In one embodiment, a method comprises detecting, by a router, a first router advertisement message from an attachment router that provides an attachment link used by the router, the first router advertisement message specifying a first IPv6 address prefix owned by the attachment router and usable for address autoconfiguration on the attachment link. The router detects an unsolicited delegated IPv6 address prefix from the attachment router and that is available for use by the router. The router claims a second IPv6 address prefix from at least a portion of the delegated IPv6 address prefix, for use on at least one ingress link of the router.