}; {endcode} -Notable difference from sockaddr_in(IPv4 address/port storage) is that it has scope id. Scope id denotes a ethernet interface in a system. Scope id binds IP address shown in sockaddr_in6 to specific ethernet interface. That binding is necessary because some IPv6 addresses are limited to an ethernet interface. Google about 'link local address' would be helpful. +Notable difference from sockaddr_in(IPv4 address/port storage) is that it has scope id. Scope id denotes a ethernet interface in a system. Scope id binds IP address shown in sockaddr_in6 to specific ethernet interface. That binding is necessary because some IPv6 addresses are limited to some ethernet interface. Google about 'link local address' would be helpful. Tentative unified address class is as follows