d include: INTEGER; BOOLEAN; REAL; and BIT STRING. An ENUMERATED data type is one that takes one of several possible values. Other data items can be specified as optional. Table 6-8 IEEE 802. .16m MAC Management/Control Messages [1,2] 802.16- IEEE 802.16m Standard MAC Management Equivalent Message Security Connection Message Description Usage Message Attributes AAI_SCD This message is transmitted Broadcast of System Broadcast by the BS at a periodic interval system information Configuration to define the system and parameters Descriptor configuration. (Additional Broadcast Information not otherwise transmitted in the superframe headers). AAI_LBS-ADV AAI_LBS-ADV is a MAC Broadcast of LBS Advertisement Broadcast control message broadcast system information by the BS to provide the MS with topographical information of the neighboring base stations, which can be used by the MS for triangularization or trilaterization to enable location determination. This message may also contain time and frequency information to aid satellite based, e.g., GPS, receivers for improved performance. AAI_RNG-REQ A message that is transmitted Network Entry/ RNG-REQ Ranging Request Null: during initial Initial by the MS at initialization and Re-entry ranging procedure Ranging or later periodically to determine when there is no Unicast network delay and to request security association power and/or DL burst profile already established change. or updated CMAC: Other cases. AAI_RNG-RSP A message that is transmitted Network Entry/ RNG-RSP Null: during ranging Initial Ranging Response by the BS in response to an Re-entry procedure when Ranging or AAI_RNG-REQ message. In there is no security Unicast addition, it may also be association already transmitted asynchronously established or to send corrections based on updated. measurements that have Encrypted/ICV: been made on other received Other cases. data or MAC messages. AAI_RNG-ACK Aggregated CDMA Ranging Network Entry/ Broadcast Ranging Acknowledge is a message Re-entry Acknowledgement that pro