In your previous mail you wrote: We use /124s for tunnels, which avoid the problems from Pekka's draft => what is the standard which defines a /124 for a link? (anycast), but doesn't waste /64s needlessly. => we have a French expression for that: �conomie de bouts de chandelles. In a dynamically routed backbone, it's very important to actually *see* which ways a packet travels (traceroute), and occasionally to be able to do hop-by-hop diagnostics. All this requires routed ptp addresses, => no, in fact you simply need a fixed address per router. but there is no need for a /64 here. => there is no choice in the standard: all prefixes on a link are /64s. Especially EUI-64 on ptp links is a real nuisance. => I agree but this is another issue. Regards Francis.Dupont@enst-bretagne.fr