<P> Like broadcast and multicast, anycast is a one - to - many routing topology . However, the data stream is not transmitted to all receivers, just the one which the router decides is logically closest in the network . Anycast address is an inherent feature of only IPv6 . In IPv4, anycast addressing implementations typically operate using the shortest - path metric of BGP routing and do not take into account congestion or other attributes of the path . Anycast methods are useful for global load balancing and are commonly used in distributed DNS systems . </P> <P> A host may use geolocation software to deduce the geolocation of its communicating peer . </P> <P> A public IP address, in common parlance, is a globally routable unicast IP address, meaning that the address is not an address reserved for use in private networks, such as those reserved by RFC 1918, or the various IPv6 address formats of local scope or site - local scope, for example for link - local addressing . Public IP addresses may be used for communication between hosts on the global Internet . </P> <P> For security and privacy considerations, network administrators often desire to restrict public Internet traffic within their private networks . The source and destination IP addresses contained in the headers of each IP packet are a convenient means to discriminate traffic by IP address blocking or by selectively tailoring responses to external requests to internal servers . This is achieved with firewall software running on the networks gateway router . A database of IP addresses of permissible traffic may be maintained in blacklists or whitelists . </P>

Which protocol is responsible for this assignment of ip address to a physical device