not care about topo.

d) tends to be "manually optimized" (or so-to-speak: well optimized, if 
there's a regulary user, otherwise totally chaotic because it reflects a 
manual decision in the past)

e) leads to rotten default routes on each node (if that system resource is 
not used any more by third parties, people start to use default routes as 
solution for their half-understand routing problems. Which in turn makes 
default routes for forwarding unusable -> selecting the auto-tunnel route is 
a one-way-ticket for sure.

f) if we start auto-tunnels for 0/0 today, tomorrow we use them for /1, then 
/2 until we reach /32. I'm not sure about the implications.

But yes: it banns the loop-thread for the thesholded default routes and 
shifts decision from the protocol to the user.

// Sven-Ola

""L. Aaron Kaplan"" <(spam-protected)> schrieb im Newsbeitrag 
> First of all, I want to ask you to elaborate a bit on your claim.
> Can you give an example? Would be interesting.
> But so far I think you missed a point from the practical side here :)
> But I just saw that the others replied to it already.
> I also recently talked with Hannes - probably the clean way to do that
> (for NATed networks) is to have an automatic GRE tunnel (or some other
> tunnel) set up to the default gw which you want to "stick" to.
> But I guess everybody on the list is open to better proposals.
> a.
> summary & short answer from my perspective: "it works reasonably well
> in all networks in practice which I have encountered for now"
> -- 
> Olsr-users mailing list
> (spam-protected)
> http://lists.olsr.org/mailman/listinfo/olsr-users 

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