MS in Lzone; Zone Switching Mode: if set to 1, the MS maintains its data communication with the BS in LZone while performing network re-entry with the MZone; otherwise, the MS interrupts data communication in LZone before performing network re-entry with the MZone. Note that the security master key is shared between LZone and MZone during zone switching. The zone switching TLV coded parameter may also include the following information: Temporary STID to be used in the Mzone; HO Ranging Initiation Deadline which denotes the valid time for the temporary STID. After receiving the zone-switching command through an RNG-RSP message in the LZone, the MS performs network re-entry with the MZone. The MS maintains its normal operation in the LZone (i.e., exchanging user data with the BS in the LZone) while performing network re-entry in the MZone, if the data path in LZone has been established before the start of zone switching and the Zone Switching Mode in the zone-switching TLV-coded parameter is set to 1. If synchronization with the MZone has not been accomplished, the MS starts network re-entry in the MZone by performing DL synchronization with the MZone preambles using the system information provided in the zone- switching TLV-coded parameter. The MS acquires the system information transmitted in the MZone by listening to the new BS broadcast channels. The MS appends the CMAC tuple to the AAI_RNG-REQ message, if the security context is available for the MZone. The BS then responds with an AAI_RNG-RSP message. If the CMAC tuple 6.5 Quality of service in the AAI_RNG-REQ message is valid, the BS responds to the MS with the encrypted AAI_RNG- RSP message. If the CMAC in the AAI_RNG-REQ message is invalid or not included, the BS instructs the MS to initiate network entry procedure. If an UL grant is provided in the MZone in Zone_Switch_Action_Time, the MS uses the grant to send an AAI_RNG-REQ message with HO Ranging Purpose Indication set to Zone Switch. Otherwise, the MS will request UL bandwidth to send the AAI_RNG-REQ 