diff --git a/Tethering/tests/integration/base/android/net/EthernetTetheringTestBase.java b/Tethering/tests/integration/base/android/net/EthernetTetheringTestBase.java
index aac71a0..c232697 100644
--- a/Tethering/tests/integration/base/android/net/EthernetTetheringTestBase.java
+++ b/Tethering/tests/integration/base/android/net/EthernetTetheringTestBase.java
@@ -57,8 +57,6 @@
 import android.net.TetheringManager.TetheringRequest;
 import android.net.TetheringTester.TetheredDevice;
 import android.net.cts.util.CtsNetUtils;
-import android.net.cts.util.CtsTetheringUtils;
-import android.net.cts.util.CtsTetheringUtils.TestTetheringEventCallback;
 import android.os.Handler;
 import android.os.HandlerThread;
 import android.os.SystemClock;
@@ -172,18 +170,24 @@
         // Tethering would cache the last upstreams so that the next enabled tethering avoids
         // picking up the address that is in conflict with the upstreams. To protect subsequent
         // tests, turn tethering on and off before running them.
-        final CtsTetheringUtils utils = new CtsTetheringUtils(sContext);
-        final TestTetheringEventCallback callback = utils.registerTetheringEventCallback();
+        MyTetheringEventCallback callback = null;
+        TestNetworkInterface testIface = null;
         try {
-            if (!callback.isWifiTetheringSupported(sContext)) return;
+            // If the physical ethernet interface is available, do nothing.
+            if (isInterfaceForTetheringAvailable()) return;
 
-            callback.expectNoTetheringActive();
+            testIface = createTestInterface();
+            setIncludeTestInterfaces(true);
 
-            utils.startWifiTethering(callback);
-            callback.getCurrentValidUpstream();
-            utils.stopWifiTethering(callback);
+            callback = enableEthernetTethering(testIface.getInterfaceName(), null);
+            callback.awaitUpstreamChanged(true /* throwTimeoutException */);
+        } catch (TimeoutException e) {
+            Log.d(TAG, "WARNNING " + e);
         } finally {
-            utils.unregisterTetheringEventCallback(callback);
+            maybeCloseTestInterface(testIface);
+            maybeUnregisterTetheringEventCallback(callback);
+
+            setIncludeTestInterfaces(false);
         }
     }
 
@@ -213,7 +217,7 @@
         }
     }
 
-    protected void maybeCloseTestInterface(final TestNetworkInterface testInterface)
+    protected static void maybeCloseTestInterface(final TestNetworkInterface testInterface)
             throws Exception {
         if (testInterface != null) {
             testInterface.getFileDescriptor().close();
@@ -221,8 +225,8 @@
         }
     }
 
-    protected void maybeUnregisterTetheringEventCallback(final MyTetheringEventCallback callback)
-            throws Exception {
+    protected static void maybeUnregisterTetheringEventCallback(
+            final MyTetheringEventCallback callback) throws Exception {
         if (callback != null) {
             callback.awaitInterfaceUntethered();
             callback.unregister();
@@ -307,13 +311,13 @@
         }
     }
 
-    protected void setIncludeTestInterfaces(boolean include) {
+    protected static void setIncludeTestInterfaces(boolean include) {
         runAsShell(NETWORK_SETTINGS, () -> {
             sEm.setIncludeTestInterfaces(include);
         });
     }
 
-    protected void setPreferTestNetworks(boolean prefer) {
+    protected static void setPreferTestNetworks(boolean prefer) {
         runAsShell(NETWORK_SETTINGS, () -> {
             sTm.setPreferTestNetworks(prefer);
         });
@@ -355,7 +359,7 @@
         private final TetheringInterface mIface;
         private final Network mExpectedUpstream;
 
-        private boolean mAcceptAnyUpstream = false;
+        private final boolean mAcceptAnyUpstream;
 
         private volatile boolean mInterfaceWasTethered = false;
         private volatile boolean mInterfaceWasLocalOnly = false;
@@ -369,13 +373,16 @@
         private static final int EXPANDED_TIMEOUT_MS = 30000;
 
         MyTetheringEventCallback(String iface) {
-            this(iface, null);
+            mIface = new TetheringInterface(TETHERING_ETHERNET, iface);
+            mExpectedUpstream = null;
             mAcceptAnyUpstream = true;
         }
 
-        MyTetheringEventCallback(String iface, Network expectedUpstream) {
+        MyTetheringEventCallback(String iface, @NonNull Network expectedUpstream) {
+            Objects.requireNonNull(expectedUpstream);
             mIface = new TetheringInterface(TETHERING_ETHERNET, iface);
             mExpectedUpstream = expectedUpstream;
+            mAcceptAnyUpstream = false;
         }
 
         public void unregister() {
@@ -503,6 +510,11 @@
 
             Log.d(TAG, "Got upstream changed: " + network);
             mUpstream = network;
+            // The callback always updates the current tethering status when it's first registered.
+            // If the caller registers the callback before tethering starts, the null upstream
+            // would be updated. Filtering out the null case because it's not a valid upstream that
+            // we care about.
+            if (mUpstream == null) return;
             if (mAcceptAnyUpstream || Objects.equals(mUpstream, mExpectedUpstream)) {
                 mUpstreamLatch.countDown();
             }
@@ -643,7 +655,7 @@
         }
     }
 
-    protected TestNetworkInterface createTestInterface() throws Exception {
+    protected static TestNetworkInterface createTestInterface() throws Exception {
         TestNetworkManager tnm = runAsShell(MANAGE_TEST_NETWORKS, () ->
                 sContext.getSystemService(TestNetworkManager.class));
         TestNetworkInterface iface = runAsShell(MANAGE_TEST_NETWORKS, () ->