diff --git a/core/java/android/net/OemNetworkPreferences.java b/core/java/android/net/OemNetworkPreferences.java
index 6a8e3f9..5e56164 100644
--- a/core/java/android/net/OemNetworkPreferences.java
+++ b/core/java/android/net/OemNetworkPreferences.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2020 The Android Open Source Project
+ * Copyright (C) 2021 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,14 +18,14 @@
 
 import android.annotation.IntDef;
 import android.annotation.NonNull;
+import android.os.Bundle;
 import android.os.Parcelable;
-import android.util.SparseArray;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
-import java.util.ArrayList;
 import java.util.Collections;
-import java.util.List;
+import java.util.HashMap;
+import java.util.Map;
 import java.util.Objects;
 
 /** @hide */
@@ -60,16 +60,16 @@
     public static final int OEM_NETWORK_PREFERENCE_OEM_PRIVATE_ONLY = 4;
 
     @NonNull
-    private final SparseArray<List<String>> mNetworkMappings;
+    private final Bundle mNetworkMappings;
 
     @NonNull
-    public SparseArray<List<String>> getNetworkPreferences() {
-        return mNetworkMappings.clone();
+    public Map<String, Integer> getNetworkPreferences() {
+        return convertToUnmodifiableMap(mNetworkMappings);
     }
 
-    private OemNetworkPreferences(@NonNull SparseArray<List<String>> networkMappings) {
+    private OemNetworkPreferences(@NonNull final Bundle networkMappings) {
         Objects.requireNonNull(networkMappings);
-        mNetworkMappings = networkMappings.clone();
+        mNetworkMappings = (Bundle) networkMappings.clone();
     }
 
     @Override
@@ -99,26 +99,45 @@
      * @hide
      */
     public static final class Builder {
-        private final SparseArray<List<String>> mNetworkMappings;
+        private final Bundle mNetworkMappings;
 
         public Builder() {
-            mNetworkMappings = new SparseArray<>();
+            mNetworkMappings = new Bundle();
+        }
+
+        public Builder(@NonNull final OemNetworkPreferences preferences) {
+            Objects.requireNonNull(preferences);
+            mNetworkMappings = (Bundle) preferences.mNetworkMappings.clone();
         }
 
         /**
-         * Add a network preference for a list of packages.
+         * Add a network preference for a given package. Previously stored values for the given
+         * package will be overwritten.
          *
-         * @param preference the desired network preference to use
-         * @param packages   full package names (e.g.: "com.google.apps.contacts") for apps to use
-         *                   the given preference
+         * @param packageName full package name (e.g.: "com.google.apps.contacts") of the app
+         *                    to use the given preference
+         * @param preference  the desired network preference to use
          * @return The builder to facilitate chaining.
          */
         @NonNull
-        public Builder addNetworkPreference(@OemNetworkPreference final int preference,
-                @NonNull List<String> packages) {
-            Objects.requireNonNull(packages);
-            mNetworkMappings.put(preference,
-                    Collections.unmodifiableList(new ArrayList<>(packages)));
+        public Builder addNetworkPreference(@NonNull final String packageName,
+                @OemNetworkPreference final int preference) {
+            Objects.requireNonNull(packageName);
+            mNetworkMappings.putInt(packageName, preference);
+            return this;
+        }
+
+        /**
+         * Remove a network preference for a given package.
+         *
+         * @param packageName full package name (e.g.: "com.google.apps.contacts") of the app to
+         *                    remove a preference for.
+         * @return The builder to facilitate chaining.
+         */
+        @NonNull
+        public Builder removeNetworkPreference(@NonNull final String packageName) {
+            Objects.requireNonNull(packageName);
+            mNetworkMappings.remove(packageName);
             return this;
         }
 
@@ -131,6 +150,14 @@
         }
     }
 
+    private static Map<String, Integer> convertToUnmodifiableMap(@NonNull final Bundle bundle) {
+        final Map<String, Integer> networkPreferences = new HashMap<>();
+        for (final String key : bundle.keySet()) {
+            networkPreferences.put(key, bundle.getInt(key));
+        }
+        return Collections.unmodifiableMap(networkPreferences);
+    }
+
     /** @hide */
     @IntDef(prefix = "OEM_NETWORK_PREFERENCE_", value = {
             OEM_NETWORK_PREFERENCE_DEFAULT,
@@ -168,7 +195,7 @@
 
     @Override
     public void writeToParcel(@NonNull android.os.Parcel dest, int flags) {
-        dest.writeSparseArray(mNetworkMappings);
+        dest.writeBundle(mNetworkMappings);
     }
 
     @Override
@@ -187,7 +214,7 @@
                 @Override
                 public OemNetworkPreferences createFromParcel(@NonNull android.os.Parcel in) {
                     return new OemNetworkPreferences(
-                            in.readSparseArray(getClass().getClassLoader()));
+                            in.readBundle(getClass().getClassLoader()));
                 }
             };
 }
diff --git a/framework/src/android/net/ConnectivityManager.java b/framework/src/android/net/ConnectivityManager.java
index 06dec93..fef4152 100644
--- a/framework/src/android/net/ConnectivityManager.java
+++ b/framework/src/android/net/ConnectivityManager.java
@@ -4845,9 +4845,13 @@
         }
     }
 
-    private void setOemNetworkPreference(@NonNull OemNetworkPreferences preference) {
-        Log.d(TAG, "setOemNetworkPreference called with preference: "
-                + preference.toString());
+    private void setOemNetworkPreference(@NonNull final OemNetworkPreferences preference) {
+        try {
+            mService.setOemNetworkPreference(preference);
+        } catch (RemoteException e) {
+            Log.e(TAG, "setOemNetworkPreference() failed for preference: " + preference.toString());
+            throw e.rethrowFromSystemServer();
+        }
     }
 
     @NonNull
diff --git a/framework/src/android/net/IConnectivityManager.aidl b/framework/src/android/net/IConnectivityManager.aidl
index db8b7ed..e2672c4 100644
--- a/framework/src/android/net/IConnectivityManager.aidl
+++ b/framework/src/android/net/IConnectivityManager.aidl
@@ -29,6 +29,7 @@
 import android.net.NetworkInfo;
 import android.net.NetworkRequest;
 import android.net.NetworkState;
+import android.net.OemNetworkPreferences;
 import android.net.ProxyInfo;
 import android.net.UidRange;
 import android.net.QosSocketInfo;
@@ -240,4 +241,6 @@
 
     void registerQosSocketCallback(in QosSocketInfo socketInfo, in IQosCallback callback);
     void unregisterQosCallback(in IQosCallback callback);
+
+    void setOemNetworkPreference(in OemNetworkPreferences preference);
 }
diff --git a/framework/src/android/net/Proxy.java b/framework/src/android/net/Proxy.java
index 03b07e0..9cd7ab2 100644
--- a/framework/src/android/net/Proxy.java
+++ b/framework/src/android/net/Proxy.java
@@ -30,8 +30,6 @@
 import java.net.ProxySelector;
 import java.net.URI;
 import java.util.List;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
 
 /**
  * A convenience class for accessing the user and default proxy
@@ -64,40 +62,9 @@
     @Deprecated
     public static final String EXTRA_PROXY_INFO = "android.intent.extra.PROXY_INFO";
 
-    /** @hide */
-    public static final int PROXY_VALID             = 0;
-    /** @hide */
-    public static final int PROXY_HOSTNAME_EMPTY    = 1;
-    /** @hide */
-    public static final int PROXY_HOSTNAME_INVALID  = 2;
-    /** @hide */
-    public static final int PROXY_PORT_EMPTY        = 3;
-    /** @hide */
-    public static final int PROXY_PORT_INVALID      = 4;
-    /** @hide */
-    public static final int PROXY_EXCLLIST_INVALID  = 5;
-
     private static ConnectivityManager sConnectivityManager = null;
 
-    // Hostname / IP REGEX validation
-    // Matches blank input, ips, and domain names
-    private static final String NAME_IP_REGEX =
-        "[a-zA-Z0-9]+(\\-[a-zA-Z0-9]+)*(\\.[a-zA-Z0-9]+(\\-[a-zA-Z0-9]+)*)*";
-
-    private static final String HOSTNAME_REGEXP = "^$|^" + NAME_IP_REGEX + "$";
-
-    private static final Pattern HOSTNAME_PATTERN;
-
-    private static final String EXCL_REGEX =
-        "[a-zA-Z0-9*]+(\\-[a-zA-Z0-9*]+)*(\\.[a-zA-Z0-9*]+(\\-[a-zA-Z0-9*]+)*)*";
-
-    private static final String EXCLLIST_REGEXP = "^$|^" + EXCL_REGEX + "(," + EXCL_REGEX + ")*$";
-
-    private static final Pattern EXCLLIST_PATTERN;
-
     static {
-        HOSTNAME_PATTERN = Pattern.compile(HOSTNAME_REGEXP);
-        EXCLLIST_PATTERN = Pattern.compile(EXCLLIST_REGEXP);
         sDefaultProxySelector = ProxySelector.getDefault();
     }
 
@@ -216,33 +183,6 @@
         return false;
     }
 
-    /**
-     * Validate syntax of hostname, port and exclusion list entries
-     * {@hide}
-     */
-    public static int validate(String hostname, String port, String exclList) {
-        Matcher match = HOSTNAME_PATTERN.matcher(hostname);
-        Matcher listMatch = EXCLLIST_PATTERN.matcher(exclList);
-
-        if (!match.matches()) return PROXY_HOSTNAME_INVALID;
-
-        if (!listMatch.matches()) return PROXY_EXCLLIST_INVALID;
-
-        if (hostname.length() > 0 && port.length() == 0) return PROXY_PORT_EMPTY;
-
-        if (port.length() > 0) {
-            if (hostname.length() == 0) return PROXY_HOSTNAME_EMPTY;
-            int portVal = -1;
-            try {
-                portVal = Integer.parseInt(port);
-            } catch (NumberFormatException ex) {
-                return PROXY_PORT_INVALID;
-            }
-            if (portVal <= 0 || portVal > 0xFFFF) return PROXY_PORT_INVALID;
-        }
-        return PROXY_VALID;
-    }
-
     /** @hide */
     @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553)
     public static final void setHttpProxySystemProperty(ProxyInfo p) {
diff --git a/framework/src/android/net/ProxyInfo.java b/framework/src/android/net/ProxyInfo.java
index 9c9fed1..229db0d 100644
--- a/framework/src/android/net/ProxyInfo.java
+++ b/framework/src/android/net/ProxyInfo.java
@@ -23,6 +23,8 @@
 import android.os.Parcelable;
 import android.text.TextUtils;
 
+import com.android.net.module.util.ProxyUtils;
+
 import java.net.InetSocketAddress;
 import java.net.URLConnection;
 import java.util.List;
@@ -233,7 +235,7 @@
      */
     public boolean isValid() {
         if (!Uri.EMPTY.equals(mPacFileUrl)) return true;
-        return Proxy.PROXY_VALID == Proxy.validate(mHost == null ? "" : mHost,
+        return ProxyUtils.PROXY_VALID == ProxyUtils.validate(mHost == null ? "" : mHost,
                 mPort == 0 ? "" : Integer.toString(mPort),
                 mExclusionList == null ? "" : mExclusionList);
     }
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index 6789de0..3933e37 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -120,6 +120,7 @@
 import android.net.NetworkTestResultParcelable;
 import android.net.NetworkUtils;
 import android.net.NetworkWatchlistManager;
+import android.net.OemNetworkPreferences;
 import android.net.PrivateDnsConfigParcel;
 import android.net.ProxyInfo;
 import android.net.QosCallbackException;
@@ -281,15 +282,18 @@
     // connect anyway?" dialog after the user selects a network that doesn't validate.
     private static final int PROMPT_UNVALIDATED_DELAY_MS = 8 * 1000;
 
-    // Default to 30s linger time-out. Modifiable only for testing.
+    // Default to 30s linger time-out, and 5s for nascent network. Modifiable only for testing.
     private static final String LINGER_DELAY_PROPERTY = "persist.netmon.linger";
     private static final int DEFAULT_LINGER_DELAY_MS = 30_000;
+    private static final int DEFAULT_NASCENT_DELAY_MS = 5_000;
 
     // The maximum number of network request allowed per uid before an exception is thrown.
     private static final int MAX_NETWORK_REQUESTS_PER_UID = 100;
 
     @VisibleForTesting
     protected int mLingerDelayMs;  // Can't be final, or test subclass constructors can't change it.
+    @VisibleForTesting
+    protected int mNascentDelayMs;
 
     // How long to delay to removal of a pending intent based request.
     // See Settings.Secure.CONNECTIVITY_RELEASE_PENDING_INTENT_DELAY_MS
@@ -1063,6 +1067,8 @@
                 Settings.Secure.CONNECTIVITY_RELEASE_PENDING_INTENT_DELAY_MS, 5_000);
 
         mLingerDelayMs = mSystemProperties.getInt(LINGER_DELAY_PROPERTY, DEFAULT_LINGER_DELAY_MS);
+        // TODO: Consider making the timer customizable.
+        mNascentDelayMs = DEFAULT_NASCENT_DELAY_MS;
 
         mNMS = Objects.requireNonNull(netManager, "missing INetworkManagementService");
         mStatsService = Objects.requireNonNull(statsService, "missing INetworkStatsService");
@@ -2030,7 +2036,7 @@
                 mHandler.sendMessage(mHandler.obtainMessage(
                         EVENT_PRIVATE_DNS_VALIDATION_UPDATE,
                         new PrivateDnsValidationUpdate(netId,
-                                InetAddress.parseNumericAddress(ipAddress),
+                                InetAddresses.parseNumericAddress(ipAddress),
                                 hostname, validated)));
             } catch (IllegalArgumentException e) {
                 loge("Error parsing ip address in validation event");
@@ -3334,7 +3340,7 @@
         // 3. If this network is unneeded (which implies it is not lingering), and there is at least
         //    one lingered request, set inactive.
         nai.updateInactivityTimer();
-        if (nai.isLingering() && nai.numForegroundNetworkRequests() > 0) {
+        if (nai.isInactive() && nai.numForegroundNetworkRequests() > 0) {
             if (DBG) log("Unsetting inactive " + nai.toShortString());
             nai.unsetInactive();
             logNetworkEvent(nai, NetworkEvent.NETWORK_UNLINGER);
@@ -3628,7 +3634,7 @@
                 return true;
         }
 
-        if (!nai.everConnected || nai.isVPN() || nai.isLingering() || numRequests > 0) {
+        if (!nai.everConnected || nai.isVPN() || nai.isInactive() || numRequests > 0) {
             return false;
         }
         for (NetworkRequestInfo nri : mNetworkRequests.values()) {
@@ -7241,7 +7247,7 @@
             // Tear the network down.
             teardownUnneededNetwork(oldNetwork);
         } else {
-            // Put the network in the background.
+            // Put the network in the background if it doesn't satisfy any foreground request.
             updateCapabilitiesForNetwork(oldNetwork);
         }
     }
@@ -7495,6 +7501,14 @@
             } else {
                 if (VDBG || DDBG) log("   accepting network in place of null");
             }
+
+            // To prevent constantly CPU wake up for nascent timer, if a network comes up
+            // and immediately satisfies a request then remove the timer. This will happen for
+            // all networks except in the case of an underlying network for a VCN.
+            if (newSatisfier.isNascent()) {
+                newSatisfier.unlingerRequest(NetworkRequest.REQUEST_ID_NONE);
+            }
+
             newSatisfier.unlingerRequest(newRequest.requestId);
             if (!newSatisfier.addRequest(newRequest)) {
                 Log.wtf(TAG, "BUG: " + newSatisfier.toShortString() + " already has "
@@ -7637,19 +7651,19 @@
             }
         }
 
-        // Update the linger state before processing listen callbacks, because the background
-        // computation depends on whether the network is lingering. Don't send the LOSING callbacks
+        // Update the inactivity state before processing listen callbacks, because the background
+        // computation depends on whether the network is inactive. Don't send the LOSING callbacks
         // just yet though, because they have to be sent after the listens are processed to keep
         // backward compatibility.
-        final ArrayList<NetworkAgentInfo> lingeredNetworks = new ArrayList<>();
+        final ArrayList<NetworkAgentInfo> inactiveNetworks = new ArrayList<>();
         for (final NetworkAgentInfo nai : nais) {
-            // Rematching may have altered the linger state of some networks, so update all linger
-            // timers. updateLingerState reads the state from the network agent and does nothing
-            // if the state has not changed : the source of truth is controlled with
-            // NetworkAgentInfo#lingerRequest and NetworkAgentInfo#unlingerRequest, which have been
-            // called while rematching the individual networks above.
+            // Rematching may have altered the inactivity state of some networks, so update all
+            // inactivity timers. updateInactivityState reads the state from the network agent
+            // and does nothing if the state has not changed : the source of truth is controlled
+            // with NetworkAgentInfo#lingerRequest and NetworkAgentInfo#unlingerRequest, which
+            // have been called while rematching the individual networks above.
             if (updateInactivityState(nai, now)) {
-                lingeredNetworks.add(nai);
+                inactiveNetworks.add(nai);
             }
         }
 
@@ -7666,7 +7680,11 @@
             processNewlySatisfiedListenRequests(nai);
         }
 
-        for (final NetworkAgentInfo nai : lingeredNetworks) {
+        for (final NetworkAgentInfo nai : inactiveNetworks) {
+            // For nascent networks, if connecting with no foreground request, skip broadcasting
+            // LOSING for backward compatibility. This is typical when mobile data connected while
+            // wifi connected with mobile data always-on enabled.
+            if (nai.isNascent()) continue;
             notifyNetworkLosing(nai, now);
         }
 
@@ -7907,6 +7925,15 @@
             // doing.
             updateSignalStrengthThresholds(networkAgent, "CONNECT", null);
 
+            // Before first rematching networks, put an inactivity timer without any request, this
+            // allows {@code updateInactivityState} to update the state accordingly and prevent
+            // tearing down for any {@code unneeded} evaluation in this period.
+            // Note that the timer will not be rescheduled since the expiry time is
+            // fixed after connection regardless of the network satisfying other requests or not.
+            // But it will be removed as soon as the network satisfies a request for the first time.
+            networkAgent.lingerRequest(NetworkRequest.REQUEST_ID_NONE,
+                    SystemClock.elapsedRealtime(), mNascentDelayMs);
+
             // Consider network even though it is not yet validated.
             rematchAllNetworksAndRequests();
 
@@ -9097,6 +9124,7 @@
             }
         }
     }
+
     /**
      * Registers {@link QosSocketFilter} with {@link IQosCallback}.
      *
@@ -9146,4 +9174,10 @@
     public void unregisterQosCallback(@NonNull final IQosCallback callback) {
         mQosCallbackTracker.unregisterCallback(callback);
     }
+
+    @Override
+    public void setOemNetworkPreference(@NonNull final OemNetworkPreferences preference) {
+        // TODO http://b/176495594 track multiple default networks with networkPreferences
+        if (DBG) log("setOemNetworkPreference() called with: " + preference.toString());
+    }
 }
diff --git a/services/core/java/com/android/server/TestNetworkService.java b/services/core/java/com/android/server/TestNetworkService.java
index e96fd39..96f832d 100644
--- a/services/core/java/com/android/server/TestNetworkService.java
+++ b/services/core/java/com/android/server/TestNetworkService.java
@@ -50,6 +50,7 @@
 import com.android.internal.annotations.GuardedBy;
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.net.module.util.NetdUtils;
+import com.android.net.module.util.NetworkStackConstants;
 
 import java.io.UncheckedIOException;
 import java.net.Inet4Address;
@@ -280,10 +281,12 @@
 
         // Add global routes (but as non-default, non-internet providing network)
         if (allowIPv4) {
-            lp.addRoute(new RouteInfo(new IpPrefix(Inet4Address.ANY, 0), null, iface));
+            lp.addRoute(new RouteInfo(new IpPrefix(
+                    NetworkStackConstants.IPV4_ADDR_ANY, 0), null, iface));
         }
         if (allowIPv6) {
-            lp.addRoute(new RouteInfo(new IpPrefix(Inet6Address.ANY, 0), null, iface));
+            lp.addRoute(new RouteInfo(new IpPrefix(
+                    NetworkStackConstants.IPV6_ADDR_ANY, 0), null, iface));
         }
 
         final TestNetworkAgent agent = new TestNetworkAgent(context, looper, nc, lp,
diff --git a/services/core/java/com/android/server/connectivity/DnsManager.java b/services/core/java/com/android/server/connectivity/DnsManager.java
index c70bb08..43d9ade 100644
--- a/services/core/java/com/android/server/connectivity/DnsManager.java
+++ b/services/core/java/com/android/server/connectivity/DnsManager.java
@@ -32,6 +32,7 @@
 import android.content.Context;
 import android.content.Intent;
 import android.net.IDnsResolver;
+import android.net.InetAddresses;
 import android.net.LinkProperties;
 import android.net.Network;
 import android.net.ResolverOptionsParcel;
@@ -190,7 +191,7 @@
             for (String ipAddress : ipAddresses) {
                 try {
                     latestDnses.add(new Pair(hostname,
-                            InetAddress.parseNumericAddress(ipAddress)));
+                            InetAddresses.parseNumericAddress(ipAddress)));
                 } catch (IllegalArgumentException e) {}
             }
             // Remove <hostname, ipAddress> pairs that should not be tracked.
diff --git a/services/core/java/com/android/server/connectivity/Nat464Xlat.java b/services/core/java/com/android/server/connectivity/Nat464Xlat.java
index 952193b..46c49e7 100644
--- a/services/core/java/com/android/server/connectivity/Nat464Xlat.java
+++ b/services/core/java/com/android/server/connectivity/Nat464Xlat.java
@@ -34,9 +34,9 @@
 
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.util.ArrayUtils;
+import com.android.net.module.util.NetworkStackConstants;
 import com.android.server.net.BaseNetworkObserver;
 
-import java.net.Inet4Address;
 import java.net.Inet6Address;
 import java.util.Objects;
 
@@ -433,7 +433,7 @@
         // clat IPv4 address itself (for those apps, it doesn't matter what
         // the IP of the gateway is, only that there is one).
         RouteInfo ipv4Default = new RouteInfo(
-                new LinkAddress(Inet4Address.ANY, 0),
+                new LinkAddress(NetworkStackConstants.IPV4_ADDR_ANY, 0),
                 clatAddress.getAddress(), mIface);
         stacked.addRoute(ipv4Default);
         stacked.addLinkAddress(clatAddress);
diff --git a/services/core/java/com/android/server/connectivity/NetworkAgentInfo.java b/services/core/java/com/android/server/connectivity/NetworkAgentInfo.java
index a9a705f..bff1a5c 100644
--- a/services/core/java/com/android/server/connectivity/NetworkAgentInfo.java
+++ b/services/core/java/com/android/server/connectivity/NetworkAgentInfo.java
@@ -122,6 +122,13 @@
 //
 // When ConnectivityService disconnects a network:
 // -----------------------------------------------
+// If a network is just connected, ConnectivityService will think it will be used soon, but might
+// not be used. Thus, a 5s timer will be held to prevent the network being torn down immediately.
+// This "nascent" state is implemented by the "lingering" logic below without relating to any
+// request, and is used in some cases where network requests race with network establishment. The
+// nascent state ends when the 5-second timer fires, or as soon as the network satisfies a
+// request, whichever is earlier. In this state, the network is considered in the background.
+//
 // If a network has no chance of satisfying any requests (even if it were to become validated
 // and enter state #5), ConnectivityService will disconnect the NetworkAgent's AsyncChannel.
 //
@@ -271,7 +278,8 @@
 
     // All inactivity timers for this network, sorted by expiry time. A timer is added whenever
     // a request is moved to a network with a better score, regardless of whether the network is or
-    // was lingering or not.
+    // was lingering or not. An inactivity timer is also added when a network connects
+    // without immediately satisfying any requests.
     // TODO: determine if we can replace this with a smaller or unsorted data structure. (e.g.,
     // SparseLongArray) combined with the timestamp of when the last timer is scheduled to fire.
     private final SortedSet<InactivityTimer> mInactivityTimers = new TreeSet<>();
@@ -896,7 +904,12 @@
 
     /**
      * Sets the specified requestId to linger on this network for the specified time. Called by
-     * ConnectivityService when the request is moved to another network with a higher score.
+     * ConnectivityService when the request is moved to another network with a higher score, or
+     * when a network is newly created.
+     *
+     * @param requestId The requestId of the request that no longer need to be served by this
+     *                  network. Or {@link NetworkRequest.REQUEST_ID_NONE} if this is the
+     *                  {@code LingerTimer} for a newly created network.
      */
     public void lingerRequest(int requestId, long now, long duration) {
         if (mInactivityTimerForRequest.get(requestId) != null) {
@@ -969,10 +982,23 @@
         mInactive = false;
     }
 
-    public boolean isLingering() {
+    public boolean isInactive() {
         return mInactive;
     }
 
+    public boolean isLingering() {
+        return mInactive && !isNascent();
+    }
+
+    /**
+     * Return whether the network is just connected and about to be torn down because of not
+     * satisfying any request.
+     */
+    public boolean isNascent() {
+        return mInactive && mInactivityTimers.size() == 1
+                && mInactivityTimers.first().requestId == NetworkRequest.REQUEST_ID_NONE;
+    }
+
     public void clearInactivityState() {
         if (mInactivityMessage != null) {
             mInactivityMessage.cancel();
@@ -1022,7 +1048,7 @@
                 + "network{" + network + "}  handle{" + network.getNetworkHandle() + "}  ni{"
                 + networkInfo.toShortString() + "} "
                 + "  Score{" + getCurrentScore() + "} "
-                + (isLingering() ? " lingering" : "")
+                + (isNascent() ? " nascent" : (isLingering() ? " lingering" : ""))
                 + (everValidated ? " everValidated" : "")
                 + (lastValidated ? " lastValidated" : "")
                 + (partialConnectivity ? " partialConnectivity" : "")
diff --git a/services/core/java/com/android/server/connectivity/PermissionMonitor.java b/services/core/java/com/android/server/connectivity/PermissionMonitor.java
index d507b5f..8d21f6f 100644
--- a/services/core/java/com/android/server/connectivity/PermissionMonitor.java
+++ b/services/core/java/com/android/server/connectivity/PermissionMonitor.java
@@ -265,7 +265,10 @@
         for (Entry<Integer, Boolean> app : apps.entrySet()) {
             List<Integer> list = app.getValue() ? system : network;
             for (int user : users) {
-                list.add(UserHandle.getUid(user, app.getKey()));
+                final UserHandle handle = UserHandle.of(user);
+                if (handle == null) continue;
+
+                list.add(UserHandle.getUid(handle, app.getKey()));
             }
         }
         try {
@@ -550,7 +553,10 @@
         for (UidRange range : ranges) {
             for (int userId = range.getStartUser(); userId <= range.getEndUser(); userId++) {
                 for (int appId : appIds) {
-                    final int uid = UserHandle.getUid(userId, appId);
+                    final UserHandle handle = UserHandle.of(userId);
+                    if (handle == null) continue;
+
+                    final int uid = UserHandle.getUid(handle, appId);
                     if (range.contains(uid)) {
                         result.add(uid);
                     }
diff --git a/tests/net/common/java/android/net/OemNetworkPreferencesTest.java b/tests/net/common/java/android/net/OemNetworkPreferencesTest.java
index cade5ba..d232a50 100644
--- a/tests/net/common/java/android/net/OemNetworkPreferencesTest.java
+++ b/tests/net/common/java/android/net/OemNetworkPreferencesTest.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2020 The Android Open Source Project
+ * Copyright (C) 2021 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,22 +20,20 @@
 import static com.android.testutils.ParcelUtils.assertParcelSane;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
 import android.os.Build;
-import android.util.SparseArray;
 
 import androidx.test.filters.SmallTest;
 
 import com.android.testutils.DevSdkIgnoreRule.IgnoreUpTo;
 import com.android.testutils.DevSdkIgnoreRunner;
 
-import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
-import java.util.ArrayList;
-import java.util.List;
+import java.util.Map;
 
 @IgnoreUpTo(Build.VERSION_CODES.R)
 @RunWith(DevSdkIgnoreRunner.class)
@@ -45,51 +43,51 @@
     private static final int TEST_PREF = OemNetworkPreferences.OEM_NETWORK_PREFERENCE_DEFAULT;
     private static final String TEST_PACKAGE = "com.google.apps.contacts";
 
-    private final List<String> mPackages = new ArrayList<>();
     private final OemNetworkPreferences.Builder mBuilder = new OemNetworkPreferences.Builder();
 
-    @Before
-    public void beforeEachTestMethod() {
-        mPackages.add(TEST_PACKAGE);
-    }
-
     @Test
-    public void builderAddNetworkPreferenceRequiresNonNullPackages() {
+    public void testBuilderAddNetworkPreferenceRequiresNonNullPackageName() {
         assertThrows(NullPointerException.class,
-                () -> mBuilder.addNetworkPreference(TEST_PREF, null));
+                () -> mBuilder.addNetworkPreference(null, TEST_PREF));
     }
 
     @Test
-    public void getNetworkPreferencesReturnsCorrectValue() {
-        final int expectedNumberOfMappings = 1;
-        mBuilder.addNetworkPreference(TEST_PREF, mPackages);
+    public void testBuilderRemoveNetworkPreferenceRequiresNonNullPackageName() {
+        assertThrows(NullPointerException.class,
+                () -> mBuilder.removeNetworkPreference(null));
+    }
 
-        final SparseArray<List<String>> networkPreferences =
+    @Test
+    public void testGetNetworkPreferenceReturnsCorrectValue() {
+        final int expectedNumberOfMappings = 1;
+        mBuilder.addNetworkPreference(TEST_PACKAGE, TEST_PREF);
+
+        final Map<String, Integer> networkPreferences =
                 mBuilder.build().getNetworkPreferences();
 
         assertEquals(expectedNumberOfMappings, networkPreferences.size());
-        assertEquals(mPackages.size(), networkPreferences.get(TEST_PREF).size());
-        assertEquals(mPackages.get(0), networkPreferences.get(TEST_PREF).get(0));
+        assertTrue(networkPreferences.containsKey(TEST_PACKAGE));
     }
 
     @Test
-    public void getNetworkPreferencesReturnsUnmodifiableValue() {
+    public void testGetNetworkPreferenceReturnsUnmodifiableValue() {
         final String newPackage = "new.com.google.apps.contacts";
-        mBuilder.addNetworkPreference(TEST_PREF, mPackages);
+        mBuilder.addNetworkPreference(TEST_PACKAGE, TEST_PREF);
 
-        final SparseArray<List<String>> networkPreferences =
+        final Map<String, Integer> networkPreferences =
                 mBuilder.build().getNetworkPreferences();
 
         assertThrows(UnsupportedOperationException.class,
-                () -> networkPreferences.get(TEST_PREF).set(mPackages.size() - 1, newPackage));
+                () -> networkPreferences.put(newPackage, TEST_PREF));
 
         assertThrows(UnsupportedOperationException.class,
-                () -> networkPreferences.get(TEST_PREF).add(newPackage));
+                () -> networkPreferences.remove(TEST_PACKAGE));
+
     }
 
     @Test
-    public void toStringReturnsCorrectValue() {
-        mBuilder.addNetworkPreference(TEST_PREF, mPackages);
+    public void testToStringReturnsCorrectValue() {
+        mBuilder.addNetworkPreference(TEST_PACKAGE, TEST_PREF);
 
         final String networkPreferencesString = mBuilder.build().getNetworkPreferences().toString();
 
@@ -99,10 +97,56 @@
 
     @Test
     public void testOemNetworkPreferencesParcelable() {
-        mBuilder.addNetworkPreference(TEST_PREF, mPackages);
+        mBuilder.addNetworkPreference(TEST_PACKAGE, TEST_PREF);
 
         final OemNetworkPreferences prefs = mBuilder.build();
 
         assertParcelSane(prefs, 1 /* fieldCount */);
     }
+
+    @Test
+    public void testAddNetworkPreferenceOverwritesPriorPreference() {
+        final int newPref = OemNetworkPreferences.OEM_NETWORK_PREFERENCE_OEM_PAID;
+        mBuilder.addNetworkPreference(TEST_PACKAGE, TEST_PREF);
+        Map<String, Integer> networkPreferences =
+                mBuilder.build().getNetworkPreferences();
+
+        assertTrue(networkPreferences.containsKey(TEST_PACKAGE));
+        assertEquals(networkPreferences.get(TEST_PACKAGE).intValue(), TEST_PREF);
+
+        mBuilder.addNetworkPreference(TEST_PACKAGE, newPref);
+        networkPreferences = mBuilder.build().getNetworkPreferences();
+
+        assertTrue(networkPreferences.containsKey(TEST_PACKAGE));
+        assertEquals(networkPreferences.get(TEST_PACKAGE).intValue(), newPref);
+    }
+
+    @Test
+    public void testRemoveNetworkPreferenceRemovesValue() {
+        mBuilder.addNetworkPreference(TEST_PACKAGE, TEST_PREF);
+        Map<String, Integer> networkPreferences =
+                mBuilder.build().getNetworkPreferences();
+
+        assertTrue(networkPreferences.containsKey(TEST_PACKAGE));
+
+        mBuilder.removeNetworkPreference(TEST_PACKAGE);
+        networkPreferences = mBuilder.build().getNetworkPreferences();
+
+        assertFalse(networkPreferences.containsKey(TEST_PACKAGE));
+    }
+
+    @Test
+    public void testConstructorByOemNetworkPreferencesSetsValue() {
+        mBuilder.addNetworkPreference(TEST_PACKAGE, TEST_PREF);
+        OemNetworkPreferences networkPreference = mBuilder.build();
+
+        final Map<String, Integer> networkPreferences =
+                new OemNetworkPreferences
+                        .Builder(networkPreference)
+                        .build()
+                        .getNetworkPreferences();
+
+        assertTrue(networkPreferences.containsKey(TEST_PACKAGE));
+        assertEquals(networkPreferences.get(TEST_PACKAGE).intValue(), TEST_PREF);
+    }
 }
diff --git a/tests/net/java/com/android/server/ConnectivityServiceTest.java b/tests/net/java/com/android/server/ConnectivityServiceTest.java
index 024e6e3..fe19f86 100644
--- a/tests/net/java/com/android/server/ConnectivityServiceTest.java
+++ b/tests/net/java/com/android/server/ConnectivityServiceTest.java
@@ -331,11 +331,12 @@
     private static final String TAG = "ConnectivityServiceTest";
 
     private static final int TIMEOUT_MS = 500;
-    private static final int TEST_LINGER_DELAY_MS = 300;
-    // Chosen to be less than the linger timeout. This ensures that we can distinguish between a
-    // LOST callback that arrives immediately and a LOST callback that arrives after the linger
-    // timeout. For this, our assertions should run fast enough to leave less than
-    // (mService.mLingerDelayMs - TEST_CALLBACK_TIMEOUT_MS) between the time callbacks are
+    private static final int TEST_LINGER_DELAY_MS = 400;
+    private static final int TEST_NASCENT_DELAY_MS = 300;
+    // Chosen to be less than the linger and nascent timeout. This ensures that we can distinguish
+    // between a LOST callback that arrives immediately and a LOST callback that arrives after
+    // the linger/nascent timeout. For this, our assertions should run fast enough to leave
+    // less than (mService.mLingerDelayMs - TEST_CALLBACK_TIMEOUT_MS) between the time callbacks are
     // supposedly fired, and the time we call expectCallback.
     private static final int TEST_CALLBACK_TIMEOUT_MS = 250;
     // Chosen to be less than TEST_CALLBACK_TIMEOUT_MS. This ensures that requests have time to
@@ -1402,6 +1403,7 @@
                 mMockNetd,
                 mDeps);
         mService.mLingerDelayMs = TEST_LINGER_DELAY_MS;
+        mService.mNascentDelayMs = TEST_NASCENT_DELAY_MS;
         verify(mDeps).makeMultinetworkPolicyTracker(any(), any(), any());
 
         final ArgumentCaptor<INetworkPolicyListener> policyListenerCaptor =
@@ -1744,6 +1746,108 @@
         verifyNoNetwork();
     }
 
+    /**
+     * Verify a newly created network will be inactive instead of torn down even if no one is
+     * requesting.
+     */
+    @Test
+    public void testNewNetworkInactive() throws Exception {
+        // Create a callback that monitoring the testing network.
+        final TestNetworkCallback listenCallback = new TestNetworkCallback();
+        mCm.registerNetworkCallback(new NetworkRequest.Builder().build(), listenCallback);
+
+        // 1. Create a network that is not requested by anyone, and does not satisfy any of the
+        // default requests. Verify that the network will be inactive instead of torn down.
+        mWiFiNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_WIFI);
+        mWiFiNetworkAgent.connectWithoutInternet();
+        listenCallback.expectAvailableCallbacksUnvalidated(mWiFiNetworkAgent);
+        listenCallback.assertNoCallback();
+
+        // Verify that the network will be torn down after nascent expiry. A small period of time
+        // is added in case of flakiness.
+        final int nascentTimeoutMs =
+                mService.mNascentDelayMs + mService.mNascentDelayMs / 4;
+        listenCallback.expectCallback(CallbackEntry.LOST, mWiFiNetworkAgent, nascentTimeoutMs);
+
+        // 2. Create a network that is satisfied by a request comes later.
+        mWiFiNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_WIFI);
+        mWiFiNetworkAgent.connectWithoutInternet();
+        listenCallback.expectAvailableCallbacksUnvalidated(mWiFiNetworkAgent);
+        final NetworkRequest wifiRequest = new NetworkRequest.Builder()
+                .addTransportType(TRANSPORT_WIFI).build();
+        final TestNetworkCallback wifiCallback = new TestNetworkCallback();
+        mCm.requestNetwork(wifiRequest, wifiCallback);
+        wifiCallback.expectAvailableCallbacksUnvalidated(mWiFiNetworkAgent);
+
+        // Verify that the network will be kept since the request is still satisfied. And is able
+        // to get disconnected as usual if the request is released after the nascent timer expires.
+        listenCallback.assertNoCallback(nascentTimeoutMs);
+        mCm.unregisterNetworkCallback(wifiCallback);
+        listenCallback.expectCallback(CallbackEntry.LOST, mWiFiNetworkAgent);
+
+        // 3. Create a network that is satisfied by a request comes later.
+        mWiFiNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_WIFI);
+        mWiFiNetworkAgent.connectWithoutInternet();
+        listenCallback.expectAvailableCallbacksUnvalidated(mWiFiNetworkAgent);
+        mCm.requestNetwork(wifiRequest, wifiCallback);
+        wifiCallback.expectAvailableCallbacksUnvalidated(mWiFiNetworkAgent);
+
+        // Verify that the network will still be torn down after the request gets removed.
+        mCm.unregisterNetworkCallback(wifiCallback);
+        listenCallback.expectCallback(CallbackEntry.LOST, mWiFiNetworkAgent);
+
+        // There is no need to ensure that LOSING is never sent in the common case that the
+        // network immediately satisfies a request that was already present, because it is already
+        // verified anywhere whenever {@code TestNetworkCallback#expectAvailable*} is called.
+
+        mCm.unregisterNetworkCallback(listenCallback);
+    }
+
+    /**
+     * Verify a newly created network will be inactive and switch to background if only background
+     * request is satisfied.
+     */
+    @Test
+    public void testNewNetworkInactive_bgNetwork() throws Exception {
+        // Create a callback that monitoring the wifi network.
+        final TestNetworkCallback wifiListenCallback = new TestNetworkCallback();
+        mCm.registerNetworkCallback(new NetworkRequest.Builder()
+                .addTransportType(TRANSPORT_WIFI).build(), wifiListenCallback);
+
+        // Create callbacks that can monitor background and foreground mobile networks.
+        // This is done by granting using background networks permission before registration. Thus,
+        // the service will not add {@code NET_CAPABILITY_FOREGROUND} by default.
+        grantUsingBackgroundNetworksPermissionForUid(Binder.getCallingUid());
+        final TestNetworkCallback bgMobileListenCallback = new TestNetworkCallback();
+        final TestNetworkCallback fgMobileListenCallback = new TestNetworkCallback();
+        mCm.registerNetworkCallback(new NetworkRequest.Builder()
+                .addTransportType(TRANSPORT_CELLULAR).build(), bgMobileListenCallback);
+        mCm.registerNetworkCallback(new NetworkRequest.Builder()
+                .addTransportType(TRANSPORT_CELLULAR)
+                .addCapability(NET_CAPABILITY_FOREGROUND).build(), fgMobileListenCallback);
+
+        // Connect wifi, which satisfies default request.
+        mWiFiNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_WIFI);
+        mWiFiNetworkAgent.connect(true);
+        wifiListenCallback.expectAvailableThenValidatedCallbacks(mWiFiNetworkAgent);
+
+        // Connect a cellular network, verify that satisfies only the background callback.
+        setAlwaysOnNetworks(true);
+        mCellNetworkAgent = new TestNetworkAgentWrapper(TRANSPORT_CELLULAR);
+        mCellNetworkAgent.connect(true);
+        bgMobileListenCallback.expectAvailableThenValidatedCallbacks(mCellNetworkAgent);
+        fgMobileListenCallback.assertNoCallback();
+        assertFalse(isForegroundNetwork(mCellNetworkAgent));
+
+        mCellNetworkAgent.disconnect();
+        bgMobileListenCallback.expectCallback(CallbackEntry.LOST, mCellNetworkAgent);
+        fgMobileListenCallback.assertNoCallback();
+
+        mCm.unregisterNetworkCallback(wifiListenCallback);
+        mCm.unregisterNetworkCallback(bgMobileListenCallback);
+        mCm.unregisterNetworkCallback(fgMobileListenCallback);
+    }
+
     @Test
     public void testValidatedCellularOutscoresUnvalidatedWiFi() throws Exception {
         // Test bringing up unvalidated WiFi
@@ -3901,8 +4005,9 @@
             setAlwaysOnNetworks(false);
             testFactory.expectRequestRemove();
 
-            // ...  and cell data to be torn down.
-            cellNetworkCallback.expectCallback(CallbackEntry.LOST, mCellNetworkAgent);
+            // ...  and cell data to be torn down after nascent network timeout.
+            cellNetworkCallback.expectCallback(CallbackEntry.LOST, mCellNetworkAgent,
+                    mService.mNascentDelayMs + TEST_CALLBACK_TIMEOUT_MS);
             assertLength(1, mCm.getAllNetworks());
         } finally {
             testFactory.terminate();