diff --git a/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeSessionDigitalSignatureTest.java b/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeSessionDigitalSignatureTest.java
new file mode 100644
index 0000000..ebf8a41
--- /dev/null
+++ b/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeSessionDigitalSignatureTest.java
@@ -0,0 +1,210 @@
+/*
+ * Copyright (C) 2020 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.ipsec.ike.cts;
+
+import android.net.InetAddresses;
+import android.net.LinkAddress;
+import android.net.ipsec.ike.IkeDerAsn1DnIdentification;
+import android.net.ipsec.ike.IkeSession;
+import android.net.ipsec.ike.IkeSessionParams;
+import android.net.ipsec.ike.IkeTrafficSelector;
+
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import com.android.internal.net.ipsec.ike.testutils.CertUtils;
+
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.net.InetAddress;
+import java.security.cert.X509Certificate;
+import java.security.interfaces.RSAPrivateKey;
+import java.util.ArrayList;
+import java.util.Arrays;
+
+import javax.security.auth.x500.X500Principal;
+
+/**
+ * Explicitly test setting up transport mode Child SA so that devices do not have
+ * FEATURE_IPSEC_TUNNELS will be test covered. Tunnel mode Child SA setup has been tested in
+ * IkeSessionPskTest and authentication method is orthogonal to Child mode.
+ */
+@RunWith(AndroidJUnit4.class)
+public class IkeSessionDigitalSignatureTest extends IkeSessionTestBase {
+    private static final int EXPECTED_AUTH_REQ_FRAG_COUNT = 3;
+
+    private static final String IKE_INIT_RESP =
+            "46B8ECA1E0D72A18BF3FA1C2CB1EE86F21202220000000000000015022000030"
+                    + "0000002C010100040300000C0100000C800E0100030000080300000503000008"
+                    + "0200000400000008040000022800008800020000328451C8A976CE69E407966A"
+                    + "50D7320C4197A15A07267CE1B16BAFF9BDBBDEC1FDCDAAF7175ADF9AA8DB55DB"
+                    + "2D70C012D01D914C4EDEF6E8B226868EA1D01B2ED0C4C5C86E6BFE566010EC0C"
+                    + "33BA1C93666430B88BDA0470D82CC4F4416F49E3E361E3017C9F27811A66718B"
+                    + "389E1800915D776D59AA528A7E1D1B7815D35144290000249FE8FABE7F43D917"
+                    + "CE370DE2FD9C22BBC082951AC26C1BA26DE795470F2C25BC2900001C00004004"
+                    + "AE388EC86D6D1A470D44142D01AB2E85A7AC14182900001C0000400544A235A4"
+                    + "171C884286B170F48FFC181DB428D87D290000080000402E290000100000402F"
+                    + "00020003000400050000000800004014";
+    private static final String IKE_AUTH_RESP_FRAG_1 =
+            "46B8ECA1E0D72A18BF3FA1C2CB1EE86F3520232000000001000004E0240004C4"
+                    + "00010002DF6750A2D1D5675006F9F6230BB886FFD20CFB973FD04963CFD7A528"
+                    + "560598C58CC44178B2FCBBBBB271387AC81A664B7E7F1055B912F8C686E287C9"
+                    + "D31684C66339151AB86DA3CF1DA664052FA97687634558A1E9E6B37E16A86BD1"
+                    + "68D76DA5E2E1E0B7E98EB662D80D542307015D2BF134EBBBE425D6954FE8C2C4"
+                    + "D31D16C16AA0521C3C481F873ECF25BB8B05AC6083775C1821CAAB1E35A3955D"
+                    + "85ACC599574142E1DD5B262D6E5365CBF6EBE92FFCC16BC29EC3239456F3B202"
+                    + "492551C0F6D752ADCCA56D506D50CC8809EF6BC56EAD005586F7168F76445FD3"
+                    + "1366CC62D32C0C19B28210B8F813F97CD6A447C3857EFD6EC483DDA8ACD9870E"
+                    + "5A21B9C66F0FA44496C0C3D05E8859A1A4CFC88155D0C411BABC13033DD41FA4"
+                    + "AF08CE7734A146687F374F95634D1F26843203CA1FFD05CA3EB150CEA02FBF14"
+                    + "712B7A1C9BC7616A086E7FCA059E7D64EFF98DB895B32F8F7002762AF7D12F23"
+                    + "31E9DD25174C4CE273E5392BBB48F50B7A3E0187181216265F6A4FC7B91BE0AB"
+                    + "C601A580149D4B07411AE99DDB1944B977E86ADC9746605C60A92B569EEFAFFC"
+                    + "3A888D187B75D8F13249689FC28EBCD62B5E03AF171F3A561F0DEA3B1A75F531"
+                    + "971157DCE1E7BC6E7789FF3E8156015BC9C521EFE48996B41471D33BF09864E4"
+                    + "2436E8D7EB6218CDE7716DA754A924B123A63E25585BF27F4AC043A0C4AECE38"
+                    + "BB59DD62F5C0EC657206A76CED1BD26262237DA1CA6815435992A825758DEBEC"
+                    + "DDF598A22B8242AC4E34E70704DBA7B7B73DC3E067C1C98764F8791F84C99156"
+                    + "947D1FFC875F36FCE24B89369C1B5BF1D4C999DCA28E72A528D0E0163C66C067"
+                    + "E71B5E0025C13DA93313942F9EDA230B3ADC254821A4CB1A5DC9D0C5F4DC4E8E"
+                    + "CE46B7B8C72D3C5923C9B30DF1EF7B4EDEDA8BD05C86CA0162AE1BF8F277878E"
+                    + "607401BAA8F06E3EA873FA4C137324C4E0699277CDF649FE7F0F01945EE25FA7"
+                    + "0E4A89737E58185B11B4CB52FD5B0497D3E3CD1CEE7B1FBB3E969DB6F4C324A1"
+                    + "32DC6A0EA21F41332435FD99140C286F8ABBBA926953ADBEED17D30AAD953909"
+                    + "1347EF6D87163D6B1FF32D8B11FFB2E69FAEE7FE913D3826FBA7F9D11E0E3C57"
+                    + "27625B37D213710B5DD8965DAEFD3F491E8C029E2BF361039949BADEC31D60AC"
+                    + "355F26EE41339C03CC9D9B01C3C7F288F0E9D6DFEE78231BDA9AC10FED135913"
+                    + "2836B1A17CE060742B7E5B738A7177CCD59F70337BA251409C377A0FA5333204"
+                    + "D8622BA8C06DE0BEF4F32B6D4D77BE9DE977445D8A2A08C5C38341CB7974FBFB"
+                    + "22C8F983A7D6CEF068DDB2281E6673453521C831C1826861005AE5F37649BC64"
+                    + "0A6360B23284861441A440F1C5AADE1AB53CA63DB17F4C314D493C4C44DE5F20"
+                    + "75E084D080F92791F30BDD88373D50AB5A07BC72B0E7FFFA593103964E55603E"
+                    + "F7FEB7CA0762A1A7B86B6CCAD88CD6CBC7C6935D21F5F06B2700588A2530E619"
+                    + "DA1648AC809F3DDF56ACE5951737568FFEC7E2AB1AA0AE01B03A7F5A29CE73C0"
+                    + "5D2801B17CAAD0121082E9952FAB16BA1C386336C62D4CF3A5019CF61609433E"
+                    + "1C083237D47C4CF575097F7BF9000EF6B6C497A44E6480154A35669AD276BF05"
+                    + "6CC730B4E5962B6AF96CC6D236AE85CEFDA6877173F72D2F614F6696D1F9DF07"
+                    + "E107758B0978F69BC9DBE0CCBF252C40A3FDF7CE9104D3344F7B73593CCD73E0";
+    private static final String IKE_AUTH_RESP_FRAG_2 =
+            "46B8ECA1E0D72A18BF3FA1C2CB1EE86F3520232000000001000000F0000000D4"
+                    + "00020002155211EA41B37BC5F20568A6AE57038EEE208F94F9B444004F1EF391"
+                    + "2CABFCF857B9CD95FAAA9489ED10A3F5C93510820E22E23FC55ED8049E067D72"
+                    + "3645C00E1E08611916CE72D7F0A84123B63A8F3B9E78DBBE39967B7BB074AF4D"
+                    + "BF2178D991EDBDD01908A14A266D09236DB963B14AC33D894F0F83A580209EFD"
+                    + "61875BB56273AA336C22D6A4D890B93E0D42435667830CC32E4F608500E18569"
+                    + "3E6C1D88C0B5AE427333C86468E3474DAA4D1506AAB2A4021309A33DD759D0D0"
+                    + "A8C98BF7FBEA8109361A9F194D0FD756";
+    private static final String DELETE_IKE_RESP =
+            "46B8ECA1E0D72A18BF3FA1C2CB1EE86F2E202520000000020000004C00000030"
+                    + "342842D8DA37C8EFB92ED37C4FBB23CBDC90445137D6A0AF489F9F03641DBA9D"
+                    + "02F6F59FD8A7A78C7261CEB8";
+
+    // Using IPv4 for transport mode Child SA. IPv6 is currently infeasible because the IKE server
+    // that generates the test vectors is running in an IPv4 only network.
+    private static final IkeTrafficSelector TRANSPORT_MODE_INBOUND_TS =
+            new IkeTrafficSelector(
+                    MIN_PORT,
+                    MAX_PORT,
+                    InetAddresses.parseNumericAddress("172.58.35.103"),
+                    InetAddresses.parseNumericAddress("172.58.35.103"));
+
+    // TODO(b/157510502): Add test for IKE Session setup in IPv6 network
+
+    private static final String LOCAL_ID_ASN1_DN =
+            "CN=client.test.ike.android.net, O=Android, C=US";
+    private static final String REMOTE_ID_ASN1_DN =
+            "CN=server.test.ike.android.net, O=Android, C=US";
+
+    private static X509Certificate sServerCaCert;
+    private static X509Certificate sClientEndCert;
+    private static X509Certificate sClientIntermediateCaCertOne;
+    private static X509Certificate sClientIntermediateCaCertTwo;
+    private static RSAPrivateKey sClientPrivateKey;
+
+    @BeforeClass
+    public static void setUpCertsBeforeClass() throws Exception {
+        sServerCaCert = CertUtils.createCertFromPemFile("server-a-self-signed-ca.pem");
+        sClientEndCert = CertUtils.createCertFromPemFile("client-a-end-cert.pem");
+        sClientIntermediateCaCertOne =
+                CertUtils.createCertFromPemFile("client-a-intermediate-ca-one.pem");
+        sClientIntermediateCaCertTwo =
+                CertUtils.createCertFromPemFile("client-a-intermediate-ca-two.pem");
+        sClientPrivateKey = CertUtils.createRsaPrivateKeyFromKeyFile("client-a-private-key.key");
+    }
+
+    private IkeSession openIkeSessionWithRemoteAddress(InetAddress remoteAddress) {
+        IkeSessionParams ikeParams =
+                new IkeSessionParams.Builder(sContext)
+                        .setNetwork(mTunNetwork)
+                        .setServerHostname(remoteAddress.getHostAddress())
+                        .addSaProposal(SaProposalTest.buildIkeSaProposalWithNormalModeCipher())
+                        .addSaProposal(SaProposalTest.buildIkeSaProposalWithCombinedModeCipher())
+                        .setLocalIdentification(
+                                new IkeDerAsn1DnIdentification(new X500Principal(LOCAL_ID_ASN1_DN)))
+                        .setRemoteIdentification(
+                                new IkeDerAsn1DnIdentification(
+                                        new X500Principal(REMOTE_ID_ASN1_DN)))
+                        .setAuthDigitalSignature(
+                                sServerCaCert,
+                                sClientEndCert,
+                                Arrays.asList(
+                                        sClientIntermediateCaCertOne, sClientIntermediateCaCertTwo),
+                                sClientPrivateKey)
+                        .build();
+
+        return new IkeSession(
+                sContext,
+                ikeParams,
+                buildTransportModeChildParamsWithTs(
+                        TRANSPORT_MODE_INBOUND_TS, TRANSPORT_MODE_OUTBOUND_TS),
+                mUserCbExecutor,
+                mIkeSessionCallback,
+                mFirstChildSessionCallback);
+    }
+
+    @Test
+    public void testIkeSessionSetupAndChildSessionSetupWithTransportMode() throws Exception {
+        // Open IKE Session
+        IkeSession ikeSession = openIkeSessionWithRemoteAddress(mRemoteAddress);
+        performSetupIkeAndFirstChildBlocking(
+                IKE_INIT_RESP,
+                EXPECTED_AUTH_REQ_FRAG_COUNT /* expectedReqPktCnt */,
+                IKE_AUTH_RESP_FRAG_1,
+                IKE_AUTH_RESP_FRAG_2);
+
+        // IKE INIT and IKE AUTH takes two exchanges. Message ID starts from 2
+        int expectedMsgId = 2;
+
+        verifyIkeSessionSetupBlocking();
+        verifyChildSessionSetupBlocking(
+                mFirstChildSessionCallback,
+                Arrays.asList(TRANSPORT_MODE_INBOUND_TS),
+                Arrays.asList(TRANSPORT_MODE_OUTBOUND_TS),
+                new ArrayList<LinkAddress>());
+        IpSecTransformCallRecord firstTransformRecordA =
+                mFirstChildSessionCallback.awaitNextCreatedIpSecTransform();
+        IpSecTransformCallRecord firstTransformRecordB =
+                mFirstChildSessionCallback.awaitNextCreatedIpSecTransform();
+        verifyCreateIpSecTransformPair(firstTransformRecordA, firstTransformRecordB);
+
+        // Close IKE Session
+        ikeSession.close();
+        performCloseIkeBlocking(expectedMsgId++, DELETE_IKE_RESP);
+        verifyCloseIkeAndChildBlocking(firstTransformRecordA, firstTransformRecordB);
+    }
+}
diff --git a/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeSessionPskTest.java b/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeSessionPskTest.java
index 661457f..ef865af 100644
--- a/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeSessionPskTest.java
+++ b/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeSessionPskTest.java
@@ -16,6 +16,7 @@
 
 package android.net.ipsec.ike.cts;
 
+import static android.app.AppOpsManager.OP_MANAGE_IPSEC_TUNNELS;
 import static android.net.ipsec.ike.exceptions.IkeProtocolException.ERROR_TYPE_NO_PROPOSAL_CHOSEN;
 
 import static org.junit.Assert.assertArrayEquals;
@@ -33,6 +34,8 @@
 
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
@@ -102,6 +105,21 @@
                 mFirstChildSessionCallback);
     }
 
+    @BeforeClass
+    public static void setUpTunnelPermissionBeforeClass() throws Exception {
+        // Under normal circumstances, the MANAGE_IPSEC_TUNNELS appop would be auto-granted, and
+        // a standard permission is insufficient. So we shell out the appop, to give us the
+        // right appop permissions.
+        setAppOp(OP_MANAGE_IPSEC_TUNNELS, true);
+    }
+
+    // This method is guaranteed to run in subclasses and will run after subclasses' @AfterClass
+    // methods.
+    @AfterClass
+    public static void tearDownTunnelPermissionAfterClass() throws Exception {
+        setAppOp(OP_MANAGE_IPSEC_TUNNELS, false);
+    }
+
     @Test
     public void testIkeSessionSetupAndChildSessionSetupWithTunnelMode() throws Exception {
         if (!hasTunnelsFeature()) return;
@@ -203,6 +221,4 @@
     }
 
     // TODO(b/155821007): Verify rekey process and handling IKE_AUTH failure
-
-    // TODO(b/155821007): Test creating transport mode Child SA
 }
diff --git a/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeSessionTestBase.java b/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeSessionTestBase.java
index ade9813..5b545c4 100644
--- a/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeSessionTestBase.java
+++ b/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeSessionTestBase.java
@@ -15,7 +15,6 @@
 
 package android.net.ipsec.ike.cts;
 
-import static android.app.AppOpsManager.OP_MANAGE_IPSEC_TUNNELS;
 import static android.net.ipsec.ike.IkeSessionConfiguration.EXTENSION_TYPE_FRAGMENTATION;
 import static android.system.OsConstants.AF_INET;
 import static android.system.OsConstants.AF_INET6;
@@ -43,6 +42,7 @@
 import android.net.ipsec.ike.IkeSessionConfiguration;
 import android.net.ipsec.ike.IkeSessionConnectionInfo;
 import android.net.ipsec.ike.IkeTrafficSelector;
+import android.net.ipsec.ike.TransportModeChildSessionParams;
 import android.net.ipsec.ike.TunnelModeChildSessionParams;
 import android.net.ipsec.ike.cts.TestNetworkUtils.TestNetworkCallback;
 import android.net.ipsec.ike.exceptions.IkeException;
@@ -103,6 +103,14 @@
                     MIN_PORT, MAX_PORT, EXPECTED_INTERNAL_ADDR, EXPECTED_INTERNAL_ADDR);
     static final IkeTrafficSelector TUNNEL_MODE_OUTBOUND_TS = DEFAULT_V4_TS;
 
+    // This value is align with the test vectors hex that are generated in an IPv4 environment
+    static final IkeTrafficSelector TRANSPORT_MODE_OUTBOUND_TS =
+            new IkeTrafficSelector(
+                    MIN_PORT,
+                    MAX_PORT,
+                    InetAddresses.parseNumericAddress("10.138.0.2"),
+                    InetAddresses.parseNumericAddress("10.138.0.2"));
+
     static final long IKE_DETERMINISTIC_INITIATOR_SPI = Long.parseLong("46B8ECA1E0D72A18", 16);
 
     // Static state to reduce setup/teardown
@@ -142,19 +150,12 @@
                 .getUiAutomation()
                 .adoptShellPermissionIdentity();
         sTNM = sContext.getSystemService(TestNetworkManager.class);
-
-        // Under normal circumstances, the MANAGE_IPSEC_TUNNELS appop would be auto-granted, and
-        // a standard permission is insufficient. So we shell out the appop, to give us the
-        // right appop permissions.
-        setAppOp(OP_MANAGE_IPSEC_TUNNELS, true);
     }
 
     // This method is guaranteed to run in subclasses and will run after subclasses' @AfterClass
     // methods.
     @AfterClass
     public static void tearDownPermissionAfterClass() throws Exception {
-        setAppOp(OP_MANAGE_IPSEC_TUNNELS, false);
-
         InstrumentationRegistry.getInstrumentation()
                 .getUiAutomation()
                 .dropShellPermissionIdentity();
@@ -197,7 +198,7 @@
         mTunFd.close();
     }
 
-    private static void setAppOp(int appop, boolean allow) {
+    static void setAppOp(int appop, boolean allow) {
         String opName = AppOpsManager.opToName(appop);
         for (String pkg : new String[] {"com.android.shell", sContext.getPackageName()}) {
             String cmd =
@@ -249,6 +250,16 @@
         }
     }
 
+    TransportModeChildSessionParams buildTransportModeChildParamsWithTs(
+            IkeTrafficSelector inboundTs, IkeTrafficSelector outboundTs) {
+        return new TransportModeChildSessionParams.Builder()
+                .addSaProposal(SaProposalTest.buildChildSaProposalWithCombinedModeCipher())
+                .addSaProposal(SaProposalTest.buildChildSaProposalWithNormalModeCipher())
+                .addInboundTrafficSelectors(inboundTs)
+                .addOutboundTrafficSelectors(outboundTs)
+                .build();
+    }
+
     TunnelModeChildSessionParams buildTunnelModeChildSessionParams() {
         return new TunnelModeChildSessionParams.Builder()
                 .addSaProposal(SaProposalTest.buildChildSaProposalWithNormalModeCipher())
@@ -258,7 +269,14 @@
                 .build();
     }
 
-    void performSetupIkeAndFirstChildBlocking(String ikeInitRespHex, String ikeAuthRespHex)
+    void performSetupIkeAndFirstChildBlocking(String ikeInitRespHex, String... ikeAuthRespHexes)
+            throws Exception {
+        performSetupIkeAndFirstChildBlocking(
+                ikeInitRespHex, 1 /* expectedAuthReqPktCnt */, ikeAuthRespHexes);
+    }
+
+    void performSetupIkeAndFirstChildBlocking(
+            String ikeInitRespHex, int expectedAuthReqPktCnt, String... ikeAuthRespHexes)
             throws Exception {
         mTunUtils.awaitReqAndInjectResp(
                 IKE_DETERMINISTIC_INITIATOR_SPI,
@@ -270,14 +288,8 @@
                 IKE_DETERMINISTIC_INITIATOR_SPI,
                 1 /* expectedMsgId */,
                 true /* expectedUseEncap */,
-                ikeAuthRespHex);
-    }
-
-    void performSetupIkeAndFirstChildBlocking(
-            String ikeInitRespHex, int expectedAuthReqPktCnt, String... ikeAuthRespPktHex)
-            throws Exception {
-        // TODO: Implemented in followup CL (aosp/1308675) to support awaiting multiple IKE AUTH
-        // request fragments and injecting multiple IKE AUTH response fragments
+                expectedAuthReqPktCnt,
+                ikeAuthRespHexes);
     }
 
     void performCloseIkeBlocking(int expectedMsgId, String deleteIkeRespHex) throws Exception {
@@ -522,7 +534,7 @@
         return sContext.getPackageManager().hasSystemFeature(PackageManager.FEATURE_IPSEC_TUNNELS);
     }
 
-    // TODO(b/148689509): Verify IKE Session setup using EAP and digital-signature-based auth
+    // TODO(b/148689509): Verify IKE Session setup using EAP
 
     // TODO(b/148689509): Verify hostname based creation
 }
diff --git a/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeTunUtils.java b/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeTunUtils.java
index 2bff63a..a9daf6a 100644
--- a/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeTunUtils.java
+++ b/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/IkeTunUtils.java
@@ -36,7 +36,9 @@
 import java.net.Inet6Address;
 import java.net.InetAddress;
 import java.nio.ByteBuffer;
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 import java.util.function.Predicate;
 
 public class IkeTunUtils extends TunUtils {
@@ -45,10 +47,13 @@
     private static final int NON_ESP_MARKER_LEN = 4;
     private static final byte[] NON_ESP_MARKER = new byte[NON_ESP_MARKER_LEN];
 
-    private static final int IKE_HEADER_LEN = 28;
     private static final int IKE_INIT_SPI_OFFSET = 0;
+    private static final int IKE_FIRST_PAYLOAD_OFFSET = 16;
     private static final int IKE_IS_RESP_BYTE_OFFSET = 19;
     private static final int IKE_MSG_ID_OFFSET = 20;
+    private static final int IKE_HEADER_LEN = 28;
+    private static final int IKE_FRAG_NUM_OFFSET = 32;
+    private static final int IKE_PAYLOAD_TYPE_SKF = 53;
 
     public IkeTunUtils(ParcelFileDescriptor tunFd) {
         super(tunFd);
@@ -65,16 +70,65 @@
             boolean expectedUseEncap,
             String ikeRespDataHex)
             throws Exception {
-        byte[] request =
-                awaitIkePacket(
-                        (pkt) -> {
-                            return isExpectedIkePkt(
-                                    pkt,
-                                    expectedInitIkeSpi,
-                                    expectedMsgId,
-                                    false /* expectedResp */,
-                                    expectedUseEncap);
-                        });
+        return awaitReqAndInjectResp(
+                        expectedInitIkeSpi,
+                        expectedMsgId,
+                        expectedUseEncap,
+                        1 /* expectedReqPktCnt */,
+                        ikeRespDataHex)
+                .get(0);
+    }
+
+    /**
+     * Await the expected IKE request (or the list of IKE request fragments) and inject an IKE
+     * response (or a list of response fragments)
+     *
+     * @param ikeRespDataHexes IKE response hex (or a list of response fragments) without IP/UDP
+     *     headers or NON ESP MARKER.
+     */
+    public List<byte[]> awaitReqAndInjectResp(
+            long expectedInitIkeSpi,
+            int expectedMsgId,
+            boolean expectedUseEncap,
+            int expectedReqPktCnt,
+            String... ikeRespDataHexes)
+            throws Exception {
+        List<byte[]> reqList = new ArrayList<>(expectedReqPktCnt);
+        if (expectedReqPktCnt == 1) {
+            // Expecting one complete IKE packet
+            byte[] req =
+                    awaitIkePacket(
+                            (pkt) -> {
+                                return isExpectedIkePkt(
+                                        pkt,
+                                        expectedInitIkeSpi,
+                                        expectedMsgId,
+                                        false /* expectedResp */,
+                                        expectedUseEncap);
+                            });
+            reqList.add(req);
+        } else {
+            // Expecting "expectedReqPktCnt" number of request fragments
+            for (int i = 0; i < expectedReqPktCnt; i++) {
+                // IKE Fragment number always starts from 1
+                int expectedFragNum = i + 1;
+                byte[] req =
+                        awaitIkePacket(
+                                (pkt) -> {
+                                    return isExpectedIkeFragPkt(
+                                            pkt,
+                                            expectedInitIkeSpi,
+                                            expectedMsgId,
+                                            false /* expectedResp */,
+                                            expectedUseEncap,
+                                            expectedFragNum);
+                                });
+                reqList.add(req);
+            }
+        }
+
+        // All request fragments have the same addresses and ports
+        byte[] request = reqList.get(0);
 
         // Build response header by flipping address and port
         InetAddress srcAddr = getAddress(request, false /* shouldGetSource */);
@@ -82,20 +136,20 @@
         int srcPort = getPort(request, false /* shouldGetSource */);
         int dstPort = getPort(request, true /* shouldGetSource */);
 
-        byte[] response =
-                buildIkePacket(
-                        srcAddr,
-                        dstAddr,
-                        srcPort,
-                        dstPort,
-                        expectedUseEncap,
-                        hexStringToByteArray(ikeRespDataHex));
-        injectPacket(response);
-        return request;
-    }
+        for (String hex : ikeRespDataHexes) {
+            byte[] response =
+                    buildIkePacket(
+                            srcAddr,
+                            dstAddr,
+                            srcPort,
+                            dstPort,
+                            expectedUseEncap,
+                            hexStringToByteArray(hex));
+            injectPacket(response);
+        }
 
-    // TODO: Implemented in followup CL (aosp/1308675) to support awaiting multiple
-    // request fragments and injecting multiple  response fragments
+        return reqList;
+    }
 
     private byte[] awaitIkePacket(Predicate<byte[]> pktVerifier) throws Exception {
         long endTime = System.currentTimeMillis() + TIMEOUT;
@@ -129,31 +183,38 @@
             int expectedMsgId,
             boolean expectedResp,
             boolean expectedUseEncap) {
-        int ipProtocolOffset = 0;
-        int ikeOffset = 0;
-        if (isIpv6(pkt)) {
-            // IPv6 UDP expectedUseEncap not supported by kernels; assume non-expectedUseEncap.
-            ipProtocolOffset = IP6_PROTO_OFFSET;
-            ikeOffset = IP6_HDRLEN + UDP_HDRLEN;
-        } else {
-            // Use default IPv4 header length (assuming no options)
-            ipProtocolOffset = IP4_PROTO_OFFSET;
-            ikeOffset = IP4_HDRLEN + UDP_HDRLEN;
-
-            if (expectedUseEncap) {
-                if (hasNonEspMarker(pkt)) {
-                    ikeOffset += NON_ESP_MARKER_LEN;
-                } else {
-                    return false;
-                }
-            }
-        }
+        int ipProtocolOffset = isIpv6(pkt) ? IP6_PROTO_OFFSET : IP4_PROTO_OFFSET;
+        int ikeOffset = getIkeOffset(pkt, expectedUseEncap);
 
         return pkt[ipProtocolOffset] == IPPROTO_UDP
+                && expectedUseEncap == hasNonEspMarker(pkt)
                 && isExpectedSpiAndMsgId(
                         pkt, ikeOffset, expectedInitIkeSpi, expectedMsgId, expectedResp);
     }
 
+    private static boolean isExpectedIkeFragPkt(
+            byte[] pkt,
+            long expectedInitIkeSpi,
+            int expectedMsgId,
+            boolean expectedResp,
+            boolean expectedUseEncap,
+            int expectedFragNum) {
+        return isExpectedIkePkt(
+                        pkt, expectedInitIkeSpi, expectedMsgId, expectedResp, expectedUseEncap)
+                && isExpectedFragNum(pkt, getIkeOffset(pkt, expectedUseEncap), expectedFragNum);
+    }
+
+    private static int getIkeOffset(byte[] pkt, boolean useEncap) {
+        if (isIpv6(pkt)) {
+            // IPv6 UDP expectedUseEncap not supported by kernels; assume non-expectedUseEncap.
+            return IP6_HDRLEN + UDP_HDRLEN;
+        } else {
+            // Use default IPv4 header length (assuming no options)
+            int ikeOffset = IP4_HDRLEN + UDP_HDRLEN;
+            return useEncap ? ikeOffset + NON_ESP_MARKER_LEN : ikeOffset;
+        }
+    }
+
     private static boolean hasNonEspMarker(byte[] pkt) {
         ByteBuffer buffer = ByteBuffer.wrap(pkt);
         int ikeOffset = IP4_HDRLEN + UDP_HDRLEN;
@@ -186,6 +247,25 @@
         // TODO: Check SPI and packet direction
     }
 
+    private static boolean isExpectedFragNum(byte[] pkt, int ikeOffset, int expectedFragNum) {
+        ByteBuffer buffer = ByteBuffer.wrap(pkt);
+        buffer.get(new byte[ikeOffset]);
+        buffer.mark(); // Mark this position so that later we can reset back here
+
+        // Check if it is a fragment packet
+        buffer.get(new byte[IKE_FIRST_PAYLOAD_OFFSET]);
+        int firstPayload = Byte.toUnsignedInt(buffer.get());
+        if (firstPayload != IKE_PAYLOAD_TYPE_SKF) {
+            return false;
+        }
+
+        // Check fragment number
+        buffer.reset();
+        buffer.get(new byte[IKE_FRAG_NUM_OFFSET]);
+        int fragNum = Short.toUnsignedInt(buffer.getShort());
+        return expectedFragNum == fragNum;
+    }
+
     private static InetAddress getAddress(byte[] pkt, boolean shouldGetSource) throws Exception {
         int ipLen = isIpv6(pkt) ? IP6_ADDR_LEN : IP4_ADDR_LEN;
         int srcIpOffset = isIpv6(pkt) ? IP6_ADDR_OFFSET : IP4_ADDR_OFFSET;
diff --git a/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/TunUtils.java b/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/TunUtils.java
index cb1d826..5539dbc 100644
--- a/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/TunUtils.java
+++ b/tests/cts/net/ipsec/src/android/net/ipsec/ike/cts/TunUtils.java
@@ -47,7 +47,7 @@
     private static final String TAG = TunUtils.class.getSimpleName();
 
     private static final int DATA_BUFFER_LEN = 4096;
-    static final int TIMEOUT = 100;
+    static final int TIMEOUT = 500;
 
     static final int IP4_PROTO_OFFSET = 9;
     static final int IP6_PROTO_OFFSET = 6;