Android Telephony 网络状态中的 NAS 信息

 NAS      ← 控制面最高层（核心网MME/UE间管理/控制消息，非接入层）

    
 RRC      ← 无线资源控制层（承载NAS信令/无线链路控制，接入层）
    
 PDCP     ← 分组数据汇聚（安全加密，头压缩，承载RRC等）
    
 RLC      ← 无线链路控制（重传、分片合并等）
    
 MAC      ← 多路复用/调度/优先级/ARQ
    
 PHY      ← 物理层（调制、解调、信道编解码等）

  |   控制面(Control Plane)            用户面(User Plane)
    
||

    
  |   +---------+                  +-------------+
    
|NAS|应用/IP|||

    
  |   +---------+                  +-------------+
    
|RRC|(无RRC)|||

    
  |   +---------+------------------+-------------+
    
|PDCP|PDCP|||

    
  |   +---------+------------------+-------------+
    
|RLC|RLC|||

    
  |   +---------+------------------+-------------+
    
|MAC|MAC|||

    
  |   +---------+------------------+-------------+
    
|PHY|PHY|||

    
  +--------------------------------+-------------+
    
       UE            无线接口           eNodeB
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     /** * Called when service state changed.
    
      */
    
     // Note that this is only called when data RAT or data registration changed. If we need to know
    
     // more "changed" events other than data RAT and data registration state, we should add
    
     // a new listening ServiceStateTracker.registerForServiceStateChanged().
    
     private void onServiceStateChanged() {
    
     // Use the raw service state instead of the mPhone.getServiceState().
    
     ServiceState newServiceState = mPhone.getServiceStateTracker().getServiceState();
    
     StringBuilder debugMessage = new StringBuilder("onServiceStateChanged: ");
    
     boolean evaluateNetworkRequests = false, evaluateDataNetworks = false;
    
  
    
     if (!mServiceState.equals(newServiceState)) {
    
         log("onServiceStateChanged: changed to " + newServiceState);
    
         for (int transport : mAccessNetworksManager.getAvailableTransports()) {
    
             NetworkRegistrationInfo oldNri = mServiceState.getNetworkRegistrationInfo(
    
                     NetworkRegistrationInfo.DOMAIN_PS, transport);
    
             NetworkRegistrationInfo newNri = newServiceState.getNetworkRegistrationInfo(
    
                     NetworkRegistrationInfo.DOMAIN_PS, transport);
    
             debugMessage.append("[").append(
    
                     AccessNetworkConstants.transportTypeToString(transport)).append(": ");
    
             debugMessage.append(oldNri != null ? TelephonyManager.getNetworkTypeName(
    
                     oldNri.getAccessNetworkTechnology()) : null);
    
             debugMessage.append("->").append(
    
                     newNri != null ? TelephonyManager.getNetworkTypeName(
    
                             newNri.getAccessNetworkTechnology()) : null).append(", ");
    
             debugMessage.append(
    
                     oldNri != null ? NetworkRegistrationInfo.registrationStateToString(
    
                             oldNri.getRegistrationState()) : null);
    
             debugMessage.append("->").append(newNri != null
    
                     ? NetworkRegistrationInfo.registrationStateToString(
    
                     newNri.getRegistrationState()) : null).append(", ");
    
             debugMessage.append(oldNri != null ? NetworkRegistrationInfo
    
                     .isNonTerrestrialNetworkToString(oldNri.isNonTerrestrialNetwork()) : null);
    
             debugMessage.append("->").append(newNri != null ? NetworkRegistrationInfo
    
                     .isNonTerrestrialNetworkToString(newNri.isNonTerrestrialNetwork()) : null)
    
                     .append("] ");
    
             if (shouldReevaluateDataNetworks(oldNri, newNri)) {
    
                 if (!hasMessages(EVENT_REEVALUATE_EXISTING_DATA_NETWORKS)) {
    
                     sendMessage(obtainMessage(EVENT_REEVALUATE_EXISTING_DATA_NETWORKS,
    
                             DataEvaluationReason.DATA_SERVICE_STATE_CHANGED));
    
                     evaluateDataNetworks = true;
    
                 }
    
             }
    
             if (shouldReevaluateNetworkRequests(mServiceState, newServiceState, transport)) {
    
                 if (!hasMessages(EVENT_REEVALUATE_UNSATISFIED_NETWORK_REQUESTS)) {
    
                     sendMessage(obtainMessage(EVENT_REEVALUATE_UNSATISFIED_NETWORK_REQUESTS,
    
                             DataEvaluationReason.DATA_SERVICE_STATE_CHANGED));
    
                     evaluateNetworkRequests = true;
    
                 }
    
             }
    
         }
    
         mServiceState = newServiceState;
    
     } else {
    
         debugMessage.append("not changed");
    
     }
    
     debugMessage.append(". Evaluating network requests is ").append(
    
             evaluateNetworkRequests ? "" : "not ").append(
    
             "needed, evaluating existing data networks is ").append(
    
             evaluateDataNetworks ? "" : "not ").append("needed.");
    
     log(debugMessage.toString());
    
     }
    
    
    
    
    java
    
    
![](https://ad.itadn.com/c/weblog/blog-img/images/2025-08-17/LHsTJtF1fbXqudyoZ7A5lDNj4pz6.png)