The MS shall perform a routing area update if the RA changes.Signalling towards the HLR is needed if the SGSN does not have an MM context for the MS.

• 如果移动台移动到不同的路由区；则要发起路由区更新规程.；如果新路由区的支撑节点中不包含有对应移动台的移动管理上下文；则需要向归属位置寄存器发送信令