erving BS which are not in use by the MS. Figure 11-11 illustrates an example of the procedure for neighbor BS advertisement and scanning of fully-configured carriers of serving and neighbor base stations. If the MS is capable of simultaneous processing of multiple RF carriers, it may perform scanning of the neighbor base stations while connected to one or more of its available component carriers without interruption to its normal communication with the serving BS. In this case, the MS and the BS may negotiate through AAI_SCN-REQ/RSP messages the component carriers be assigned for scanning operations to avoid resource allocation on those carriers (see Figure 11-12). Those carriers are identified by their carrier indices in AAI_SCN-REQ/RSP and AAI_SCN-REP messages. The handover from one component carrier to another associated with same BS for an MS supporting basic multi-carrier mode is the same as the primary carrier change procedure. During handover preparation, the MS may request or be instructed by the serving BS to perform multi-carrier handover using AAI_HO-REQ/AAI_HO-CMD messages. The serving BS informs the MS of primary carrier indices of the target base stations through an AAI_HO-CMD message. The serving BS may communicate with the target base stations to assist the MS in order to obtain a pre- assigned secondary carrier prior to handover execution. The serving BS will forward the information received through the AAI_MC-REQ message to the target base stations for secondary carrier assignment. When the HO_Reentry_Mode and HO_Reentry_Interleaving_Interval parameters are set to 1 and 0, respectively, the MS performs network re-entry with the target BS on one component carrier while communicating with the serving BS on another carrier. The MS may use the primary carrier to perform network re-entry with the target BS, as illustrated in Figure 11-13. It may also use another carrier other than its original primary carrier for network re-entry procedures, as shown in Figure 11-13. In this case, the disconnect tim