6) suffix Pref64/56 v4 (24) suffix Pref64/64 v4 (32) suffix WPK/96 or Pref64/96 v4 (32) Figure 5.3 IPv4-embedded IPv6 address format for translation purposes. Table 5.1 IPv4-embedded IPv6 address synthesis examples Network-specific prefix IPv4 address IPv4-embedded IPv6 address 2001:db8::/32 192.0.2.1 2001:db8:c000:201:: 2001:db8:1100::/40 192.0.2.2 2001:db8:11c0:2:2:: 2001:db8:1122::/48 192.0.2.3 2001:db8:1122:c000:2:300:: 2001:db8:1122:3300::/56 192.0.2.4 2001:db8:1122:33c0:0:204:: 2001:db8:1122:3344::/64 192.0.2.5 2001:db8:1122:3344:c0:2:500:: 2001:db8:1122:3344::/96 192.0.2.6 2001:db8:1122:3344::192.0.2.6 Well-known prefix IPv4 address IPv4-embedded IPv6 address 64:ff9b::/96 192.0.2.7 64:ff9b::192.0.2.7 that should also be reachable from the IPv4 Internet, there must be a matching public IPv4 address. Syntactically IPv4-translatable IPv6 address does not differ from IPv4- converted IPv6 address. Table 5.1 illustrates how to synthesize IPv6-embedded addresses out of both NSP and WKP. The textual format follows the standard IPv6 text representation of IPv6 addresses [30]. Stateful NAT64 Deployment RFC 6146 [14] describes a stateful version of NAT64. It is probably the most popular fla- vor of deployed NAT64s, because it can provide IPv4 connectivity to IPv6 hosts using far less public IPv4 addresses than stateless NAT64. In Figure 5.4 we show an example archi- tecture of a NAT64/DNS64 deployment within a mobile operator network, where NAT64 function could be embedded inside a PGW. Alternatively, the translation function could be a separate node. It does not really matter from the translation outcome point of view. There are certain benefits in combining the mobile network gateway and the translation function. Those usually boil down to more fine-grained subscription awareness within a combined Deploying IPv6 in 3GPP Networks DNS64 Stateful ((q)) GGSN/PGW NAT64 Internet Public IPv4 Router Combined or separate Native IPv6 functions Figure 5.4 An example of DNS64 and a stateful NAT64 that can be integral to a GGSN