> >> Hmm... the current implementation of Babel requires IPv6 in the kernel. > > Let me explain a little more.
[...] > However, the current implementation only works over IPv6: while Babel will > route IPv4, IPv6 or both, the Babel messages will only be transported over > IPv6. (There are very good reasons to prefer IPv6 for transporting > protocol messages, most notably the fact that it makes it easier to > implement routing over unnumbered interfaces -- i.e. a router is able to > forward packets even before it's been assigned an address, or when only > some interfaces have an address. Additionally, the IPv6 multicast APIs are > somewhat more portable than the IPv4 ones.) > > I'd like to be clear that you don't need global IPv6 addresses, you don't > need router advertisements, you don't need global IPv6 connectivity. You > only need kernel support for IPv6, which is all that's needed to do > link-local multicast. Yes, that was my assumption. My point is: loading IPv6 support into the kernel is expensive - configuring some global IPv6 addresses is not. > > So on an openwrt router you need kmod_ipv6 installed ... we have such > > a setup (using 6to4 and radvd) > > Once again -- you don't need 6to4, you don't need radvd, you only need the > IPv6 kernel module. Sure, it's just the only way I have been able to verify that IPv6 support works in freifunkfirmware ... > > With olsrd and ipv6 and babel and openvpn or vtun and $monitor_tool > > running on the same mesh node we will most likely hit the RAM limit. > > FWIW, I'm happily running Babel + ahcpd + ntpd on 16MB OpenWRT machines > (MIPS). Ntpd is the largest of the three ;-) Once I have some proof of concept setup for freifunkfirmware I will be able to say more about that. > I don't know about vtun, but I know that Babel happily runs over SIT > tunnels, IP-IP tunnels, GRE tunnels and OpenVPN. For IP-IP, GRE and > OpenVPN, a small hack is needed. For IP-IP, a recent kernel is needed. > I have no idea about vtun. Ok. I was under the wrong assumption, that babel would need some ethernet type network interface. If we don't need OpenVPN then this should save quite some RAM... > I'm using OpenVPN and GRE in my network. Since vtun is insecure anyway, > I don't see any reason to prefer it to GRE. > > > OTOH if we need IPv6 support in the kernel anyway, then I don't see > > a reason not to do the whole experiment in IPv6 space - but perhaps > > I miss something. > > Don't worry about that -- it's a hybrid protocol. You can do both, or > either, or have some nodes doing IPv6 and other doing IPv4. By default, > Babel will route IPv6 on all interfaces, and route IPv4 on all interfaces > that have an IPv4 address. > > So as long as you get Babel running, you don't need to choose between IPv4 > and IPv6 -- you get whatever protocol you have configured addresses for. Sure, but since in Vienna olsr manages IPv4 and only IPv4 why not use babel together with IPv6? That way I don't need to worry about how to claim some IPv4 subnet for babel and I don't need to configure addresses on all nodes participating in the experiment: Just install babel + some special config file and it will route via IPv6 link local addresses by default. Just install some gobal addresses on nodes used for monitoring. Is that too simple? Harald _______________________________________________ Babel-users mailing list [email protected] http://lists.alioth.debian.org/mailman/listinfo/babel-users
