Example embodiments presented herein are directed towards determining a Proxy Mobile Internet Protocol version 6 (?????ß) control plane used by a network node peer in an Internet Protocol version 4 (IPv4) transport network. The example embodiments provide a mechanism in PMIP protocol stack, to allow a Mobility Access Gateway/Local Mobility Anchor (MAG/LMA) node such as SGW (which may be supporting both PMIP draft and PMIP RFC) to decide which PMIP protocol stack shall be used to communicate to the peer node, i.e. LM A/MAG.