Ted, [top posting]
RFC7084 does not have any support for internal routers. Futher: It might just be the way you describe the use cases, there seems to be a misconception about how routers work with regards to ND “advertisements”. ND is not a routing protocol. Hierarchical PD which you also allude to, was proposed, has limitations and was not standardized. That why HNCP was done. If you have a set of rfc7084 routers I believe you are left with manual configuration of prefixes and either manually configured static routing or RIP. Cheers Ole > On 4 Oct 2019, at 02:40, Ted Lemon <mel...@fugue.com> wrote: > > (If you got this as a Bcc, it’s because I am hoping you can contribute to > the discussion, but might not be on the mailing list to which I sent the > question, so please answer on-list if you are willing.) > > I’ve been involved in some discussions recently where the question has come > up: how good is support for RFC7084 in shipping routers? And what gaps > exist in RFC7084 that could cause problems? And in cases where RFC7084 > support either isn’t present, or isn’t useful because no IPv6 or because ISP > is delegating a /64, what things might work and what things might not, if we > want bidirectional reachability between two separate network links in the > home. > > So for example, suppose we have "CE Router," which supports RFC7084, > including prefix delegation. And we have "Internal Router" on that network > requests a delegation, and gets a prefix from the CE router. Presumably that > prefix is out of a larger prefix that CE Router got from the ISP. Great so > far. Let’s call the network on the southbound interface of Internal Router > “South Network”. Let’s call the network on its northbound interface, which is > also the network on CE router’s southbound interface, “North Network.” > > viz: > > ISP > | > CE Router > | > North Network > |-------------------------------+--------------+-----------------| > | | > Internal Router +---- Node A > | > South Network > |-----------+-------------------+--------------------------------| > | > Node B ---+ > > > If I want hosts on South Network to communicate with hosts on North Network, > what do I have to do? Should Internal Router publish an RA on its > northbound interface? What is the likelihood of that being filtered by the > network? If packets for South Network are forwarded through CE Router, will > it forward them on to Internal Router, forward them north, or drop them? > > Similarly, suppose we have a network where unfortunately PD Isn’t available > internally, but IPv6 is present on the northbound interface of the internal > node and southbound interface of the CE router. Suppose further that > Internal Router allocates itself a ULA prefix and advertises that as > reachable and on-link on its southbound interface, and as reachable but not > on-link on its northbound interface. Will that be blocked at layer 2 by CE > Router? I’m sort of assuming here that the CE router is managing the North > Network link, which is probably WiFi. > > Okay, now what if there’s no IPv6 support on CE Router or being provided by > CE router on North Network. Suppose Internal Router allocates a ULA and > allocates two /64s out of the ULA, one of which is advertised as reachable on > its northbound interface and on-link on its southbound interface, and a > second of which is advertised as on-link on its northbound interface and > reachable on its southbound interface. > > Fourth possibility: Node A is manually configured with an IPv6 address on a > prefix that Internal router is advertising as reachable on its southbound > interface, but which is not advertised on South Network because of filtering. > Node B has an address on a prefix that Internal Router is advertising as > on-link on its southbound interface. Node A has a static route configured > through Internal Router to the second prefix. Is there any reason to think > that traffic between Node A and Node B will be filtered at layer 2 by CE > Router, assuming that traffic on North Network is all going through CE Router? > > The goal here is to have bidirectional reachability between the two nodes on > IPv6 using either a global prefix or a ULA. The concern is that something > could prevent each of these cases from working. What I’m really curious > about is whether people have experience with doing communications of this > type using actual routers that ISPs are shipping. Is this “internal > network” scenario part of acceptance testing for these routers? Is this all > a big question mark? In principle this should all work, unless RA guard is > hyperactive in CE Router. But what about in practice? > > _______________________________________________ homenet mailing list homenet@ietf.org https://www.ietf.org/mailman/listinfo/homenet
