A Local Mobility Anchor/Agent (LMA), on seeing a Proxy Binding Update (PBU) with a same Network Access Identifier (NAI) but with a different access technology indication or interface identifier can assign a unique prefix to a mobile node (MN) via a PBAck message. The unique prefix avoids the creation of a duplicate address that would conflict with the address assigned to another interface that was configured using a prefix provided by the LMA. This solution can enable an MN to attach to different Mobility Access Gateways (MAGs) that are in different access networks of differing technologies but attached to the same LMA (i.e. the MAGs and the LMA are in the same PMIP6 domain) and not cause conflicts in prefix assignment or confuse the LMA into thinking that the MN had performed a handover (HO).