A network device receives an IPv4-in-IPv6 packet. An IPV6 header is removed. A first DSCP value in a TC field and a second DSCP value in a ToS field is stored in a database. The IPv4 packet is forwarded upstream and a return IPv4 packet is received. The returned IPv4 packet is encapsulated to form an IPV6 packet. The first DSCP value and the second DSCP value are retrieved from the database. Based on the at least one policy, the second DSCP value is inserted into an IPV4 ToS field and into an IPV6 TC field, the retrieved second DSCP value is inserted into the IPV4 ToS field and the first DSCP value is inserted into the IPV6 TC field, or the first DSCP value is inserted into the IPV6 TC field and into the IPV4 ToS field. The network device then forwards the IPv6 packet downstream.