How does terminal single-stack authentication carry both Ipv4 and ipv6 addresses?

How does terminal single-stack authentication carry both Ipv4 and ipv6 addresses?

Portal authentication, single-stack authentication carrying dual-stack addresses: requires separate configuration of portal dual-ip enable, and server-side support for recognition. The addresses will be brought from the billing message. portal dual-ip enable command is used to enable the function of carrying both IPv4 and IPv6 addresses for remote Portal authentication of single-stack users. When enabled, if the terminal gets two addresses, it carries two, and if it does not get two, it carries one.