[Olsr-users] olsrd 0.6.6.1 (and earlier) ipv6 problems

[Henning Rogge]

Hi,

what kind of IPv6 addresses are assigned on bridges and interfaces
before and after you change the connectivity?

OLSRd use nearly the same codepaths for IPv4 and IPv6, so I expect
there is some "outside event" that triggers this behavior.

Henning Rogge

On Mon, Mar 24, 2014 at 11:44 PM, Russell Senior
<(spam-protected)> wrote:
>
> We have a network of around 60 nodes, running olsrd 0.6.6.1 (and
> earlier) in a hub and spoke topology, primarily over openvpn tunnels.
> The nodes are running recent trunk openwrt, the hub is a gentoo box.
> The nodes are a mixture of ar71xx, x86 and brcm47xx devices.  We
> provision ipv6 to the nodes through hurricane electric 6in4 tunnel to
> the well-connected hub machine, and then statically provising /64's to
> each of the nodes and let olsrd manage the routing tables.  We also
> run an ipv4 olsrd in parallel.
>
> Recently, we encountered our first node that had its own native ipv6
> upstream, which is preferable (as it takes the traffic load off our hub
> box).  To avoid routing confusion, we ultimately turned olsrd ipv6 off
> on that node.  Around the same time, we noticed that some of our nodes
> seemed to lose their ipv6 routing.  When I checked the routing tables
> on our hub machine (e.g. "ip -6 r"), all I saw were the local routes.
>
> I have a set of devices in a test-bed in my basement where I checkout
> newly built images where I have serial console.  My basement network
> has its own ipv6 network through a separate hurricane electric tunnel.
>
> I noticed that if I unplugged one of the devices in my test-bed, the
> hub machine gradually (over about 30-60 seconds) got all its ipv6
> routes back.  When I plugged in the test-device, boom, in 10-15
> seconds, the hub machine's ipv6 routing table collapsed again.  Unplug
> it, the routes come back.
>
> Meanwhile, the ipv4 routing table is steady as a rock.
>
> Eventually, I discover that an openwrt uci option ip6assign seems to
> be causing trouble, and I disable it.  Meanwhile the same image at
> another site does not appear to be causing any trouble, perhaps
> because it does not have an upstream ipv6 network?
>
> Then a few days ago, I look and notice that all (or virtually all) the
> ipv6 routes are gone from our hub machine again.  This time, I go to
> another of my test-bed devices and turn off the ipv6 olsrd there, and
> after 30-60 seconds the routes all come back again.  This time it is
> an x86 device (an alix2).
>
> Does this sound at all familiar?  Any suggestion where to start looking?
>
>
> --
> Russell Senior, President
> (spam-protected)
>
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