"The Access Network Identifier (ANI) mobility option was introduced in RFC 6757@ ""Access Network Identifier (ANI) Option for Proxy Mobile IPv6"". This enables a Mobile Access Gateway (MAG) to convey identifiers like the network identifier@ geolocation@ and operator identifier. This specification extends the Access Network Identifier mobility option with sub-options to carry the civic location and the MAG group identifier. This specification also defines an ANI Update- Timer sub-option that determines when and how often the ANI option will be updated."