* Juliusz Chroboczek > > BTW - this reminded me that I also noticed that after rebooting a > > router, another ULA prefix (*not* the one configured in OpenWrt on > > either router) also showed up and links were numbered using it, but it > > vanished again after a while. No idea where it came from. To be > > investigated! :-) > > See Section 6.5 of hncp-08: > > An HNCP router SHOULD create a ULA prefix if there is no other IPv6 > prefix with a preferred time greater than 0 in the network. > It MAY also do so, if there are other delegated IPv6 prefixes, but > none of which is locally generated (i.e., without any Prefix > Policy TLV) and has a preferred time greater than 0. However, it > MUST NOT do so otherwise. In case multiple locally generated ULA > prefixes are present, only the one published by the node with the > highest node identifier is kept among those with a preferred time > greater than 0 - if there is any. > > If memory serves, by default the OpenWRT implementation will create a > ULA even if there are GUA prefixes. If you reboot a router, the > election of the ULA might in principle cause transient ULAs to appear.
Right. What I'm experiencing is however the existence of *two* ULAs, one transient, and one permanent. See the screenshot below, taken after disconnecting the ISP-facing "WAN" interface: http://fud.no/openwrt-homenet-dual-ula.png The fd30:35c6:9ee8::/48 prefix configured under «IPv6 ULA-Prefix» near the bottom was automatically generated when OpenWrt was installed, and all active interfaces on that router (even the "WAN" one) are numbered with /64s from it at all times. My other Homenet router also has a auto-generated «IPv6 ULA-Prefix» setting which it numbers all of its interfaces from at all times. That means that during normal operation, hosts on a link between the two routers will have addresses from three prefixes: The ISP-delegated GUA, router 1's ULA, and router 2's ULA. R1 doesn't configure its local interfaces with addresses from R2's ULA or vice versa. fd98:d432:6004::/48 is the transient ULA here. When this is present, both R1 and R2 configure their local interfaces with it (so hosts connected to the R1-R2 link will at this point have acquired addresses from four distinct /64s: one ISP-delegated GUA, two permanent ULAs, and one transient ULA). What I am starting to suspect is that OpenWrt's «IPv6 ULA-Prefix» setting is orthogonal to the Homenet handling of the interfaces, and that in order to get the full/correct «Homenet experience» I should disable this setting on all my routers. It could perhaps be considered a bug that the «IPv6 ULA-Prefix» is used to number interfaces set to Homenet/HNCP mode in the first place? I'd appreciate it if you could confirm whether or not this is the case. Also, to answer you other question - yes, I do have a spare router lying around, and I do intend to try setting up wireless transit link. I'll let you know how it went, but it'll take a while before I get around to it, as I have to wait for a +3.3V UART to be delivered before I can get OpenWrt installed on it. Tore _______________________________________________ homenet mailing list [email protected] https://www.ietf.org/mailman/listinfo/homenet
