diff --git a/api/system-current.txt b/api/system-current.txt
index 7a4aba8..aa5fc77 100755
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -9808,7 +9808,8 @@
     field public static final int DIALSTRING_USSD = 2; // 0x2
     field public static final String EXTRA_ADDITIONAL_CALL_INFO = "AdditionalCallInfo";
     field public static final String EXTRA_ADDITIONAL_SIP_INVITE_FIELDS = "android.telephony.ims.extra.ADDITIONAL_SIP_INVITE_FIELDS";
-    field public static final String EXTRA_CALL_RAT_TYPE = "CallRadioTech";
+    field public static final String EXTRA_CALL_NETWORK_TYPE = "android.telephony.ims.extra.CALL_NETWORK_TYPE";
+    field @Deprecated public static final String EXTRA_CALL_RAT_TYPE = "CallRadioTech";
     field public static final String EXTRA_CHILD_NUMBER = "ChildNum";
     field public static final String EXTRA_CNA = "cna";
     field public static final String EXTRA_CNAP = "cnap";
@@ -9840,8 +9841,8 @@
     method public void callSessionConferenceExtendReceived(android.telephony.ims.stub.ImsCallSessionImplBase, android.telephony.ims.ImsCallProfile);
     method public void callSessionConferenceExtended(android.telephony.ims.stub.ImsCallSessionImplBase, android.telephony.ims.ImsCallProfile);
     method public void callSessionConferenceStateUpdated(android.telephony.ims.ImsConferenceState);
-    method public void callSessionHandover(int, int, android.telephony.ims.ImsReasonInfo);
-    method public void callSessionHandoverFailed(int, int, android.telephony.ims.ImsReasonInfo);
+    method @Deprecated public void callSessionHandover(int, int, android.telephony.ims.ImsReasonInfo);
+    method @Deprecated public void callSessionHandoverFailed(int, int, android.telephony.ims.ImsReasonInfo);
     method public void callSessionHeld(android.telephony.ims.ImsCallProfile);
     method public void callSessionHoldFailed(android.telephony.ims.ImsReasonInfo);
     method public void callSessionHoldReceived(android.telephony.ims.ImsCallProfile);
@@ -9849,7 +9850,7 @@
     method public void callSessionInitiatedFailed(android.telephony.ims.ImsReasonInfo);
     method public void callSessionInviteParticipantsRequestDelivered();
     method public void callSessionInviteParticipantsRequestFailed(android.telephony.ims.ImsReasonInfo);
-    method public void callSessionMayHandover(int, int);
+    method @Deprecated public void callSessionMayHandover(int, int);
     method public void callSessionMergeComplete(android.telephony.ims.stub.ImsCallSessionImplBase);
     method public void callSessionMergeFailed(android.telephony.ims.ImsReasonInfo);
     method public void callSessionMergeStarted(android.telephony.ims.stub.ImsCallSessionImplBase, android.telephony.ims.ImsCallProfile);
@@ -9871,6 +9872,9 @@
     method public void callSessionUpdateReceived(android.telephony.ims.ImsCallProfile);
     method public void callSessionUpdated(android.telephony.ims.ImsCallProfile);
     method public void callSessionUssdMessageReceived(int, String);
+    method public void onHandover(int, int, @Nullable android.telephony.ims.ImsReasonInfo);
+    method public void onHandoverFailed(int, int, @NonNull android.telephony.ims.ImsReasonInfo);
+    method public void onMayHandover(int, int);
   }
 
   public final class ImsConferenceState implements android.os.Parcelable {
diff --git a/api/test-current.txt b/api/test-current.txt
index e4997b7..d81cb22 100644
--- a/api/test-current.txt
+++ b/api/test-current.txt
@@ -3153,7 +3153,8 @@
     field public static final int DIALSTRING_USSD = 2; // 0x2
     field public static final String EXTRA_ADDITIONAL_CALL_INFO = "AdditionalCallInfo";
     field public static final String EXTRA_ADDITIONAL_SIP_INVITE_FIELDS = "android.telephony.ims.extra.ADDITIONAL_SIP_INVITE_FIELDS";
-    field public static final String EXTRA_CALL_RAT_TYPE = "CallRadioTech";
+    field public static final String EXTRA_CALL_NETWORK_TYPE = "android.telephony.ims.extra.CALL_NETWORK_TYPE";
+    field @Deprecated public static final String EXTRA_CALL_RAT_TYPE = "CallRadioTech";
     field public static final String EXTRA_CHILD_NUMBER = "ChildNum";
     field public static final String EXTRA_CNA = "cna";
     field public static final String EXTRA_CNAP = "cnap";
@@ -3186,8 +3187,8 @@
     method public void callSessionConferenceExtendReceived(android.telephony.ims.stub.ImsCallSessionImplBase, android.telephony.ims.ImsCallProfile);
     method public void callSessionConferenceExtended(android.telephony.ims.stub.ImsCallSessionImplBase, android.telephony.ims.ImsCallProfile);
     method public void callSessionConferenceStateUpdated(android.telephony.ims.ImsConferenceState);
-    method public void callSessionHandover(int, int, android.telephony.ims.ImsReasonInfo);
-    method public void callSessionHandoverFailed(int, int, android.telephony.ims.ImsReasonInfo);
+    method @Deprecated public void callSessionHandover(int, int, android.telephony.ims.ImsReasonInfo);
+    method @Deprecated public void callSessionHandoverFailed(int, int, android.telephony.ims.ImsReasonInfo);
     method public void callSessionHeld(android.telephony.ims.ImsCallProfile);
     method public void callSessionHoldFailed(android.telephony.ims.ImsReasonInfo);
     method public void callSessionHoldReceived(android.telephony.ims.ImsCallProfile);
@@ -3195,7 +3196,7 @@
     method public void callSessionInitiatedFailed(android.telephony.ims.ImsReasonInfo);
     method public void callSessionInviteParticipantsRequestDelivered();
     method public void callSessionInviteParticipantsRequestFailed(android.telephony.ims.ImsReasonInfo);
-    method public void callSessionMayHandover(int, int);
+    method @Deprecated public void callSessionMayHandover(int, int);
     method public void callSessionMergeComplete(android.telephony.ims.stub.ImsCallSessionImplBase);
     method public void callSessionMergeFailed(android.telephony.ims.ImsReasonInfo);
     method public void callSessionMergeStarted(android.telephony.ims.stub.ImsCallSessionImplBase, android.telephony.ims.ImsCallProfile);
@@ -3217,6 +3218,9 @@
     method public void callSessionUpdateReceived(android.telephony.ims.ImsCallProfile);
     method public void callSessionUpdated(android.telephony.ims.ImsCallProfile);
     method public void callSessionUssdMessageReceived(int, String);
+    method public void onHandover(int, int, @Nullable android.telephony.ims.ImsReasonInfo);
+    method public void onHandoverFailed(int, int, @NonNull android.telephony.ims.ImsReasonInfo);
+    method public void onMayHandover(int, int);
   }
 
   public final class ImsConferenceState implements android.os.Parcelable {
diff --git a/telephony/java/android/telephony/ims/ImsCallProfile.java b/telephony/java/android/telephony/ims/ImsCallProfile.java
index d6dea2c..a7d553b 100644
--- a/telephony/java/android/telephony/ims/ImsCallProfile.java
+++ b/telephony/java/android/telephony/ims/ImsCallProfile.java
@@ -294,15 +294,30 @@
      *      updateImsCallRatFromExtras(Bundle)} to determine whether to set the
      * {@link android.telecom.TelecomManager#EXTRA_CALL_NETWORK_TYPE} extra value and
      * {@link android.telecom.Connection#PROPERTY_WIFI} property on a connection.
+     * @deprecated the constants associated with this extra are hidden, instead use
+     * {@link #EXTRA_CALL_NETWORK_TYPE}.
      */
+    @Deprecated
     public static final String EXTRA_CALL_RAT_TYPE = "CallRadioTech";
 
     /**
+     * Extra key with an {@code int} value which can be set in {@link #setCallExtraInt(String, int)}
+     * to indicate the network type used for a call.
+     * <p>
+     * Valid values are defined by {@code TelephonyManager.NETWORK_TYPE_*} constants. An example may
+     * be {@link android.telephony.TelephonyManager#NETWORK_TYPE_LTE}.
+     */
+    public static final String EXTRA_CALL_NETWORK_TYPE =
+            "android.telephony.ims.extra.CALL_NETWORK_TYPE";
+
+    /**
      * Similar to {@link #EXTRA_CALL_RAT_TYPE}, except with a lowercase 'c'.  Used to ensure
      * compatibility with modems that are non-compliant with the {@link #EXTRA_CALL_RAT_TYPE}
      * extra key.  Should be removed when the non-compliant modems are fixed.
      * @hide
+     * @deprecated Use {@link #EXTRA_CALL_NETWORK_TYPE} instead.
      */
+    @Deprecated
     public static final String EXTRA_CALL_RAT_TYPE_ALT = "callRadioTech";
 
     /** @hide */
diff --git a/telephony/java/android/telephony/ims/ImsCallSession.java b/telephony/java/android/telephony/ims/ImsCallSession.java
index 5adc99e..1b583fd 100644
--- a/telephony/java/android/telephony/ims/ImsCallSession.java
+++ b/telephony/java/android/telephony/ims/ImsCallSession.java
@@ -25,8 +25,6 @@
 import com.android.ims.internal.IImsCallSession;
 import com.android.ims.internal.IImsVideoCallProvider;
 
-import java.util.Objects;
-
 /**
  * Provides the call initiation/termination, and media exchange between two IMS endpoints.
  * It directly communicates with IMS service which implements the IMS protocol behavior.
@@ -346,7 +344,7 @@
         }
 
         /**
-         * Called when an {@link ImsCallSession} may handover from one radio technology to another.
+         * Called when an {@link ImsCallSession} may handover from one network type to another.
          * For example, the session may handover from WIFI to LTE if conditions are right.
          * <p>
          * If handover is attempted,
@@ -355,24 +353,24 @@
          * called to indicate the success or failure of the handover.
          *
          * @param session IMS session object
-         * @param srcAccessTech original access technology
-         * @param targetAccessTech new access technology
+         * @param srcNetworkType original network type
+         * @param targetNetworkType new network type
          */
-        public void callSessionMayHandover(ImsCallSession session, int srcAccessTech,
-                int targetAccessTech) {
+        public void callSessionMayHandover(ImsCallSession session, int srcNetworkType,
+                int targetNetworkType) {
             // no-op
         }
 
         /**
-         * Called when session access technology changes
+         * Called when session network type changes
          *
          * @param session IMS session object
-         * @param srcAccessTech original access technology
-         * @param targetAccessTech new access technology
+         * @param srcNetworkType original network type
+         * @param targetNetworkType new network type
          * @param reasonInfo
          */
         public void callSessionHandover(ImsCallSession session,
-                                 int srcAccessTech, int targetAccessTech,
+                                 int srcNetworkType, int targetNetworkType,
                                  ImsReasonInfo reasonInfo) {
             // no-op
         }
@@ -381,12 +379,12 @@
          * Called when session access technology change fails
          *
          * @param session IMS session object
-         * @param srcAccessTech original access technology
-         * @param targetAccessTech new access technology
+         * @param srcNetworkType original access technology
+         * @param targetNetworkType new access technology
          * @param reasonInfo handover failure reason
          */
         public void callSessionHandoverFailed(ImsCallSession session,
-                                       int srcAccessTech, int targetAccessTech,
+                                       int srcNetworkType, int targetNetworkType,
                                        ImsReasonInfo reasonInfo) {
             // no-op
         }
@@ -1303,20 +1301,19 @@
         /**
          * Notifies of a case where a {@link ImsCallSession} may
          * potentially handover from one radio technology to another.
-         * @param srcAccessTech The source radio access technology; one of the access technology
-         *                      constants defined in {@link android.telephony.ServiceState}.  For
-         *                      example
-         *                      {@link android.telephony.ServiceState#RIL_RADIO_TECHNOLOGY_LTE}.
-         * @param targetAccessTech The target radio access technology; one of the access technology
-         *                      constants defined in {@link android.telephony.ServiceState}.  For
-         *                      example
-         *                      {@link android.telephony.ServiceState#RIL_RADIO_TECHNOLOGY_LTE}.
+         * @param srcNetworkType The source network type; one of the network type constants defined
+         *                       in {@link android.telephony.TelephonyManager}.  For example
+         *                      {@link android.telephony.TelephonyManager#NETWORK_TYPE_LTE}.
+         * @param targetNetworkType The target radio access technology; one of the network type
+         *                          constants defined in {@link android.telephony.TelephonyManager}.
+         *                          For example
+         *                          {@link android.telephony.TelephonyManager#NETWORK_TYPE_LTE}.
          */
         @Override
-        public void callSessionMayHandover(int srcAccessTech, int targetAccessTech) {
+        public void callSessionMayHandover(int srcNetworkType, int targetNetworkType) {
             if (mListener != null) {
-                mListener.callSessionMayHandover(ImsCallSession.this, srcAccessTech,
-                        targetAccessTech);
+                mListener.callSessionMayHandover(ImsCallSession.this, srcNetworkType,
+                        targetNetworkType);
             }
         }
 
@@ -1324,11 +1321,11 @@
          * Notifies of handover information for this call
          */
         @Override
-        public void callSessionHandover(int srcAccessTech, int targetAccessTech,
+        public void callSessionHandover(int srcNetworkType, int targetNetworkType,
                 ImsReasonInfo reasonInfo) {
             if (mListener != null) {
-                mListener.callSessionHandover(ImsCallSession.this, srcAccessTech,
-                        targetAccessTech, reasonInfo);
+                mListener.callSessionHandover(ImsCallSession.this, srcNetworkType,
+                        targetNetworkType, reasonInfo);
             }
         }
 
@@ -1336,11 +1333,11 @@
          * Notifies of handover failure info for this call
          */
         @Override
-        public void callSessionHandoverFailed(int srcAccessTech, int targetAccessTech,
+        public void callSessionHandoverFailed(int srcNetworkType, int targetNetworkType,
                 ImsReasonInfo reasonInfo) {
             if (mListener != null) {
-                mListener.callSessionHandoverFailed(ImsCallSession.this, srcAccessTech,
-                        targetAccessTech, reasonInfo);
+                mListener.callSessionHandoverFailed(ImsCallSession.this, srcNetworkType,
+                        targetNetworkType, reasonInfo);
             }
         }
 
diff --git a/telephony/java/android/telephony/ims/ImsCallSessionListener.java b/telephony/java/android/telephony/ims/ImsCallSessionListener.java
index e11886f..025721c 100644
--- a/telephony/java/android/telephony/ims/ImsCallSessionListener.java
+++ b/telephony/java/android/telephony/ims/ImsCallSessionListener.java
@@ -17,10 +17,13 @@
 package android.telephony.ims;
 
 import android.annotation.NonNull;
+import android.annotation.Nullable;
 import android.annotation.SystemApi;
 import android.annotation.TestApi;
 import android.os.RemoteException;
+import android.telephony.Annotation;
 import android.telephony.CallQuality;
+import android.telephony.ServiceState;
 import android.telephony.ims.aidl.IImsCallSessionListener;
 import android.telephony.ims.stub.ImsCallSessionImplBase;
 
@@ -476,11 +479,27 @@
      * @param targetAccessTech The target radio access technology; one of the access technology
      * constants defined in {@link android.telephony.ServiceState}. For example
      * {@link android.telephony.ServiceState#RIL_RADIO_TECHNOLOGY_LTE}.
+     * @deprecated Uses hidden constants for radio access technology, use
+     * {@link #onMayHandover(int, int)} instead.
      */
-    public void callSessionMayHandover(int srcAccessTech, int targetAccessTech)
-    {
+    @Deprecated
+    public void callSessionMayHandover(int srcAccessTech, int targetAccessTech) {
+        // Use new API internally.
+        onMayHandover(ServiceState.rilRadioTechnologyToNetworkType(srcAccessTech),
+                ServiceState.rilRadioTechnologyToNetworkType(targetAccessTech));
+    }
+
+    /**
+     * Notify the framework that the associated {@link ImsCallSession} may handover from one network
+     * type to another.
+     *
+     * @param srcNetworkType The source network type.
+     * @param targetNetworkType The target network type.
+     */
+    public void onMayHandover(@Annotation.NetworkType int srcNetworkType,
+            @Annotation.NetworkType int targetNetworkType) {
         try {
-            mListener.callSessionMayHandover(srcAccessTech, targetAccessTech);
+            mListener.callSessionMayHandover(srcNetworkType, targetNetworkType);
         } catch (RemoteException e) {
             throw new RuntimeException(e);
         }
@@ -494,11 +513,29 @@
      * @param targetAccessTech new access technology, defined in
      * {@link android.telephony.ServiceState}.
      * @param reasonInfo The {@link ImsReasonInfo} associated with this handover.
+     * @deprecated Uses hidden radio access technology constants, use
+     * {@link #onHandover(int, int, ImsReasonInfo)} instead.
      */
+    @Deprecated
     public void callSessionHandover(int srcAccessTech, int targetAccessTech,
             ImsReasonInfo reasonInfo) {
+        // Use new API internally.
+        onHandover(ServiceState.rilRadioTechnologyToNetworkType(srcAccessTech),
+                ServiceState.rilRadioTechnologyToNetworkType(targetAccessTech), reasonInfo);
+    }
+
+    /**
+     * Notify the framework that the associated {@link ImsCallSession} has handed over from one
+     * network type to another.
+     *
+     * @param srcNetworkType original network type.
+     * @param targetNetworkType target network type after handover..
+     * @param reasonInfo An optional {@link ImsReasonInfo} associated with this handover.
+     */
+    public void onHandover(@Annotation.NetworkType int srcNetworkType,
+            @Annotation.NetworkType int targetNetworkType, @Nullable ImsReasonInfo reasonInfo) {
         try {
-            mListener.callSessionHandover(srcAccessTech, targetAccessTech, reasonInfo);
+            mListener.callSessionHandover(srcNetworkType, targetNetworkType, reasonInfo);
         } catch (RemoteException e) {
             throw new RuntimeException(e);
         }
@@ -510,11 +547,28 @@
      * @param srcAccessTech original access technology
      * @param targetAccessTech new access technology
      * @param reasonInfo An {@link ImsReasonInfo} detailing the reason for the failure.
+     * @deprecated Uses hidden radio access technology constants, use
+     * {@link #onHandoverFailed(int, int, ImsReasonInfo)} instead
      */
+    @Deprecated
     public void callSessionHandoverFailed(int srcAccessTech, int targetAccessTech,
             ImsReasonInfo reasonInfo) {
+        // Use new API internally.
+        onHandoverFailed(ServiceState.rilRadioTechnologyToNetworkType(srcAccessTech),
+                ServiceState.rilRadioTechnologyToNetworkType(targetAccessTech), reasonInfo);
+    }
+
+    /**
+     * The IMS call session's access technology change has failed..
+     *
+     * @param srcNetworkType original network type.
+     * @param targetNetworkType target network type that the handover failed for.
+     * @param reasonInfo An {@link ImsReasonInfo} detailing the reason for the failure.
+     */
+    public void onHandoverFailed(@Annotation.NetworkType int srcNetworkType,
+            @Annotation.NetworkType int targetNetworkType, @NonNull ImsReasonInfo reasonInfo) {
         try {
-            mListener.callSessionHandoverFailed(srcAccessTech, targetAccessTech, reasonInfo);
+            mListener.callSessionHandoverFailed(srcNetworkType, targetNetworkType, reasonInfo);
         } catch (RemoteException e) {
             throw new RuntimeException(e);
         }
diff --git a/telephony/java/android/telephony/ims/aidl/IImsCallSessionListener.aidl b/telephony/java/android/telephony/ims/aidl/IImsCallSessionListener.aidl
index d64e67a..cc2ebb9 100644
--- a/telephony/java/android/telephony/ims/aidl/IImsCallSessionListener.aidl
+++ b/telephony/java/android/telephony/ims/aidl/IImsCallSessionListener.aidl
@@ -92,11 +92,11 @@
     /**
      * Notifies of handover information for this call
      */
-    void callSessionHandover(int srcAccessTech, int targetAccessTech,
+    void callSessionHandover(int srcNetworkType, int targetNetworkType,
             in ImsReasonInfo reasonInfo);
-    void callSessionHandoverFailed(int srcAccessTech, int targetAccessTech,
+    void callSessionHandoverFailed(int srcNetworkType, int targetNetworkType,
             in ImsReasonInfo reasonInfo);
-    void callSessionMayHandover(int srcAccessTech, int targetAccessTech);
+    void callSessionMayHandover(int srcNetworkType, int targetNetworkType);
 
     /**
      * Notifies the TTY mode change by remote party.
diff --git a/telephony/java/android/telephony/ims/compat/stub/ImsCallSessionImplBase.java b/telephony/java/android/telephony/ims/compat/stub/ImsCallSessionImplBase.java
index acab738..75bd6a7 100644
--- a/telephony/java/android/telephony/ims/compat/stub/ImsCallSessionImplBase.java
+++ b/telephony/java/android/telephony/ims/compat/stub/ImsCallSessionImplBase.java
@@ -20,6 +20,7 @@
 import android.os.Message;
 import android.os.RemoteException;
 import android.telephony.CallQuality;
+import android.telephony.ServiceState;
 import android.telephony.ims.ImsCallProfile;
 import android.telephony.ims.ImsCallSession;
 import android.telephony.ims.ImsConferenceState;
@@ -547,19 +548,25 @@
         @Override
         public void callSessionHandover(IImsCallSession i, int srcAccessTech, int targetAccessTech,
                 ImsReasonInfo reasonInfo) throws RemoteException {
-            mNewListener.callSessionHandover(srcAccessTech, targetAccessTech, reasonInfo);
+            mNewListener.callSessionHandover(
+                    ServiceState.rilRadioTechnologyToNetworkType(srcAccessTech),
+                    ServiceState.rilRadioTechnologyToNetworkType(targetAccessTech), reasonInfo);
         }
 
         @Override
         public void callSessionHandoverFailed(IImsCallSession i, int srcAccessTech,
                 int targetAccessTech, ImsReasonInfo reasonInfo) throws RemoteException {
-            mNewListener.callSessionHandoverFailed(srcAccessTech, targetAccessTech, reasonInfo);
+            mNewListener.callSessionHandoverFailed(
+                    ServiceState.rilRadioTechnologyToNetworkType(srcAccessTech),
+                    ServiceState.rilRadioTechnologyToNetworkType(targetAccessTech), reasonInfo);
         }
 
         @Override
         public void callSessionMayHandover(IImsCallSession i, int srcAccessTech, int targetAccessTech)
                 throws RemoteException {
-            mNewListener.callSessionMayHandover(srcAccessTech, targetAccessTech);
+            mNewListener.callSessionMayHandover(
+                    ServiceState.rilRadioTechnologyToNetworkType(srcAccessTech),
+                    ServiceState.rilRadioTechnologyToNetworkType(targetAccessTech));
         }
 
         @Override