rising issues might show up, such as Border Gateways (BGs) or GTP aware firewalls not being IPv6 Information Element (IE) friendly. Until recently, the operator community has neglected IPv6 roaming details. Around mid 2010 the GSM Association (GSMA) started working on a white paper that covers IPv6 impacts on roaming [57]. Unfortunately, the white paper was not publicly available for non-GSMA members, although those who care about roaming in 3GPP networks most probably have some level of membership in GSMA. Based on the white paper discov- eries, a number of GSMA documents were identified that are impacted: GPRS roaming guidelines IR.33 [58], GPRS Roaming eXchange (GRX)/IP Packet eXchange - evolved GRX (IPX) backbone specification IR.34 [59], IP addressing and Autonomous System (AS) numbering guidelines IR.40 [60], GRX/IPX DNS guidelines IR.67 [61] and LTE roaming guidelines IR.88 [62]. At the time of writing, at least the IR.33 includes a number of IPv6 transition scenarios in a roaming environment. The guidelines only concern the user plane, since the GRX/IPX that tunnels the roaming GTP traffic is not going to be migrated to IPv6 transport in the foreseeable future. 5.5.7 Impact of Delayed Transition to IPv6 We have already described problems and difficulties that may occur while executing the transition to IPv6. It is important to also understand that it is not an easy task. However, not preparing for the transition to IPv6 has its impacts and costs. IPv6 Transition Mechanisms for 3GPP Networks Today, the easily available IPv4 addresses have been exhausted in the Asia-Pacific region under Asia-Pacific Network Information Center (APNIC) responsibility, and the European and Middle-East Region under Réseaux IP Européens Network Coordination Centre (RIPENCC) responsibility. Practically, this means that the traditional way of get- ting IPv4 addresses by asking for them from the RIR is no longer possible in those regions. The North American, American Registry for Internet Numbers (ARIN), region is expected to follo