2. IETF – March 22, 2001 Improving Network Renumbering in Mobile IPv6 Changes to Tunneled Router Solicit/Advert T.J. Kniveton Nokia Research Center Mountain View, Ca.

3. Improving Network Renumbering in Mobile IPv6 50 th IETF Todays Situation Draft 13 describes how to renumber Sections 9.8, 10.16, 10.17 There is interest in cleaning up the specification to make it more efficient and implementable This presentation summarizes conversations on the mailing list and at Connectathon on improving Tunneled RSs and RAs

4. Improving Network Renumbering in Mobile IPv6 50 th IETF What are Tunneled Router Solicitations and Advertisements? Tunneled Router Advertisements are sent from the Home Agent to the Mobile Node to distribute renumbered, changed, or new prefixes from the Home link to the traveling Mobile Node Mobile Node can also request this prefix info with a Tunneled Router Solicitation

5. Improving Network Renumbering in Mobile IPv6 50 th IETF TTL= 255 What They Look Like Mobile Node can solicit prefix info from router by adding an encapsulation Home Agent sends Router Advertisement with Routing Header (as per usual) Outer Src=CoAOuter Dst = HA IPv6 ICMPv6 Inner Src=HAddrOuter Dst = HA ICMPv6 Router Solicitation TTL= 255-n Src=CoA Dst = HA IPv6 RtHdr0 ICMPv6 CoA ICMPv6 Router Solicitation TTL= 255-n

6. Improving Network Renumbering in Mobile IPv6 50 th IETF Problems: Bootstrap Does not work for bootstrap situation Mobile Node should not use unspecified address Hard to form security association with 0::0 Returning Tunneled RA with 0s in RtHdr0 is illegal HA must also keep outer encapsulation layer This section assumes, implicitly and explicitly, a preconfigured Home Address and Binding This assumption is not valid for Bootstrap

7. Improving Network Renumbering in Mobile IPv6 50 th IETF Problems: Efficiency Rules for when to send prefix info are complicated, and probably too frequent Excessive info is sent to Mobile Node Mobile need only be concerned with prefixes served by Home Agent(s), not all prefixes Encapsulation not necessary Used to preserve TTL=255, but that is still broken by responding Router Advertisement

8. Improving Network Renumbering in Mobile IPv6 50 th IETF Available Options Bootstrap Issue (no HA) can be addressed by: Relaxing Neighbor Discovery TTL rule, and Creating a rule for processing unicast, routed (i.e. TTL<255) Mobile Router Sols/Advs Or: Creating new ICMP types for Mobile Router Solicitation and Mobile Router Advertisement

9. Improving Network Renumbering in Mobile IPv6 50 th IETF Recommendation After discussion on the mailing list, creating a new ICMP type seems wiser Avoids pitfalls of overloaded semantics and flag/value meanings, and layers of definition Draft needs to be changed anyway to address mentioned problems; this is the cleanest approach Other issues such as flag cleanup, redefining and simplifying rules for prefix inclusion, and simplified rewording are also recommended I have already done some of this; will distribute text