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IPv6 Address Assignment and Route Selection for End-to-End Multihoming draft-ohira-assign-select-e2e-multihome-01.txt Kenji Ohira Kyoto University IETF #57 in Viena 1 Overview of our draft • Goal: – Not an end host but each end application can decide a route. (End-to-end multihoming) • Our proposal: – A multi-level hierarchical network model and address assignment. – A route is determined by selecting a pair of a source address and a destination address. – Selection is done on layer 4 or above, not on layer 3. IETF #57 in Viena 2 Hierarchical address assignment (assumption) Local ISP L Local ISP M L:: M:: • Each ISP assign an address prefix to a site hierarchically. • Our draft shows that this model can be extended to 3 or more level model. L:A:: M:A:: Site A 2-level hierarchical model IETF #57 in Viena 3 Source address based path L:: M:: N:: selection • Selection of a pair of src/dst address immediately gives a path. L:A:s s M:A:s – The number of candidate paths is the same as the number of src/dst pairs. M:B:t N:B:t t src: M:A:s, dst: M:B:t • An end application can select a path without full-route information. • This enables: L:: M:: N:: – Redundancy • Speedy path alternation initiated by end host/applications. • Independent of L3 routing protocols. L:A:s s M:A:s t M:B:t N:B:t src: L:A:s, dst: M:B:t – Load sharing • Each end-to-end flow can use multipaths. IETF #57 in Viena 4 Implementation of site-exit router selection (1/2) to ISP L site exit router to • Source address based routing ISP M is employed in a site • Site-exit router selection is done by selecting a source address (see draft-huitema-multi6-hosts) • Such a selection is done on L4 or above L:A:host site A M:A:host – Host/application based policy decision (see draft-ohta-e2e-multihoming) IETF #57 in Viena 5 Implementation of site-exit router selection (2/2) to ISP L site exit router to To reduce the impacts on routing ISP M mechanisms, we propose: • Announce default routes to site-exit routers and intra-site routes only. – Full route is not needed • Apply source address based routing only for default route entries. L:A:host site A M:A:host – Routing loop never occurs. – Modification to hosts, routers and routing protocol is needed but is minimum. IETF #57 in Viena 6 Concluding Remarks • Site-exit router selection using source address based routing – for end-to-end redundancy/load sharing with multiple paths • Impacts on hosts, routers and routing protocols – Intra-site source address based routing is needed, but special treatment only for default routes is enough. • Impacts on L4 or above – Some mechanism is needed for proper source address selection – Transport layer survivability would be supported by • Socket API extension with LIN6 (draft-arifumi-lin6-multihome-api) • Some extension of SCTP multihoming support (RFC3257) IETF #57 in Viena 7