dslac November 2002 G. Chelius, E. Fleury L. Toutain IPv6 router auto-configuration using OSPFv3

dslac November 2002 Objectives Home networking Multi-technology (Ethernet, , Bluetooth, IEEE1394, power lines…) Complex topology Possible loops, possible multi-homing No IPv6 network administration skill => Difficult to manually assign subnet numbers Use of OSPFv3 to automatically assign subnet numbers Use of the OSPF database synchronization Definition of 3 new LSA types

dslac November 2002 Announcement of prefix numbers (TLA) TLA-Site LSA Originated by edge routers Flooding scope: site Announce an available prefix throughout the network Multi-homing Several prefix database entries Different prefix originators Upon reception, routers update global prefixes If no global prefix entry, use the site local prefix

dslac November 2002 How to get a subnet value consensus on a link SLA-Link LSA Originated by the link’s Designated Router (DR) Flooding scope: link Create a consensus on the link (subnet number, length, Link ID) Mapping between Link ID and subnet number Link IDs are large numbers to avoid collisions At link creation DR imposes its Link ID & subnet number

dslac November 2002 Link merging or partitioning Election of a new designated router If old DR is dead (may be link partitioning) New Link ID & new subnet number If old DR still present on the link Same Link ID & same subnet number Link merging One of the two Link ID & subnet number disappears

dslac November 2002 Announcement of allocated subnet numbers (SLA) SLA-Area LSA Originated by the link’s designated router Flooding scope: area Announce allocated TLA:SLA and Link IDs throughout the area Avoid collision when a new subnet number is chosen Knowledge of attributed subnet numbers using SLA-Area entries Collision detection when another Link ID use the same TLA:SLA Smallest Link ID renumbers its subnet number

dslac November 2002 Issues Auto-configuration of OSPFv3: router IDs 32 bits Manually configured… What do we want to be unique ? SLA value (only one SLA per link) or TLA:SLA value (decreases collision risk, increases complexity) Implementation status Implemented in Zebra ospf6d See