The document currently says: > 8. Mobile IP > > The Mobile IPv6 [RFC3775] specification defines requirements for the > following types of nodes: > > - mobile nodes > - correspondent nodes with support for route optimization > - home agents > - all IPv6 routers > > Hosts MAY support mobile node functionality described in Section 8.5 > of [RFC3775], including support of generic packet tunneling [RFC2473] > and secure home agent communications [RFC4877]. > > Hosts SHOULD support route optimization requirements for > correspondent nodes described in Section 8.2 of [RFC3775]. > > Routers SHOULD support the generic mobility-related requirements for > all IPv6 routers described in Section 8.3 of [RFC3775]. Routers MAY > support the home agent functionality described in Section 8.4 of > [RFC3775], including support of [RFC2473] and [RFC4877].
I think the above text needs updating. As with SEND, I do not believe we have sufficient implementation and deployment experience to make a general SHOULD recommendations for RO. I would like to get a better sense of what the implementation status of MIPv6 is. AFAIK, it is not implemented in mainstream products (or distributions) at this time. Moreover, RO is new technology to IPv6 (MIPv4 does not have it), making it even more important to get real deployment and operational experience before making a broad SHOULD recommendation. The first MAY recommendation basically says that implementing mobility functions (i.e., being a mobile node) is completely optional. That seems fine. The second recommendation says that generic hosts SHOULD implement RO. But, RO primarily benefits mobile nodes, so it is in some sense an unfunded mandate for hosts. Hosts pay a cost for implementing RO, but don't see much, if any, benefit. Moreover, it is unclear at this point that we have any significant deployment experience with this technology. W.r.t. RO, discussion in the past has also raised concerns as to whether larger content servers (i.e., amazons and googles) would be willing to support RO. They raised concerns about scalability, etc. Thus, in the absence of significant deployment and operational experience, I think it is premature to broadly recommend implemenation of RO. A MAY for general hosts seems about the best we can do. Regarding the last recommendation, that Routers SHOULD support generic mobility-related requirements, this means (from RFC3775): > 8.3. All IPv6 Routers > > All IPv6 routers, even those not serving as a home agent for Mobile > IPv6, have an effect on how well mobile nodes can communicate: > > o Every IPv6 router SHOULD be able to send an Advertisement Interval > option (Section 7.3) in each of its Router Advertisements [12], to > aid movement detection by mobile nodes (as in Section 11.5.1). > The use of this option in Router Advertisements SHOULD be > configurable. > > o Every IPv6 router SHOULD be able to support sending unsolicited > multicast Router Advertisements at the faster rate described in > Section 7.5. If the router supports a faster rate, the used rate > MUST be configurable. > > o Each router SHOULD include at least one prefix with the Router > Address (R) bit set and with its full IP address in its Router > Advertisements (as described in Section 7.2). > > o Routers supporting filtering packets with routing headers SHOULD > support different rules for type 0 and type 2 routing headers (see > Section 6.4) so that filtering of source routed packets (type 0) > will not necessarily limit Mobile IPv6 traffic which is delivered > via type 2 routing headers. I think that these recommendations are generally OK. Indeed, I think it is a bit unfortunate that those recommendations are hidden within the MIPv6 spec as opposed to being merged in with the ND spec, but that isn't something node requirments can address. Comments? Thomas -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
