diff --git a/core/java/android/net/NetworkCapabilities.java b/core/java/android/net/NetworkCapabilities.java
index 761c033660..7c897de9b5 100644
--- a/core/java/android/net/NetworkCapabilities.java
+++ b/core/java/android/net/NetworkCapabilities.java
@@ -31,16 +31,10 @@ import java.util.Objects;
 import java.util.StringJoiner;
 
 /**
- * Representation of the capabilities of a network. This object serves two
- * purposes:
- * <ul>
- * <li>An expression of the current capabilities of an active network, typically
- * expressed through
+ * Representation of the capabilities of an active network. Instances are
+ * typically obtained through
  * {@link NetworkCallback#onCapabilitiesChanged(Network, NetworkCapabilities)}
  * or {@link ConnectivityManager#getNetworkCapabilities(Network)}.
- * <li>An expression of the future capabilities of a desired network, typically
- * expressed through {@link NetworkRequest}.
- * </ul>
  * <p>
  * This replaces the old {@link ConnectivityManager#TYPE_MOBILE} method of
  * network selection. Rather than indicate a need for Wi-Fi because an
@@ -79,7 +73,7 @@ public final class NetworkCapabilities implements Parcelable {
      */
     public void clearAll() {
         mNetworkCapabilities = mTransportTypes = 0;
-        mLinkUpBandwidthKbps = mLinkDownBandwidthKbps = 0;
+        mLinkUpBandwidthKbps = mLinkDownBandwidthKbps = LINK_BANDWIDTH_UNSPECIFIED;
         mNetworkSpecifier = null;
         mSignalStrength = SIGNAL_STRENGTH_UNSPECIFIED;
     }
@@ -359,6 +353,7 @@ public final class NetworkCapabilities implements Parcelable {
 
     /**
      * Sets all the capabilities set on this {@code NetworkCapability} instance.
+     * This overwrites any existing capabilities.
      *
      * @hide
      */
@@ -582,6 +577,7 @@ public final class NetworkCapabilities implements Parcelable {
 
     /**
      * Sets all the transports set on this {@code NetworkCapability} instance.
+     * This overwrites any existing transports.
      *
      * @hide
      */
@@ -780,7 +776,7 @@ public final class NetworkCapabilities implements Parcelable {
      * Signal strength. This is a signed integer, and higher values indicate better signal.
      * The exact units are bearer-dependent. For example, Wi-Fi uses RSSI.
      */
-    private int mSignalStrength;
+    private int mSignalStrength = SIGNAL_STRENGTH_UNSPECIFIED;
 
     /**
      * Sets the signal strength. This is a signed integer, with higher values indicating a stronger
diff --git a/core/java/android/net/NetworkRequest.java b/core/java/android/net/NetworkRequest.java
index 25b1705262..97ded2d73b 100644
--- a/core/java/android/net/NetworkRequest.java
+++ b/core/java/android/net/NetworkRequest.java
@@ -16,6 +16,7 @@
 
 package android.net;
 
+import android.annotation.NonNull;
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.text.TextUtils;
@@ -32,7 +33,7 @@ public class NetworkRequest implements Parcelable {
      * The {@link NetworkCapabilities} that define this request.
      * @hide
      */
-    public final NetworkCapabilities networkCapabilities;
+    public final @NonNull NetworkCapabilities networkCapabilities;
 
     /**
      * Identifies the request.  NetworkRequests should only be constructed by
@@ -307,7 +308,7 @@ public class NetworkRequest implements Parcelable {
         return 0;
     }
     public void writeToParcel(Parcel dest, int flags) {
-        dest.writeParcelable(networkCapabilities, flags);
+        networkCapabilities.writeToParcel(dest, flags);
         dest.writeInt(legacyType);
         dest.writeInt(requestId);
         dest.writeString(type.name());
@@ -315,7 +316,7 @@ public class NetworkRequest implements Parcelable {
     public static final Creator<NetworkRequest> CREATOR =
         new Creator<NetworkRequest>() {
             public NetworkRequest createFromParcel(Parcel in) {
-                NetworkCapabilities nc = (NetworkCapabilities)in.readParcelable(null);
+                NetworkCapabilities nc = NetworkCapabilities.CREATOR.createFromParcel(in);
                 int legacyType = in.readInt();
                 int requestId = in.readInt();
                 Type type = Type.valueOf(in.readString());  // IllegalArgumentException if invalid.
diff --git a/core/java/android/net/NetworkState.java b/core/java/android/net/NetworkState.java
index 95e3802eee..b00cb482e7 100644
--- a/core/java/android/net/NetworkState.java
+++ b/core/java/android/net/NetworkState.java
@@ -18,6 +18,7 @@ package android.net;
 
 import android.os.Parcel;
 import android.os.Parcelable;
+import android.util.Slog;
 
 /**
  * Snapshot of network state.
@@ -43,6 +44,16 @@ public class NetworkState implements Parcelable {
         this.network = network;
         this.subscriberId = subscriberId;
         this.networkId = networkId;
+
+        // This object is an atomic view of a network, so the various components
+        // should always agree on roaming state.
+        if (networkInfo != null && networkCapabilities != null) {
+            if (networkInfo.isRoaming() == networkCapabilities
+                    .hasCapability(NetworkCapabilities.NET_CAPABILITY_NOT_ROAMING)) {
+                Slog.wtf("NetworkState", "Roaming state disagreement between " + networkInfo
+                        + " and " + networkCapabilities);
+            }
+        }
     }
 
     public NetworkState(Parcel in) {