diff --git a/telephony/java/android/telephony/CarrierConfigManager.java b/telephony/java/android/telephony/CarrierConfigManager.java
index 7abad72..c51dd34 100755
--- a/telephony/java/android/telephony/CarrierConfigManager.java
+++ b/telephony/java/android/telephony/CarrierConfigManager.java
@@ -1446,6 +1446,50 @@
             "apn_settings_default_apn_types_string_array";
 
     /**
+     * Configs used for APN setup.
+     */
+    public static final class Apn {
+        /** Prefix of all Apn.KEY_* constants. */
+        public static final String KEY_PREFIX = "apn.";
+
+        /** IPv4 internet protocol */
+        public static final String PROTOCOL_IPV4 = "IP";
+        /** IPv6 internet protocol */
+        public static final String PROTOCOL_IPV6 = "IPV6";
+        /** IPv4 or IPv6 internet protocol */
+        public static final String PROTOCOL_IPV4V6 = "IPV4V6";
+
+        /**
+         * Default value of APN protocol field if not specified by user when adding/modifying
+         * an APN.
+         *
+         * Available options are: {@link #PROTOCOL_IPV4}, {@link #PROTOCOL_IPV6},
+         * {@link #PROTOCOL_IPV4V6}
+         */
+        public static final String KEY_SETTINGS_DEFAULT_PROTOCOL_STRING =
+                KEY_PREFIX + "settings_default_protocol_string";
+
+        /**
+         * Default value of APN roaming protocol field if not specified by user when
+         * adding/modifying an APN.
+         *
+         * Available options are: {@link #PROTOCOL_IPV4}, {@link #PROTOCOL_IPV6},
+         * {@link #PROTOCOL_IPV4V6}
+         */
+        public static final String KEY_SETTINGS_DEFAULT_ROAMING_PROTOCOL_STRING =
+                KEY_PREFIX + "settings_default_roaming_protocol_string";
+
+        private Apn() {}
+
+        private static PersistableBundle getDefaults() {
+            PersistableBundle defaults = new PersistableBundle();
+            defaults.putString(KEY_SETTINGS_DEFAULT_PROTOCOL_STRING, "");
+            defaults.putString(KEY_SETTINGS_DEFAULT_ROAMING_PROTOCOL_STRING, "");
+            return defaults;
+        }
+    }
+
+    /**
      * Boolean indicating if intent for emergency call state changes should be broadcast
      * @hide
      */
@@ -3903,6 +3947,8 @@
         sDefaults.putStringArray(KEY_READ_ONLY_APN_TYPES_STRING_ARRAY, new String[] {"dun"});
         sDefaults.putStringArray(KEY_READ_ONLY_APN_FIELDS_STRING_ARRAY, null);
         sDefaults.putStringArray(KEY_APN_SETTINGS_DEFAULT_APN_TYPES_STRING_ARRAY, null);
+        sDefaults.putAll(Apn.getDefaults());
+
         sDefaults.putBoolean(KEY_BROADCAST_EMERGENCY_CALL_STATE_CHANGES_BOOL, false);
         sDefaults.putBoolean(KEY_ALWAYS_SHOW_EMERGENCY_ALERT_ONOFF_BOOL, false);
         sDefaults.putStringArray(KEY_CARRIER_DATA_CALL_RETRY_CONFIG_STRINGS, new String[]{