diff --git a/docs/Settings.md b/docs/Settings.md
index 9df659b894..8d6d947245 100644
--- a/docs/Settings.md
+++ b/docs/Settings.md
@@ -177,6 +177,7 @@ These parameters are accessed by calling [GetParam](./api/GetParam.md) or [SetPa
 | `QUIC_PARAM_CONN_STATISTICS_V2`<br> 22            | QUIC_STATISTICS_V2            | Get-only  | Connection-level statistics, version 2.                                                   |
 | `QUIC_PARAM_CONN_STATISTICS_V2_PLAT`<br> 23       | QUIC_STATISTICS_V2            | Get-only  | Connection-level statistics with platform-specific time format, version 2.                |
 | `QUIC_PARAM_CONN_ORIG_DEST_CID` <br> 24           | uint8_t[]                     | Get-only  | The original destination connection ID used by the client to connect to the server.       |
+| `QUIC_PARAM_CONN_DSCP` <br> 25                    | uint8_t                       | Both      | The DiffServ Code Point put in the DiffServ field (formerly TypeOfService/TrafficClass) on packets sent from this connection. |
 
 ### QUIC_PARAM_CONN_STATISTICS_V2
 
diff --git a/src/core/binding.c b/src/core/binding.c
index 348e1228d0..22f03f5f62 100644
--- a/src/core/binding.c
+++ b/src/core/binding.c
@@ -803,7 +803,7 @@ QuicBindingProcessStatelessOperation(
         Binding,
         OperationType);
 
-    CXPLAT_SEND_CONFIG SendConfig = { RecvPacket->Route, 0, CXPLAT_ECN_NON_ECT, 0 };
+    CXPLAT_SEND_CONFIG SendConfig = { RecvPacket->Route, 0, CXPLAT_ECN_NON_ECT, 0, 0 };
     CXPLAT_SEND_DATA* SendData = CxPlatSendDataAlloc(Binding->Socket, &SendConfig);
     if (SendData == NULL) {
         QuicTraceEvent(
diff --git a/src/core/connection.c b/src/core/connection.c
index b59d19ba45..e58ad9974c 100644
--- a/src/core/connection.c
+++ b/src/core/connection.c
@@ -6623,6 +6623,27 @@ QuicConnParamSet(
         return QUIC_STATUS_SUCCESS;
     }
 
+    case QUIC_PARAM_CONN_DSCP:
+    {
+        if (BufferLength != sizeof(uint8_t) || Buffer == NULL) {
+            Status = QUIC_STATUS_INVALID_PARAMETER;
+            break;
+        }
+
+        uint8_t DSCP = 0;
+        CxPlatCopyMemory(&DSCP, Buffer, BufferLength);
+
+        if (DSCP > CXPLAT_MAX_DSCP) {
+            Status = QUIC_STATUS_INVALID_PARAMETER;
+            break;
+        }
+
+        Connection->DSCP = DSCP;
+
+        Status = QUIC_STATUS_SUCCESS;
+        break;
+    }
+
     //
     // Private
     //
@@ -7207,27 +7228,55 @@ QuicConnParamGet(
     }
 
     case QUIC_PARAM_CONN_ORIG_DEST_CID:
+
         if (Connection->OrigDestCID == NULL) {
             Status = QUIC_STATUS_INVALID_STATE;
             break;
         }
+
         if (*BufferLength < Connection->OrigDestCID->Length) {
             Status = QUIC_STATUS_BUFFER_TOO_SMALL;
             *BufferLength = Connection->OrigDestCID->Length;
             break;
         }
+
         if (Buffer == NULL) {
             Status = QUIC_STATUS_INVALID_PARAMETER;
             break;
         }
+
         CxPlatCopyMemory(
             Buffer,
             Connection->OrigDestCID->Data,
             Connection->OrigDestCID->Length);
+
         //
         // Tell app how much buffer we copied.
         //
         *BufferLength = Connection->OrigDestCID->Length;
+
+        Status = QUIC_STATUS_SUCCESS;
+        break;
+
+     case QUIC_PARAM_CONN_DSCP:
+
+        if (*BufferLength < sizeof(Connection->DSCP)) {
+            Status = QUIC_STATUS_BUFFER_TOO_SMALL;
+            *BufferLength = sizeof(Connection->DSCP);
+            break;
+        }
+
+        if (Buffer == NULL) {
+            Status = QUIC_STATUS_INVALID_PARAMETER;
+            break;
+        }
+
+        CxPlatCopyMemory(
+            Buffer,
+            &Connection->DSCP,
+            sizeof(Connection->DSCP));
+
+        *BufferLength = sizeof(Connection->DSCP);
         Status = QUIC_STATUS_SUCCESS;
         break;
 
diff --git a/src/core/connection.h b/src/core/connection.h
index c754115f52..0b3dcc5017 100644
--- a/src/core/connection.h
+++ b/src/core/connection.h
@@ -462,6 +462,12 @@ typedef struct QUIC_CONNECTION {
     //
     uint8_t PeerReorderingThreshold;
 
+    //
+    // DSCP value to set on all sends from this connection.
+    // Default value of 0.
+    //
+    uint8_t DSCP;
+
     //
     // The ACK frequency sequence number we are currently using to send.
     //
diff --git a/src/core/packet_builder.c b/src/core/packet_builder.c
index 9d380fa09a..05eb49286c 100644
--- a/src/core/packet_builder.c
+++ b/src/core/packet_builder.c
@@ -265,7 +265,8 @@ QuicPacketBuilderPrepare(
                         DatagramSize),
                 Builder->EcnEctSet ? CXPLAT_ECN_ECT_0 : CXPLAT_ECN_NON_ECT,
                 Builder->Connection->Registration->ExecProfile == QUIC_EXECUTION_PROFILE_TYPE_MAX_THROUGHPUT ?
-                    CXPLAT_SEND_FLAGS_MAX_THROUGHPUT : CXPLAT_SEND_FLAGS_NONE
+                    CXPLAT_SEND_FLAGS_MAX_THROUGHPUT : CXPLAT_SEND_FLAGS_NONE,
+                Connection->DSCP
             };
             Builder->SendData =
                 CxPlatSendDataAlloc(Builder->Path->Binding->Socket, &SendConfig);
diff --git a/src/cs/lib/msquic_generated.cs b/src/cs/lib/msquic_generated.cs
index 3e6f9d96b7..e725408c40 100644
--- a/src/cs/lib/msquic_generated.cs
+++ b/src/cs/lib/msquic_generated.cs
@@ -3447,6 +3447,9 @@ internal static unsafe partial class MsQuic
         [NativeTypeName("#define QUIC_PARAM_CONN_ORIG_DEST_CID 0x05000018")]
         internal const uint QUIC_PARAM_CONN_ORIG_DEST_CID = 0x05000018;
 
+        [NativeTypeName("#define QUIC_PARAM_CONN_DSCP 0x50000019")]
+        internal const uint QUIC_PARAM_CONN_DSCP = 0x50000019;
+
         [NativeTypeName("#define QUIC_PARAM_TLS_HANDSHAKE_INFO 0x06000000")]
         internal const uint QUIC_PARAM_TLS_HANDSHAKE_INFO = 0x06000000;
 
diff --git a/src/generated/linux/datapath_winkernel.c.clog.h b/src/generated/linux/datapath_winkernel.c.clog.h
index 4e2479cf34..fa75a3704b 100644
--- a/src/generated/linux/datapath_winkernel.c.clog.h
+++ b/src/generated/linux/datapath_winkernel.c.clog.h
@@ -213,6 +213,42 @@ tracepoint(CLOG_DATAPATH_WINKERNEL_C, DatapathQueryRecvMaxCoalescedSizeFailedAsy
 
 
 
+/*----------------------------------------------------------
+// Decoder Ring for DatapathTestSetIpv6TrafficClassFailed
+// [data] Test setting IPV6_TCLASS failed, 0x%x
+// QuicTraceLogWarning(
+                DatapathTestSetIpv6TrafficClassFailed,
+                "[data] Test setting IPV6_TCLASS failed, 0x%x",
+                Status);
+// arg2 = arg2 = Status = arg2
+----------------------------------------------------------*/
+#ifndef _clog_3_ARGS_TRACE_DatapathTestSetIpv6TrafficClassFailed
+#define _clog_3_ARGS_TRACE_DatapathTestSetIpv6TrafficClassFailed(uniqueId, encoded_arg_string, arg2)\
+tracepoint(CLOG_DATAPATH_WINKERNEL_C, DatapathTestSetIpv6TrafficClassFailed , arg2);\
+
+#endif
+
+
+
+
+/*----------------------------------------------------------
+// Decoder Ring for DatapathTestSetIpv6TrafficClassFailedAsync
+// [data] Test setting IPV6_TCLASS failed (async), 0x%x
+// QuicTraceLogWarning(
+                DatapathTestSetIpv6TrafficClassFailedAsync,
+                "[data] Test setting IPV6_TCLASS failed (async), 0x%x",
+                Status);
+// arg2 = arg2 = Status = arg2
+----------------------------------------------------------*/
+#ifndef _clog_3_ARGS_TRACE_DatapathTestSetIpv6TrafficClassFailedAsync
+#define _clog_3_ARGS_TRACE_DatapathTestSetIpv6TrafficClassFailedAsync(uniqueId, encoded_arg_string, arg2)\
+tracepoint(CLOG_DATAPATH_WINKERNEL_C, DatapathTestSetIpv6TrafficClassFailedAsync , arg2);\
+
+#endif
+
+
+
+
 /*----------------------------------------------------------
 // Decoder Ring for DatapathDropEmptyMdl
 // [%p] Dropping datagram with empty mdl.
diff --git a/src/generated/linux/datapath_winkernel.c.clog.h.lttng.h b/src/generated/linux/datapath_winkernel.c.clog.h.lttng.h
index 6efeb61ee7..704051c779 100644
--- a/src/generated/linux/datapath_winkernel.c.clog.h.lttng.h
+++ b/src/generated/linux/datapath_winkernel.c.clog.h.lttng.h
@@ -191,6 +191,44 @@ TRACEPOINT_EVENT(CLOG_DATAPATH_WINKERNEL_C, DatapathQueryRecvMaxCoalescedSizeFai
 
 
 
+/*----------------------------------------------------------
+// Decoder Ring for DatapathTestSetIpv6TrafficClassFailed
+// [data] Test setting IPV6_TCLASS failed, 0x%x
+// QuicTraceLogWarning(
+                DatapathTestSetIpv6TrafficClassFailed,
+                "[data] Test setting IPV6_TCLASS failed, 0x%x",
+                Status);
+// arg2 = arg2 = Status = arg2
+----------------------------------------------------------*/
+TRACEPOINT_EVENT(CLOG_DATAPATH_WINKERNEL_C, DatapathTestSetIpv6TrafficClassFailed,
+    TP_ARGS(
+        unsigned int, arg2), 
+    TP_FIELDS(
+        ctf_integer(unsigned int, arg2, arg2)
+    )
+)
+
+
+
+/*----------------------------------------------------------
+// Decoder Ring for DatapathTestSetIpv6TrafficClassFailedAsync
+// [data] Test setting IPV6_TCLASS failed (async), 0x%x
+// QuicTraceLogWarning(
+                DatapathTestSetIpv6TrafficClassFailedAsync,
+                "[data] Test setting IPV6_TCLASS failed (async), 0x%x",
+                Status);
+// arg2 = arg2 = Status = arg2
+----------------------------------------------------------*/
+TRACEPOINT_EVENT(CLOG_DATAPATH_WINKERNEL_C, DatapathTestSetIpv6TrafficClassFailedAsync,
+    TP_ARGS(
+        unsigned int, arg2), 
+    TP_FIELDS(
+        ctf_integer(unsigned int, arg2, arg2)
+    )
+)
+
+
+
 /*----------------------------------------------------------
 // Decoder Ring for DatapathDropEmptyMdl
 // [%p] Dropping datagram with empty mdl.
diff --git a/src/generated/linux/datapath_winuser.c.clog.h b/src/generated/linux/datapath_winuser.c.clog.h
index c285e4e96b..b26f8b70b0 100644
--- a/src/generated/linux/datapath_winuser.c.clog.h
+++ b/src/generated/linux/datapath_winuser.c.clog.h
@@ -123,6 +123,42 @@ tracepoint(CLOG_DATAPATH_WINUSER_C, DatapathQueryRecvMaxCoalescedSizeFailed , ar
 
 
 
+/*----------------------------------------------------------
+// Decoder Ring for DatapathOpenUdpv6SocketFailed
+// [data] UDPv6 helper socket failed to open, 0x%x
+// QuicTraceLogWarning(
+            DatapathOpenUdpv6SocketFailed,
+            "[data] UDPv6 helper socket failed to open, 0x%x",
+            WsaError);
+// arg2 = arg2 = WsaError = arg2
+----------------------------------------------------------*/
+#ifndef _clog_3_ARGS_TRACE_DatapathOpenUdpv6SocketFailed
+#define _clog_3_ARGS_TRACE_DatapathOpenUdpv6SocketFailed(uniqueId, encoded_arg_string, arg2)\
+tracepoint(CLOG_DATAPATH_WINUSER_C, DatapathOpenUdpv6SocketFailed , arg2);\
+
+#endif
+
+
+
+
+/*----------------------------------------------------------
+// Decoder Ring for DatapathTestSetIpv6TrafficClassFailed
+// [data] Test setting IPV6_TCLASS failed, 0x%x
+// QuicTraceLogWarning(
+            DatapathTestSetIpv6TrafficClassFailed,
+            "[data] Test setting IPV6_TCLASS failed, 0x%x",
+            WsaError);
+// arg2 = arg2 = WsaError = arg2
+----------------------------------------------------------*/
+#ifndef _clog_3_ARGS_TRACE_DatapathTestSetIpv6TrafficClassFailed
+#define _clog_3_ARGS_TRACE_DatapathTestSetIpv6TrafficClassFailed(uniqueId, encoded_arg_string, arg2)\
+tracepoint(CLOG_DATAPATH_WINUSER_C, DatapathTestSetIpv6TrafficClassFailed , arg2);\
+
+#endif
+
+
+
+
 /*----------------------------------------------------------
 // Decoder Ring for DatapathRecvEmpty
 // [data][%p] Dropping datagram with empty payload.
diff --git a/src/generated/linux/datapath_winuser.c.clog.h.lttng.h b/src/generated/linux/datapath_winuser.c.clog.h.lttng.h
index 6af0327b8e..bcd390782c 100644
--- a/src/generated/linux/datapath_winuser.c.clog.h.lttng.h
+++ b/src/generated/linux/datapath_winuser.c.clog.h.lttng.h
@@ -96,6 +96,44 @@ TRACEPOINT_EVENT(CLOG_DATAPATH_WINUSER_C, DatapathQueryRecvMaxCoalescedSizeFaile
 
 
 
+/*----------------------------------------------------------
+// Decoder Ring for DatapathOpenUdpv6SocketFailed
+// [data] UDPv6 helper socket failed to open, 0x%x
+// QuicTraceLogWarning(
+            DatapathOpenUdpv6SocketFailed,
+            "[data] UDPv6 helper socket failed to open, 0x%x",
+            WsaError);
+// arg2 = arg2 = WsaError = arg2
+----------------------------------------------------------*/
+TRACEPOINT_EVENT(CLOG_DATAPATH_WINUSER_C, DatapathOpenUdpv6SocketFailed,
+    TP_ARGS(
+        unsigned int, arg2), 
+    TP_FIELDS(
+        ctf_integer(unsigned int, arg2, arg2)
+    )
+)
+
+
+
+/*----------------------------------------------------------
+// Decoder Ring for DatapathTestSetIpv6TrafficClassFailed
+// [data] Test setting IPV6_TCLASS failed, 0x%x
+// QuicTraceLogWarning(
+            DatapathTestSetIpv6TrafficClassFailed,
+            "[data] Test setting IPV6_TCLASS failed, 0x%x",
+            WsaError);
+// arg2 = arg2 = WsaError = arg2
+----------------------------------------------------------*/
+TRACEPOINT_EVENT(CLOG_DATAPATH_WINUSER_C, DatapathTestSetIpv6TrafficClassFailed,
+    TP_ARGS(
+        unsigned int, arg2), 
+    TP_FIELDS(
+        ctf_integer(unsigned int, arg2, arg2)
+    )
+)
+
+
+
 /*----------------------------------------------------------
 // Decoder Ring for DatapathRecvEmpty
 // [data][%p] Dropping datagram with empty payload.
diff --git a/src/inc/msquic.h b/src/inc/msquic.h
index b8dc5471db..79e96b5199 100644
--- a/src/inc/msquic.h
+++ b/src/inc/msquic.h
@@ -923,6 +923,7 @@ typedef struct QUIC_SCHANNEL_CREDENTIAL_ATTRIBUTE_W {
 #define QUIC_PARAM_CONN_STATISTICS_V2                   0x05000016  // QUIC_STATISTICS_V2
 #define QUIC_PARAM_CONN_STATISTICS_V2_PLAT              0x05000017  // QUIC_STATISTICS_V2
 #define QUIC_PARAM_CONN_ORIG_DEST_CID                   0x05000018  // uint8_t[]
+#define QUIC_PARAM_CONN_DSCP                            0x50000019  // uint8_t
 
 //
 // Parameters for TLS.
diff --git a/src/inc/quic_datapath.h b/src/inc/quic_datapath.h
index 9975f762a1..ec52c85d97 100644
--- a/src/inc/quic_datapath.h
+++ b/src/inc/quic_datapath.h
@@ -58,6 +58,17 @@ typedef enum CXPLAT_ECN_TYPE {
 //
 #define CXPLAT_ECN_FROM_TOS(ToS) (CXPLAT_ECN_TYPE)((ToS) & 0x3)
 
+//
+// Helper to get the DSCP value from the Type of Service field of received data.
+//
+#define CXPLAT_DSCP_FROM_TOS(ToS) (uint8_t)((ToS) >> 2)
+
+//
+// Define the maximum type of service value allowed.
+// Note: this is without the ECN bits included
+//
+#define CXPLAT_MAX_DSCP 63
+
 //
 // The maximum IP MTU this implementation supports for QUIC.
 //
@@ -444,6 +455,7 @@ CxPlatDataPathUpdateConfig(
 #define CXPLAT_DATAPATH_FEATURE_TCP                   0x0020
 #define CXPLAT_DATAPATH_FEATURE_RAW                   0x0040
 #define CXPLAT_DATAPATH_FEATURE_TTL                   0x0080
+#define CXPLAT_DATAPATH_FEATURE_DSCP                  0x0100
 
 //
 // Queries the currently supported features of the datapath.
@@ -675,6 +687,7 @@ typedef struct CXPLAT_SEND_CONFIG {
     uint16_t MaxPacketSize;
     uint8_t ECN; // CXPLAT_ECN_TYPE
     uint8_t Flags; // CXPLAT_SEND_FLAGS
+    uint8_t DSCP;
 } CXPLAT_SEND_CONFIG;
 
 //
diff --git a/src/manifest/clog.sidecar b/src/manifest/clog.sidecar
index 907d055946..be36e869b4 100644
--- a/src/manifest/clog.sidecar
+++ b/src/manifest/clog.sidecar
@@ -2695,6 +2695,18 @@
       ],
       "macroName": "QuicTraceLogWarning"
     },
+    "DatapathOpenUdpv6SocketFailed": {
+      "ModuleProperites": {},
+      "TraceString": "[data] UDPv6 helper socket failed to open, 0x%x",
+      "UniqueId": "DatapathOpenUdpv6SocketFailed",
+      "splitArgs": [
+        {
+          "DefinationEncoding": "x",
+          "MacroVariableName": "arg2"
+        }
+      ],
+      "macroName": "QuicTraceLogWarning"
+    },
     "DatapathQueryRecvMaxCoalescedSizeFailed": {
       "ModuleProperites": {},
       "TraceString": "[data] Query for UDP_RECV_MAX_COALESCED_SIZE failed, 0x%x",
@@ -3027,6 +3039,30 @@
       ],
       "macroName": "QuicTraceLogVerbose"
     },
+    "DatapathTestSetIpv6TrafficClassFailed": {
+      "ModuleProperites": {},
+      "TraceString": "[data] Test setting IPV6_TCLASS failed, 0x%x",
+      "UniqueId": "DatapathTestSetIpv6TrafficClassFailed",
+      "splitArgs": [
+        {
+          "DefinationEncoding": "x",
+          "MacroVariableName": "arg2"
+        }
+      ],
+      "macroName": "QuicTraceLogWarning"
+    },
+    "DatapathTestSetIpv6TrafficClassFailedAsync": {
+      "ModuleProperites": {},
+      "TraceString": "[data] Test setting IPV6_TCLASS failed (async), 0x%x",
+      "UniqueId": "DatapathTestSetIpv6TrafficClassFailedAsync",
+      "splitArgs": [
+        {
+          "DefinationEncoding": "x",
+          "MacroVariableName": "arg2"
+        }
+      ],
+      "macroName": "QuicTraceLogWarning"
+    },
     "DatapathTooLarge": {
       "ModuleProperites": {},
       "TraceString": "[data][%p] Received larger than expected datagram from %!ADDR!",
@@ -14199,6 +14235,11 @@
         "TraceID": "DatapathOpenUdpSocketFailedAsync",
         "EncodingString": "[data] UDP send segmentation helper socket failed to open (async), 0x%x"
       },
+      {
+        "UniquenessHash": "9af95ba3-6d62-261f-fb94-75465f7084ff",
+        "TraceID": "DatapathOpenUdpv6SocketFailed",
+        "EncodingString": "[data] UDPv6 helper socket failed to open, 0x%x"
+      },
       {
         "UniquenessHash": "1ba702fe-3407-9bab-a2bf-4f694b478ac0",
         "TraceID": "DatapathQueryRecvMaxCoalescedSizeFailed",
@@ -14294,6 +14335,16 @@
         "TraceID": "DatapathTcpAuxBinding",
         "EncodingString": "[data][%p] Binding TCP socket to %s"
       },
+      {
+        "UniquenessHash": "576dad43-cdc4-7cbc-817e-f8831afa4980",
+        "TraceID": "DatapathTestSetIpv6TrafficClassFailed",
+        "EncodingString": "[data] Test setting IPV6_TCLASS failed, 0x%x"
+      },
+      {
+        "UniquenessHash": "bac8baf4-caa7-65ff-f815-8e27065cc9ed",
+        "TraceID": "DatapathTestSetIpv6TrafficClassFailedAsync",
+        "EncodingString": "[data] Test setting IPV6_TCLASS failed (async), 0x%x"
+      },
       {
         "UniquenessHash": "a07c9538-e6d7-3c41-1367-ce58f2df4d9e",
         "TraceID": "DatapathTooLarge",
diff --git a/src/perf/lib/Tcp.cpp b/src/perf/lib/Tcp.cpp
index 9d71308c5c..fd328b1651 100644
--- a/src/perf/lib/Tcp.cpp
+++ b/src/perf/lib/Tcp.cpp
@@ -1088,7 +1088,7 @@ QUIC_BUFFER* TcpConnection::NewSendBuffer()
         return nullptr;
     }
     if (!BatchedSendData) {
-        CXPLAT_SEND_CONFIG SendConfig = { &Route, TLS_BLOCK_SIZE, CXPLAT_ECN_NON_ECT, 0 };
+        CXPLAT_SEND_CONFIG SendConfig = { &Route, TLS_BLOCK_SIZE, CXPLAT_ECN_NON_ECT, 0, 0 };
         BatchedSendData = CxPlatSendDataAlloc(Socket, &SendConfig);
         if (!BatchedSendData) { return nullptr; }
     }
diff --git a/src/platform/datapath_epoll.c b/src/platform/datapath_epoll.c
index 925880b36a..4601181cf9 100644
--- a/src/platform/datapath_epoll.c
+++ b/src/platform/datapath_epoll.c
@@ -340,6 +340,7 @@ CxPlatDataPathCalculateFeatureSupport(
 
     Datapath->Features |= CXPLAT_DATAPATH_FEATURE_TCP;
     Datapath->Features |= CXPLAT_DATAPATH_FEATURE_TTL;
+    Datapath->Features |= CXPLAT_DATAPATH_FEATURE_DSCP;
 }
 
 void
@@ -887,7 +888,6 @@ CxPlatSocketContextInitialize(
             goto Exit;
         }
 
-
     #ifdef UDP_GRO
         if (SocketContext->DatapathPartition->Datapath->Features & CXPLAT_DATAPATH_FEATURE_RECV_COALESCING) {
             Option = TRUE;
@@ -2264,6 +2264,7 @@ SendDataAlloc(
         SendData->AlreadySentCount = 0;
         SendData->ControlBufferLength = 0;
         SendData->ECN = Config->ECN;
+        SendData->DSCP = Config->DSCP;
         SendData->Flags = Config->Flags;
         SendData->OnConnectedSocket = Socket->Connected;
         SendData->SegmentationSupported =
@@ -2478,7 +2479,7 @@ CxPlatSendDataPopulateAncillaryData(
     CMsg->cmsg_level = SendData->LocalAddress.Ip.sa_family == AF_INET ? IPPROTO_IP : IPPROTO_IPV6;
     CMsg->cmsg_type = SendData->LocalAddress.Ip.sa_family == AF_INET ? IP_TOS : IPV6_TCLASS;
     CMsg->cmsg_len = CMSG_LEN(sizeof(int));
-    *(int*)CMSG_DATA(CMsg) = SendData->ECN;
+    *(int*)CMSG_DATA(CMsg) = SendData->ECN | (SendData->DSCP << 2);
 
     if (!SendData->OnConnectedSocket) {
         if (SendData->LocalAddress.Ip.sa_family == AF_INET) {
diff --git a/src/platform/datapath_kqueue.c b/src/platform/datapath_kqueue.c
index 0bb64fa330..cd4e4554ca 100644
--- a/src/platform/datapath_kqueue.c
+++ b/src/platform/datapath_kqueue.c
@@ -1626,6 +1626,7 @@ CxPlatSendDataAlloc(
         CxPlatZeroMemory(SendData, sizeof(*SendData));
         SendData->Owner = SocketContext->DatapathPartition;
         SendData->ECN = Config->ECN;
+        SendData->DSCP = Config->DSCP;
         SendData->SegmentSize =
             (Socket->Datapath->Features & CXPLAT_DATAPATH_FEATURE_SEND_SEGMENTATION)
                 ? Config->MaxPacketSize : 0;
@@ -1981,7 +1982,7 @@ CxPlatSocketSendInternal(
     CMsg->cmsg_level = RemoteAddress->Ip.sa_family == QUIC_ADDRESS_FAMILY_INET ? IPPROTO_IP : IPPROTO_IPV6;
     CMsg->cmsg_type = RemoteAddress->Ip.sa_family == QUIC_ADDRESS_FAMILY_INET ? IP_TOS : IPV6_TCLASS;
     CMsg->cmsg_len = CMSG_LEN(sizeof(int));
-    *(int *)CMSG_DATA(CMsg) = SendData->ECN;
+    *(int *)CMSG_DATA(CMsg) = SendData->ECN | (SendData->DSCP << 2);
 
     if (!SocketContext->Binding->Connected) {
         Mhdr.msg_name = &MappedRemoteAddress;
diff --git a/src/platform/datapath_raw.c b/src/platform/datapath_raw.c
index 57f342d91e..e860e40c1d 100644
--- a/src/platform/datapath_raw.c
+++ b/src/platform/datapath_raw.c
@@ -371,7 +371,7 @@ RawSocketSend(
     const CXPLAT_INTERFACE* Interface = CxPlatDpRawGetInterfaceFromQueue(Route->Queue);
 
     CxPlatFramingWriteHeaders(
-        Socket, Route, &SendData->Buffer, SendData->ECN,
+        Socket, Route, &SendData->Buffer, SendData->ECN, SendData->DSCP,
         Interface->OffloadStatus.Transmit.NetworkLayerXsum,
         Interface->OffloadStatus.Transmit.TransportLayerXsum,
         Route->TcpState.SequenceNumber,
diff --git a/src/platform/datapath_raw.h b/src/platform/datapath_raw.h
index f54adc03a0..c980eee3e9 100644
--- a/src/platform/datapath_raw.h
+++ b/src/platform/datapath_raw.h
@@ -377,6 +377,7 @@ CxPlatFramingWriteHeaders(
     _In_ const CXPLAT_ROUTE* Route,
     _Inout_ QUIC_BUFFER* Buffer,
     _In_ CXPLAT_ECN_TYPE ECN,
+    _In_ uint8_t DSCP,
     _In_ BOOLEAN SkipNetworkLayerXsum,
     _In_ BOOLEAN SkipTransportLayerXsum,
     _In_ uint32_t TcpSeqNum,
diff --git a/src/platform/datapath_raw_socket.c b/src/platform/datapath_raw_socket.c
index 48f448e92d..d53ca7bf31 100644
--- a/src/platform/datapath_raw_socket.c
+++ b/src/platform/datapath_raw_socket.c
@@ -297,7 +297,7 @@ CxPlatDpRawParseIPv4(
         return;
     }
 
-    Packet->TypeOfService = IP->EcnField;
+    Packet->TypeOfService = IP->TypeOfServiceAndEcnField;
     Packet->HopLimitTTL = IP->TimeToLive;
     Packet->Route->RemoteAddress.Ipv4.sin_family = AF_INET;
     CxPlatCopyMemory(&Packet->Route->RemoteAddress.Ipv4.sin_addr, IP->Source, sizeof(IP->Source));
@@ -366,7 +366,7 @@ CxPlatDpRawParseIPv6(
     } VersionClassEcnFlow;
     VersionClassEcnFlow.Value = CxPlatByteSwapUint32(IP->VersionClassEcnFlow);
 
-    Packet->TypeOfService = (uint8_t)VersionClassEcnFlow.EcnField;
+    Packet->TypeOfService = ((uint8_t)VersionClassEcnFlow.EcnField) | (uint8_t)(VersionClassEcnFlow.Class << 2);
     Packet->HopLimitTTL = IP->HopLimit;
     Packet->Route->RemoteAddress.Ipv6.sin6_family = AF_INET6;
     CxPlatCopyMemory(&Packet->Route->RemoteAddress.Ipv6.sin6_addr, IP->Source, sizeof(IP->Source));
@@ -538,7 +538,7 @@ CxPlatDpRawSocketAckFin(
     CXPLAT_DBG_ASSERT(Socket->UseTcp);
 
     CXPLAT_ROUTE* Route = Packet->Route;
-    CXPLAT_SEND_CONFIG SendConfig = { Route, 0, CXPLAT_ECN_NON_ECT, 0 };
+    CXPLAT_SEND_CONFIG SendConfig = { Route, 0, CXPLAT_ECN_NON_ECT, 0, 0 };
     CXPLAT_SEND_DATA *SendData = CxPlatSendDataAlloc(CxPlatRawToSocket(Socket), &SendConfig);
     if (SendData == NULL) {
         return;
@@ -558,7 +558,7 @@ CxPlatDpRawSocketAckFin(
     TCP_HEADER* ReceivedTcpHeader = (TCP_HEADER*)(Packet->Buffer - Packet->ReservedEx);
 
     CxPlatFramingWriteHeaders(
-        Socket, Route, &SendData->Buffer, SendData->ECN,
+        Socket, Route, &SendData->Buffer, SendData->ECN, SendData->DSCP,
         Interface->OffloadStatus.Transmit.NetworkLayerXsum,
         Interface->OffloadStatus.Transmit.TransportLayerXsum,
         ReceivedTcpHeader->AckNumber,
@@ -577,7 +577,7 @@ CxPlatDpRawSocketAckSyn(
     CXPLAT_DBG_ASSERT(Socket->UseTcp);
 
     CXPLAT_ROUTE* Route = Packet->Route;
-    CXPLAT_SEND_CONFIG SendConfig = { Route, 0, CXPLAT_ECN_NON_ECT, 0 };
+    CXPLAT_SEND_CONFIG SendConfig = { Route, 0, CXPLAT_ECN_NON_ECT, 0, 0 };
     CXPLAT_SEND_DATA *SendData = CxPlatSendDataAlloc(CxPlatRawToSocket(Socket), &SendConfig);
     if (SendData == NULL) {
         return;
@@ -599,7 +599,7 @@ CxPlatDpRawSocketAckSyn(
         CASTED_CLOG_BYTEARRAY(sizeof(Route->LocalAddress), &Route->LocalAddress));
 
     CxPlatFramingWriteHeaders(
-        Socket, Route, &SendData->Buffer, SendData->ECN,
+        Socket, Route, &SendData->Buffer, SendData->ECN, SendData->DSCP,
         Interface->OffloadStatus.Transmit.NetworkLayerXsum,
         Interface->OffloadStatus.Transmit.TransportLayerXsum,
         ReceivedTcpHeader->AckNumber,
@@ -619,7 +619,7 @@ CxPlatDpRawSocketAckSyn(
             CASTED_CLOG_BYTEARRAY(sizeof(Route->RemoteAddress), &Route->RemoteAddress),
             CASTED_CLOG_BYTEARRAY(sizeof(Route->LocalAddress), &Route->LocalAddress));
         CxPlatFramingWriteHeaders(
-            Socket, Route, &SendData->Buffer, SendData->ECN,
+            Socket, Route, &SendData->Buffer, SendData->ECN, SendData->DSCP,
             Interface->OffloadStatus.Transmit.NetworkLayerXsum,
             Interface->OffloadStatus.Transmit.TransportLayerXsum,
             CxPlatByteSwapUint32(CxPlatByteSwapUint32(ReceivedTcpHeader->AckNumber) + 1),
@@ -642,7 +642,7 @@ CxPlatDpRawSocketAckSyn(
             CASTED_CLOG_BYTEARRAY(sizeof(Route->RemoteAddress), &Route->RemoteAddress),
             CASTED_CLOG_BYTEARRAY(sizeof(Route->LocalAddress), &Route->LocalAddress));
         CxPlatFramingWriteHeaders(
-            Socket, Route, &SendData->Buffer, SendData->ECN,
+            Socket, Route, &SendData->Buffer, SendData->ECN, SendData->DSCP,
             Interface->OffloadStatus.Transmit.NetworkLayerXsum,
             Interface->OffloadStatus.Transmit.TransportLayerXsum,
             ReceivedTcpHeader->AckNumber,
@@ -660,7 +660,7 @@ CxPlatDpRawSocketSyn(
     )
 {
     CXPLAT_DBG_ASSERT(Socket->UseTcp);
-    CXPLAT_SEND_CONFIG SendConfig = { (CXPLAT_ROUTE*)Route, 0, CXPLAT_ECN_NON_ECT, 0 };
+    CXPLAT_SEND_CONFIG SendConfig = { (CXPLAT_ROUTE*)Route, 0, CXPLAT_ECN_NON_ECT, 0, 0 };
     CXPLAT_SEND_DATA *SendData = CxPlatSendDataAlloc(CxPlatRawToSocket(Socket), &SendConfig);
     if (SendData == NULL) {
         return;
@@ -678,7 +678,7 @@ CxPlatDpRawSocketSyn(
     CXPLAT_DBG_ASSERT(Route->Queue != NULL);
     const CXPLAT_INTERFACE* Interface = CxPlatDpRawGetInterfaceFromQueue(Route->Queue);
     CxPlatFramingWriteHeaders(
-        Socket, Route, &SendData->Buffer, SendData->ECN,
+        Socket, Route, &SendData->Buffer, SendData->ECN, SendData->DSCP,
         Interface->OffloadStatus.Transmit.NetworkLayerXsum,
         Interface->OffloadStatus.Transmit.TransportLayerXsum,
         Route->TcpState.SequenceNumber, 0, TH_SYN);
@@ -692,6 +692,7 @@ CxPlatFramingWriteHeaders(
     _In_ const CXPLAT_ROUTE* Route,
     _Inout_ QUIC_BUFFER* Buffer,
     _In_ CXPLAT_ECN_TYPE ECN,
+    _In_ uint8_t DSCP,
     _In_ BOOLEAN SkipNetworkLayerXsum,
     _In_ BOOLEAN SkipTransportLayerXsum,
     _In_ uint32_t TcpSeqNum,
@@ -751,7 +752,7 @@ CxPlatFramingWriteHeaders(
     if (Family == QUIC_ADDRESS_FAMILY_INET) {
         IPV4_HEADER* IPv4 = (IPV4_HEADER*)(Transport - sizeof(IPV4_HEADER));
         IPv4->VersionAndHeaderLength = IPV4_DEFAULT_VERHLEN;
-        IPv4->TypeOfService = 0;
+        IPv4->TypeOfService = DSCP;
         IPv4->EcnField = ECN;
         IPv4->TotalLength = htons(sizeof(IPV4_HEADER) + TransportLength + (uint16_t)Buffer->Length);
         IPv4->Identification = 0;
@@ -799,7 +800,7 @@ CxPlatFramingWriteHeaders(
         } VersionClassEcnFlow = {0};
 
         VersionClassEcnFlow.Version = IPV6_VERSION;
-        VersionClassEcnFlow.Class = 0;
+        VersionClassEcnFlow.Class = DSCP;
         VersionClassEcnFlow.EcnField = ECN;
         VersionClassEcnFlow.Flow = (uint32_t)(uintptr_t)Socket;
 
diff --git a/src/platform/datapath_raw_xdp_linux.c b/src/platform/datapath_raw_xdp_linux.c
index 14471f91eb..0b45c993fe 100644
--- a/src/platform/datapath_raw_xdp_linux.c
+++ b/src/platform/datapath_raw_xdp_linux.c
@@ -1070,6 +1070,7 @@ CxPlatDpRawTxAlloc(
         Packet->Buffer.Length = Config->MaxPacketSize;
         Packet->Buffer.Buffer = &Packet->FrameBuffer[HeaderBackfill.AllLayer];
         Packet->ECN = Config->ECN;
+        Packet->DSCP = Config->DSCP;
         Packet->UmemRelativeAddr = BaseAddr;
         Packet->DatapathType = Config->Route->DatapathType = CXPLAT_DATAPATH_TYPE_RAW;
     }
diff --git a/src/platform/datapath_raw_xdp_win.c b/src/platform/datapath_raw_xdp_win.c
index c2178bfaf9..3fac60e6e2 100644
--- a/src/platform/datapath_raw_xdp_win.c
+++ b/src/platform/datapath_raw_xdp_win.c
@@ -1618,6 +1618,7 @@ CxPlatDpRawTxAlloc(
         Packet->Buffer.Length = Config->MaxPacketSize;
         Packet->Buffer.Buffer = &Packet->FrameBuffer[HeaderBackfill.AllLayer];
         Packet->ECN = Config->ECN;
+        Packet->DSCP = Config->DSCP;
         Packet->DatapathType = Config->Route->DatapathType = CXPLAT_DATAPATH_TYPE_RAW;
     }
 
diff --git a/src/platform/datapath_winkernel.c b/src/platform/datapath_winkernel.c
index 57d7862ea3..d933b80a18 100644
--- a/src/platform/datapath_winkernel.c
+++ b/src/platform/datapath_winkernel.c
@@ -471,7 +471,7 @@ CxPlatDataPathQuerySockoptSupport(
         Datapath->WskProviderNpi.Dispatch->
         WskSocket(
             Datapath->WskProviderNpi.Client,
-            AF_INET,
+            AF_INET6,
             SOCK_DGRAM,
             IPPROTO_UDP,
             WSK_FLAG_BASIC_SOCKET,
@@ -600,6 +600,54 @@ CxPlatDataPathQuerySockoptSupport(
 
     } while (FALSE);
 
+    do {
+        DWORD TypeOfService = 1; // Lower Effort
+
+        IoReuseIrp(Irp, STATUS_SUCCESS);
+        IoSetCompletionRoutine(
+            Irp,
+            CxPlatDataPathIoCompletion,
+            &CompletionEvent,
+            TRUE,
+            TRUE,
+            TRUE);
+        CxPlatEventReset(CompletionEvent);
+
+        Status =
+            Dispatch->WskControlSocket(
+                UdpSocket,
+                WskSetOption,
+                IPV6_TCLASS,
+                IPPROTO_IPV6,
+                sizeof(TypeOfService),
+                &TypeOfService,
+                0,
+                NULL,
+                &OutputSizeReturned,
+                Irp);
+        if (Status == STATUS_PENDING) {
+            CxPlatEventWaitForever(CompletionEvent);
+        } else if (QUIC_FAILED(Status)) {
+            QuicTraceLogWarning(
+                DatapathTestSetIpv6TrafficClassFailed,
+                "[data] Test setting IPV6_TCLASS failed, 0x%x",
+                Status);
+            break;
+        }
+
+        Status = Irp->IoStatus.Status;
+        if (QUIC_FAILED(Status)) {
+            QuicTraceLogWarning(
+                DatapathTestSetIpv6TrafficClassFailedAsync,
+                "[data] Test setting IPV6_TCLASS failed (async), 0x%x",
+                Status);
+            break;
+        }
+
+        Datapath->Features |= CXPLAT_DATAPATH_FEATURE_DSCP;
+
+    } while (FALSE);
+
     //
     // Some USO/URO bug blocks TTL feature support on Windows Server 2022.
     //
@@ -1441,7 +1489,7 @@ SocketCreateUdp(
         CxPlatDataPathSetControlSocket(
             Binding,
             WskSetOption,
-            IPV6_ECN,
+            IPV6_RECVTCLASS,
             IPPROTO_IPV6,
             sizeof(Option),
             &Option);
@@ -1451,7 +1499,7 @@ SocketCreateUdp(
             "[data][%p] ERROR, %u, %s.",
             Binding,
             Status,
-            "Set IPV6_ECN");
+            "Set IPV6_RECVTCLASS");
         goto Error;
     }
 
@@ -1460,7 +1508,7 @@ SocketCreateUdp(
         CxPlatDataPathSetControlSocket(
             Binding,
             WskSetOption,
-            IP_ECN,
+            IP_RECVTOS,
             IPPROTO_IP,
             sizeof(Option),
             &Option);
@@ -1470,7 +1518,7 @@ SocketCreateUdp(
             "[data][%p] ERROR, %u, %s.",
             Binding,
             Status,
-            "Set IP_ECN");
+            "Set IP_RECVTOS");
         goto Error;
     }
 
@@ -2022,7 +2070,7 @@ CxPlatDataPathSocketReceive(
         SOCKADDR_INET LocalAddr = { 0 };
         SOCKADDR_INET RemoteAddr;
         UINT16 MessageLength = 0;
-        INT ECN = 0;
+        INT TOS = 0;
         INT HopLimitTTL = 0;
 
         //
@@ -2052,9 +2100,9 @@ CxPlatDataPathSocketReceive(
                         IsUnreachableError = TRUE;
                         break;
                     }
-                } else if (CMsg->cmsg_type == IPV6_ECN) {
-                    ECN = *(PINT)WSA_CMSG_DATA(CMsg);
-                    CXPLAT_DBG_ASSERT(ECN < UINT8_MAX);
+                } else if (CMsg->cmsg_type == IPV6_TCLASS) {
+                    TOS = *(PINT)WSA_CMSG_DATA(CMsg);
+                    CXPLAT_DBG_ASSERT(TOS <= UINT8_MAX);
                 } else if (CMsg->cmsg_type == IPV6_HOPLIMIT) {
                     HopLimitTTL = *(PINT)WSA_CMSG_DATA(CMsg);
                     CXPLAT_DBG_ASSERT(HopLimitTTL < 256);
@@ -2075,9 +2123,9 @@ CxPlatDataPathSocketReceive(
                         IsUnreachableError = TRUE;
                         break;
                     }
-                } else if (CMsg->cmsg_type == IP_ECN) {
-                    ECN = *(PINT)WSA_CMSG_DATA(CMsg);
-                    CXPLAT_DBG_ASSERT(ECN < UINT8_MAX);
+                } else if (CMsg->cmsg_type == IP_TOS) {
+                    TOS = *(PINT)WSA_CMSG_DATA(CMsg);
+                    CXPLAT_DBG_ASSERT(TOS <= UINT8_MAX);
                 } else if (CMsg->cmsg_type == IP_TTL) {
                     HopLimitTTL = *(PINT)WSA_CMSG_DATA(CMsg);
                     CXPLAT_DBG_ASSERT(HopLimitTTL < 256);
@@ -2247,7 +2295,7 @@ CxPlatDataPathSocketReceive(
             Datagram->IoBlock = IoBlock;
             Datagram->Data.Next = NULL;
             Datagram->Data.PartitionIndex = (uint16_t)(CurProcNumber % Binding->Datapath->ProcCount);
-            Datagram->Data.TypeOfService = (uint8_t)ECN;
+            Datagram->Data.TypeOfService = (uint8_t)TOS;
             Datagram->Data.HopLimitTTL = (uint8_t)HopLimitTTL;
             Datagram->Data.Allocated = TRUE;
             Datagram->Data.QueuedOnConnection = FALSE;
@@ -2439,6 +2487,7 @@ SendDataAlloc(
     if (SendData != NULL) {
         SendData->Owner = ProcContext;
         SendData->ECN = Config->ECN;
+        SendData->DSCP = Config->DSCP;
         SendData->WskBufs = NULL;
         SendData->TailBuf = NULL;
         SendData->TotalSize = 0;
@@ -2881,6 +2930,7 @@ SocketSend(
     BYTE CMsgBuffer[
         WSA_CMSG_SPACE(sizeof(IN6_PKTINFO)) +   // IP_PKTINFO
         WSA_CMSG_SPACE(sizeof(INT)) +           // IP_ECN
+        WSA_CMSG_SPACE(sizeof(INT)) +           // IP_TOS/IPV6_TCLASS
         WSA_CMSG_SPACE(sizeof(*SegmentSize))    // UDP_SEND_MSG_SIZE
         ];
     PWSACMSGHDR CMsg = (PWSACMSGHDR)CMsgBuffer;
@@ -2923,6 +2973,18 @@ SocketSend(
         *(PINT)WSA_CMSG_DATA(CMsg) = SendData->ECN;
     }
 
+    if (Binding->Datapath->Features & CXPLAT_DATAPATH_FEATURE_DSCP) {
+        CMsg = (PWSACMSGHDR)&CMsgBuffer[CMsgLen];
+        CMsgLen += WSA_CMSG_SPACE(sizeof(INT));
+        CMsg->cmsg_level =
+            Route->LocalAddress.si_family == QUIC_ADDRESS_FAMILY_INET ?
+                IPPROTO_IP : IPPROTO_IPV6;
+        CMsg->cmsg_type =
+            Route->LocalAddress.si_family == QUIC_ADDRESS_FAMILY_INET ?
+                IP_TOS : IPV6_TCLASS;
+        CMsg->cmsg_len = WSA_CMSG_LEN(sizeof(INT));
+    }
+
     if (SendData->SegmentSize > 0) {
         CMsg = (PWSACMSGHDR)&CMsgBuffer[CMsgLen];
         CMsgLen += WSA_CMSG_SPACE(sizeof(*SegmentSize));
diff --git a/src/platform/datapath_winuser.c b/src/platform/datapath_winuser.c
index 946ceaf271..690114a286 100644
--- a/src/platform/datapath_winuser.c
+++ b/src/platform/datapath_winuser.c
@@ -163,7 +163,7 @@ typedef struct DATAPATH_RX_IO_BLOCK {
         RIO_CMSG_BASE_SIZE +
         WSA_CMSG_SPACE(sizeof(IN6_PKTINFO)) +   // IP_PKTINFO
         WSA_CMSG_SPACE(sizeof(DWORD)) +         // UDP_COALESCED_INFO
-        WSA_CMSG_SPACE(sizeof(INT)) +           // IP_ECN
+        WSA_CMSG_SPACE(sizeof(INT)) +           // IP_TOS
         WSA_CMSG_SPACE(sizeof(INT))             // IP_HOP_LIMIT
         ];
 
@@ -274,6 +274,7 @@ typedef struct CXPLAT_SEND_DATA {
         RIO_CMSG_BASE_SIZE +
         WSA_CMSG_SPACE(sizeof(IN6_PKTINFO)) +   // IP_PKTINFO
         WSA_CMSG_SPACE(sizeof(INT)) +           // IP_ECN
+        WSA_CMSG_SPACE(sizeof(INT)) +           // IP_TOS/IPV6_TCLASS
         WSA_CMSG_SPACE(sizeof(DWORD))           // UDP_SEND_MSG_SIZE
         ];
 
@@ -701,6 +702,41 @@ CxPlatDataPathQuerySockoptSupport(
     }
 }
 
+{
+    //
+    // Test ToS support with IPv6, because IPv4 just fails silently.
+    //
+    SOCKET Udpv6Socket = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
+    if (UdpSocket == INVALID_SOCKET) {
+        int WsaError = WSAGetLastError();
+        QuicTraceLogWarning(
+            DatapathOpenUdpv6SocketFailed,
+            "[data] UDPv6 helper socket failed to open, 0x%x",
+            WsaError);
+        goto Error;
+    }
+
+    DWORD TypeOfService = 1; // Lower Effort
+    OptionLength = sizeof(TypeOfService);
+    Result =
+        setsockopt(
+            Udpv6Socket,
+            IPPROTO_IPV6,
+            IPV6_TCLASS,
+            (char*)&TypeOfService,
+            sizeof(TypeOfService));
+    if (Result != NO_ERROR) {
+        int WsaError = WSAGetLastError();
+        QuicTraceLogWarning(
+            DatapathTestSetIpv6TrafficClassFailed,
+            "[data] Test setting IPV6_TCLASS failed, 0x%x",
+            WsaError);
+    } else {
+        Datapath->Features |= CXPLAT_DATAPATH_FEATURE_DSCP;
+    }
+    closesocket(Udpv6Socket);
+}
+
     //
     // Some USO/URO bug blocks TTL feature support on Windows Server 2022.
     //
@@ -1652,7 +1688,7 @@ SocketCreateUdp(
             setsockopt(
                 SocketProc->Socket,
                 IPPROTO_IPV6,
-                IPV6_ECN,
+                IPV6_RECVTCLASS,
                 (char*)&Option,
                 sizeof(Option));
         if (Result == SOCKET_ERROR) {
@@ -1662,7 +1698,7 @@ SocketCreateUdp(
                 "[data][%p] ERROR, %u, %s.",
                 Socket,
                 WsaError,
-                "Set IPV6_ECN");
+                "Set IPV6_RECVTCLASS");
             Status = HRESULT_FROM_WIN32(WsaError);
             goto Error;
         }
@@ -1672,7 +1708,7 @@ SocketCreateUdp(
             setsockopt(
                 SocketProc->Socket,
                 IPPROTO_IP,
-                IP_ECN,
+                IP_RECVTOS,
                 (char*)&Option,
                 sizeof(Option));
         if (Result == SOCKET_ERROR) {
@@ -1682,7 +1718,7 @@ SocketCreateUdp(
                 "[data][%p] ERROR, %u, %s.",
                 Socket,
                 WsaError,
-                "Set IP_ECN");
+                "Set IP_RECVTOS");
             Status = HRESULT_FROM_WIN32(WsaError);
             goto Error;
         }
@@ -3427,7 +3463,7 @@ CxPlatDataPathUdpRecvComplete(
         UINT16 MessageLength = NumberOfBytesTransferred;
         ULONG MessageCount = 0;
         BOOLEAN IsCoalesced = FALSE;
-        INT ECN = 0;
+        INT TOS = 0;
         INT HopLimitTTL = 0;
         if (SocketProc->Parent->UseRio) {
             PRIO_CMSG_BUFFER RioRcvMsg = (PRIO_CMSG_BUFFER)IoBlock->ControlBuf;
@@ -3448,9 +3484,9 @@ CxPlatDataPathUdpRecvComplete(
                     CxPlatConvertFromMappedV6(LocalAddr, LocalAddr);
                     LocalAddr->Ipv6.sin6_scope_id = PktInfo6->ipi6_ifindex;
                     FoundLocalAddr = TRUE;
-                } else if (CMsg->cmsg_type == IPV6_ECN) {
-                    ECN = *(PINT)WSA_CMSG_DATA(CMsg);
-                    CXPLAT_DBG_ASSERT(ECN < UINT8_MAX);
+                } else if (CMsg->cmsg_type == IPV6_TCLASS) {
+                    TOS = *(PINT)WSA_CMSG_DATA(CMsg);
+                    CXPLAT_DBG_ASSERT(TOS <= UINT8_MAX);
                 } else if (CMsg->cmsg_type == IPV6_HOPLIMIT) {
                     HopLimitTTL = *(PINT)WSA_CMSG_DATA(CMsg);
                     CXPLAT_DBG_ASSERT(HopLimitTTL < 256);
@@ -3464,9 +3500,9 @@ CxPlatDataPathUdpRecvComplete(
                     LocalAddr->Ipv4.sin_port = SocketProc->Parent->LocalAddress.Ipv6.sin6_port;
                     LocalAddr->Ipv6.sin6_scope_id = PktInfo->ipi_ifindex;
                     FoundLocalAddr = TRUE;
-                } else if (CMsg->cmsg_type == IP_ECN) {
-                    ECN = *(PINT)WSA_CMSG_DATA(CMsg);
-                    CXPLAT_DBG_ASSERT(ECN < UINT8_MAX);
+                } else if (CMsg->cmsg_type == IP_TOS) {
+                    TOS = *(PINT)WSA_CMSG_DATA(CMsg);
+                    CXPLAT_DBG_ASSERT(TOS <= UINT8_MAX);
                 } else if (CMsg->cmsg_type == IP_TTL) {
                     HopLimitTTL = *(PINT)WSA_CMSG_DATA(CMsg);
                     CXPLAT_DBG_ASSERT(HopLimitTTL < 256);
@@ -3527,7 +3563,7 @@ CxPlatDataPathUdpRecvComplete(
             Datagram->Route = &IoBlock->Route;
             Datagram->PartitionIndex =
                 SocketProc->DatapathProc->PartitionIndex % SocketProc->DatapathProc->Datapath->PartitionCount;
-            Datagram->TypeOfService = (uint8_t)ECN;
+            Datagram->TypeOfService = (uint8_t)TOS;
             Datagram->HopLimitTTL = (uint8_t) HopLimitTTL;
             Datagram->Allocated = TRUE;
             Datagram->Route->DatapathType = Datagram->DatapathType = CXPLAT_DATAPATH_TYPE_NORMAL;
@@ -4004,6 +4040,7 @@ SendDataAlloc(
         SendData->Owner = DatapathProc;
         SendData->SendDataPool = SendDataPool;
         SendData->ECN = Config->ECN;
+        SendData->DSCP = Config->DSCP;
         SendData->SendFlags = Config->Flags;
         SendData->SegmentSize =
             (Socket->Type != CXPLAT_SOCKET_UDP ||
@@ -4491,6 +4528,16 @@ CxPlatSocketSendInline(
         CMsg->cmsg_len = WSA_CMSG_LEN(sizeof(INT));
         *(PINT)WSA_CMSG_DATA(CMsg) = SendData->ECN;
 
+        if (Socket->Datapath->Features & CXPLAT_DATAPATH_FEATURE_DSCP) {
+            WSAMhdr.Control.len += WSA_CMSG_SPACE(sizeof(INT));
+            CMsg = WSA_CMSG_NXTHDR(&WSAMhdr, CMsg);
+            CXPLAT_DBG_ASSERT(CMsg != NULL);
+            CMsg->cmsg_level = IPPROTO_IP;
+            CMsg->cmsg_type = IP_TOS;
+            CMsg->cmsg_len = WSA_CMSG_LEN(sizeof(INT));
+            *(PINT)WSA_CMSG_DATA(CMsg) = SendData->DSCP;
+        }
+
     } else {
 
         if (!Socket->HasFixedRemoteAddress) {
@@ -4511,6 +4558,16 @@ CxPlatSocketSendInline(
         CMsg->cmsg_type = IPV6_ECN;
         CMsg->cmsg_len = WSA_CMSG_LEN(sizeof(INT));
         *(PINT)WSA_CMSG_DATA(CMsg) = SendData->ECN;
+
+        if (Socket->Datapath->Features & CXPLAT_DATAPATH_FEATURE_DSCP) {
+            WSAMhdr.Control.len += WSA_CMSG_SPACE(sizeof(INT));
+            CMsg = WSA_CMSG_NXTHDR(&WSAMhdr, CMsg);
+            CXPLAT_DBG_ASSERT(CMsg != NULL);
+            CMsg->cmsg_level = IPPROTO_IPV6;
+            CMsg->cmsg_type = IPV6_TCLASS;
+            CMsg->cmsg_len = WSA_CMSG_LEN(sizeof(INT));
+            *(PINT)WSA_CMSG_DATA(CMsg) = SendData->DSCP;
+        }
     }
 
     if (SendData->SegmentSize > 0) {
diff --git a/src/platform/pcp.c b/src/platform/pcp.c
index b91e6a54f6..e090b0bb17 100644
--- a/src/platform/pcp.c
+++ b/src/platform/pcp.c
@@ -391,7 +391,7 @@ CxPlatPcpSendMapRequestInternal(
     QUIC_ADDR LocalMappedAddress;
     CxPlatConvertToMappedV6(&Route.LocalAddress, &LocalMappedAddress);
 
-    CXPLAT_SEND_CONFIG SendConfig = { &Route, PCP_MAP_REQUEST_SIZE, CXPLAT_ECN_NON_ECT, 0 };
+    CXPLAT_SEND_CONFIG SendConfig = { &Route, PCP_MAP_REQUEST_SIZE, CXPLAT_ECN_NON_ECT, 0, 0 };
     CXPLAT_SEND_DATA* SendData = CxPlatSendDataAlloc(Socket, &SendConfig);
     if (SendData == NULL) {
         return QUIC_STATUS_OUT_OF_MEMORY;
@@ -483,7 +483,7 @@ CxPlatPcpSendPeerRequestInternal(
     QUIC_ADDR RemotePeerMappedAddress;
     CxPlatConvertToMappedV6(RemotePeerAddress, &RemotePeerMappedAddress);
 
-    CXPLAT_SEND_CONFIG SendConfig = { &Route, PCP_MAP_REQUEST_SIZE, CXPLAT_ECN_NON_ECT, 0 };
+    CXPLAT_SEND_CONFIG SendConfig = { &Route, PCP_MAP_REQUEST_SIZE, CXPLAT_ECN_NON_ECT, 0, 0 };
     CXPLAT_SEND_DATA* SendData = CxPlatSendDataAlloc(Socket, &SendConfig);
     if (SendData == NULL) {
         return QUIC_STATUS_OUT_OF_MEMORY;
diff --git a/src/platform/platform_internal.h b/src/platform/platform_internal.h
index 4930ceb614..78e2350c04 100644
--- a/src/platform/platform_internal.h
+++ b/src/platform/platform_internal.h
@@ -98,6 +98,11 @@ typedef struct CXPLAT_SEND_DATA_COMMON {
     //
     uint8_t ECN; // CXPLAT_ECN_TYPE
 
+    //
+    // The DSCP value to use for this send.
+    //
+    uint8_t DSCP;
+
     //
     // The total buffer size for WsaBuffers.
     //
diff --git a/src/platform/unittest/DataPathTest.cpp b/src/platform/unittest/DataPathTest.cpp
index f64d11e0c5..cbe8df2c90 100644
--- a/src/platform/unittest/DataPathTest.cpp
+++ b/src/platform/unittest/DataPathTest.cpp
@@ -86,7 +86,9 @@ struct UdpRecvContext {
     QUIC_ADDR DestinationAddress;
     CXPLAT_EVENT ClientCompletion;
     CXPLAT_ECN_TYPE EcnType {CXPLAT_ECN_NON_ECT};
+    uint8_t Dscp{0};
     bool TtlSupported;
+    bool DscpSupported;
     UdpRecvContext() {
         CxPlatEventInitialize(&ClientCompletion, FALSE, FALSE);
     }
@@ -299,11 +301,17 @@ struct DataPathTest : public ::testing::TestWithParam<int32_t>
                 ASSERT_EQ(0, RecvData->HopLimitTTL);
             }
 
+            if (RecvContext->DscpSupported) {
+                ASSERT_EQ(CXPLAT_DSCP_FROM_TOS(RecvData->TypeOfService), RecvContext->Dscp);
+            } else {
+                ASSERT_EQ(CXPLAT_DSCP_FROM_TOS(RecvData->TypeOfService), 0);
+            }
+
             if (RecvData->Route->LocalAddress.Ipv4.sin_port == RecvContext->DestinationAddress.Ipv4.sin_port) {
 
-                ASSERT_EQ((CXPLAT_ECN_TYPE)RecvData->TypeOfService, RecvContext->EcnType);
+                ASSERT_EQ(CXPLAT_ECN_FROM_TOS(RecvData->TypeOfService), RecvContext->EcnType);
 
-                CXPLAT_SEND_CONFIG SendConfig = { RecvData->Route, 0, (uint8_t)RecvContext->EcnType, 0 };
+                CXPLAT_SEND_CONFIG SendConfig = { RecvData->Route, 0, (uint8_t)RecvContext->EcnType, 0, RecvContext->Dscp };
                 auto ServerSendData = CxPlatSendDataAlloc(Socket, &SendConfig);
                 ASSERT_NE(nullptr, ServerSendData);
                 auto ServerBuffer = CxPlatSendDataAllocBuffer(ServerSendData, ExpectedDataSize);
@@ -782,9 +790,12 @@ TEST_P(DataPathTest, UdpData)
     UdpRecvContext RecvContext;
     CxPlatDataPath Datapath(&UdpRecvCallbacks);
     RecvContext.TtlSupported = Datapath.IsSupported(CXPLAT_DATAPATH_FEATURE_TTL);
+    RecvContext.DscpSupported = Datapath.IsSupported(CXPLAT_DATAPATH_FEATURE_DSCP);
     VERIFY_QUIC_SUCCESS(Datapath.GetInitStatus());
     ASSERT_NE(nullptr, Datapath.Datapath);
 
+    RecvContext.Dscp = RecvContext.DscpSupported ? 1 : 0;
+
     auto unspecAddress = GetNewUnspecAddr();
     CxPlatSocket Server(Datapath, &unspecAddress.SockAddr, nullptr, &RecvContext);
     while (Server.GetInitStatus() == QUIC_STATUS_ADDRESS_IN_USE) {
@@ -803,7 +814,7 @@ TEST_P(DataPathTest, UdpData)
     VERIFY_QUIC_SUCCESS(Client.GetInitStatus());
     ASSERT_NE(nullptr, Client.Socket);
 
-    CXPLAT_SEND_CONFIG SendConfig = { &Client.Route, 0, CXPLAT_ECN_NON_ECT, 0 };
+    CXPLAT_SEND_CONFIG SendConfig = { &Client.Route, 0, CXPLAT_ECN_NON_ECT, 0, RecvContext.Dscp };
     auto ClientSendData = CxPlatSendDataAlloc(Client, &SendConfig);
     ASSERT_NE(nullptr, ClientSendData);
     auto ClientBuffer = CxPlatSendDataAllocBuffer(ClientSendData, ExpectedDataSize);
@@ -820,9 +831,12 @@ TEST_P(DataPathTest, UdpDataPolling)
     UdpRecvContext RecvContext;
     CxPlatDataPath Datapath(&UdpRecvCallbacks, nullptr, 0, &Config);
     RecvContext.TtlSupported = Datapath.IsSupported(CXPLAT_DATAPATH_FEATURE_TTL);
+    RecvContext.DscpSupported = Datapath.IsSupported(CXPLAT_DATAPATH_FEATURE_DSCP);
     VERIFY_QUIC_SUCCESS(Datapath.GetInitStatus());
     ASSERT_NE(nullptr, Datapath.Datapath);
 
+    RecvContext.Dscp = RecvContext.DscpSupported ? 1 : 0;
+
     auto unspecAddress = GetNewUnspecAddr();
     CxPlatSocket Server(Datapath, &unspecAddress.SockAddr, nullptr, &RecvContext);
     while (Server.GetInitStatus() == QUIC_STATUS_ADDRESS_IN_USE) {
@@ -841,7 +855,7 @@ TEST_P(DataPathTest, UdpDataPolling)
     VERIFY_QUIC_SUCCESS(Client.GetInitStatus());
     ASSERT_NE(nullptr, Client.Socket);
 
-    CXPLAT_SEND_CONFIG SendConfig = { &Client.Route, 0, CXPLAT_ECN_NON_ECT, 0 };
+    CXPLAT_SEND_CONFIG SendConfig = { &Client.Route, 0, CXPLAT_ECN_NON_ECT, 0, RecvContext.Dscp };
     auto ClientSendData = CxPlatSendDataAlloc(Client, &SendConfig);
     ASSERT_NE(nullptr, ClientSendData);
     auto ClientBuffer = CxPlatSendDataAllocBuffer(ClientSendData, ExpectedDataSize);
@@ -857,9 +871,12 @@ TEST_P(DataPathTest, UdpDataRebind)
     UdpRecvContext RecvContext;
     CxPlatDataPath Datapath(&UdpRecvCallbacks);
     RecvContext.TtlSupported = Datapath.IsSupported(CXPLAT_DATAPATH_FEATURE_TTL);
+    RecvContext.DscpSupported = Datapath.IsSupported(CXPLAT_DATAPATH_FEATURE_DSCP);
     VERIFY_QUIC_SUCCESS(Datapath.GetInitStatus());
     ASSERT_NE(nullptr, Datapath.Datapath);
 
+    RecvContext.Dscp = RecvContext.DscpSupported ? 1 : 0;
+
     auto unspecAddress = GetNewUnspecAddr();
     CxPlatSocket Server(Datapath, &unspecAddress.SockAddr, nullptr, &RecvContext);
     while (Server.GetInitStatus() == QUIC_STATUS_ADDRESS_IN_USE) {
@@ -879,7 +896,7 @@ TEST_P(DataPathTest, UdpDataRebind)
         VERIFY_QUIC_SUCCESS(Client.GetInitStatus());
         ASSERT_NE(nullptr, Client.Socket);
 
-        CXPLAT_SEND_CONFIG SendConfig = { &Client.Route, 0, CXPLAT_ECN_NON_ECT, 0 };
+        CXPLAT_SEND_CONFIG SendConfig = { &Client.Route, 0, CXPLAT_ECN_NON_ECT, 0, RecvContext.Dscp };
         auto ClientSendData = CxPlatSendDataAlloc(Client, &SendConfig);
         ASSERT_NE(nullptr, ClientSendData);
         auto ClientBuffer = CxPlatSendDataAllocBuffer(ClientSendData, ExpectedDataSize);
@@ -896,7 +913,7 @@ TEST_P(DataPathTest, UdpDataRebind)
         VERIFY_QUIC_SUCCESS(Client.GetInitStatus());
         ASSERT_NE(nullptr, Client.Socket);
 
-        CXPLAT_SEND_CONFIG SendConfig = { &Client.Route, 0, CXPLAT_ECN_NON_ECT, 0 };
+        CXPLAT_SEND_CONFIG SendConfig = { &Client.Route, 0, CXPLAT_ECN_NON_ECT, 0, RecvContext.Dscp };
         auto ClientSendData = CxPlatSendDataAlloc(Client, &SendConfig);
         ASSERT_NE(nullptr, ClientSendData);
         auto ClientBuffer = CxPlatSendDataAllocBuffer(ClientSendData, ExpectedDataSize);
@@ -914,9 +931,12 @@ TEST_P(DataPathTest, UdpDataECT0)
     RecvContext.EcnType = CXPLAT_ECN_ECT_0;
     CxPlatDataPath Datapath(&UdpRecvCallbacks);
     RecvContext.TtlSupported = Datapath.IsSupported(CXPLAT_DATAPATH_FEATURE_TTL);
+    RecvContext.DscpSupported = Datapath.IsSupported(CXPLAT_DATAPATH_FEATURE_DSCP);
     VERIFY_QUIC_SUCCESS(Datapath.GetInitStatus());
     ASSERT_NE(nullptr, Datapath.Datapath);
 
+    RecvContext.Dscp = RecvContext.DscpSupported ? 1 : 0;
+
     auto unspecAddress = GetNewUnspecAddr();
     CxPlatSocket Server(Datapath, &unspecAddress.SockAddr, nullptr, &RecvContext);
     while (Server.GetInitStatus() == QUIC_STATUS_ADDRESS_IN_USE) {
@@ -935,7 +955,7 @@ TEST_P(DataPathTest, UdpDataECT0)
     VERIFY_QUIC_SUCCESS(Client.GetInitStatus());
     ASSERT_NE(nullptr, Client.Socket);
 
-    CXPLAT_SEND_CONFIG SendConfig = { &Client.Route, 0, CXPLAT_ECN_ECT_0, 0 };
+    CXPLAT_SEND_CONFIG SendConfig = { &Client.Route, 0, CXPLAT_ECN_ECT_0, 0, RecvContext.Dscp };
     auto ClientSendData = CxPlatSendDataAlloc(Client, &SendConfig);
     ASSERT_NE(nullptr, ClientSendData);
     auto ClientBuffer = CxPlatSendDataAllocBuffer(ClientSendData, ExpectedDataSize);
@@ -951,6 +971,7 @@ TEST_P(DataPathTest, UdpShareClientSocket)
     UdpRecvContext RecvContext;
     CxPlatDataPath Datapath(&UdpRecvCallbacks);
     RecvContext.TtlSupported = Datapath.IsSupported(CXPLAT_DATAPATH_FEATURE_TTL);
+    RecvContext.DscpSupported = Datapath.IsSupported(CXPLAT_DATAPATH_FEATURE_DSCP);
     VERIFY_QUIC_SUCCESS(Datapath.GetInitStatus());
     ASSERT_NE(nullptr, Datapath.Datapath);
     // TODO: Linux XDP (duonic) to support port sharing
@@ -959,6 +980,8 @@ TEST_P(DataPathTest, UdpShareClientSocket)
         return;
     }
 
+    RecvContext.Dscp = RecvContext.DscpSupported ? 1 : 0;
+
     auto serverAddress = GetNewLocalAddr();
     CxPlatSocket Server1(Datapath, &serverAddress.SockAddr, nullptr, &RecvContext);
     while (Server1.GetInitStatus() == QUIC_STATUS_ADDRESS_IN_USE) {
@@ -984,7 +1007,7 @@ TEST_P(DataPathTest, UdpShareClientSocket)
     CxPlatSocket Client2(Datapath, &clientAddress, &serverAddress.SockAddr, &RecvContext, CXPLAT_SOCKET_FLAG_SHARE);
     VERIFY_QUIC_SUCCESS(Client2.GetInitStatus());
 
-    CXPLAT_SEND_CONFIG SendConfig = { &Client1.Route, 0, CXPLAT_ECN_NON_ECT, 0 };
+    CXPLAT_SEND_CONFIG SendConfig = { &Client1.Route, 0, CXPLAT_ECN_NON_ECT, 0, RecvContext.Dscp };
     auto ClientSendData = CxPlatSendDataAlloc(Client1, &SendConfig);
     ASSERT_NE(nullptr, ClientSendData);
     auto ClientBuffer = CxPlatSendDataAllocBuffer(ClientSendData, ExpectedDataSize);
@@ -996,7 +1019,7 @@ TEST_P(DataPathTest, UdpShareClientSocket)
     ASSERT_TRUE(CxPlatEventWaitWithTimeout(RecvContext.ClientCompletion, 2000));
     CxPlatEventReset(RecvContext.ClientCompletion);
 
-    CXPLAT_SEND_CONFIG SendConfig2 = { &Client2.Route, 0, CXPLAT_ECN_NON_ECT, 0 };
+    CXPLAT_SEND_CONFIG SendConfig2 = { &Client2.Route, 0, CXPLAT_ECN_NON_ECT, 0, RecvContext.Dscp };
     ClientSendData = CxPlatSendDataAlloc(Client2, &SendConfig2);
     ASSERT_NE(nullptr, ClientSendData);
     ClientBuffer = CxPlatSendDataAllocBuffer(ClientSendData, ExpectedDataSize);
@@ -1035,6 +1058,7 @@ TEST_P(DataPathTest, MultiBindListenerSingleProcessor) {
     QUIC_EXECUTION_CONFIG Config = { QUIC_EXECUTION_CONFIG_FLAG_NO_IDEAL_PROC, UINT32_MAX, 1, 0 };
     CxPlatDataPath Datapath(&UdpRecvCallbacks, nullptr, 0, &Config);
     RecvContext.TtlSupported = Datapath.IsSupported(CXPLAT_DATAPATH_FEATURE_TTL);
+    RecvContext.DscpSupported = Datapath.IsSupported(CXPLAT_DATAPATH_FEATURE_DSCP);
 
     auto ServerAddress = GetNewLocalAddr();
     CxPlatSocket Server1(Datapath, &ServerAddress.SockAddr, nullptr, &RecvContext);
@@ -1211,7 +1235,7 @@ TEST_P(DataPathTest, TcpDataClient)
     ASSERT_TRUE(CxPlatEventWaitWithTimeout(ListenerContext.AcceptEvent, 500));
     ASSERT_NE(nullptr, ListenerContext.Server);
 
-    CXPLAT_SEND_CONFIG SendConfig = { &Client.Route, 0, CXPLAT_ECN_NON_ECT, 0 };
+    CXPLAT_SEND_CONFIG SendConfig = { &Client.Route, 0, CXPLAT_ECN_NON_ECT, 0, 0 };
     auto SendData = CxPlatSendDataAlloc(Client, &SendConfig);
     ASSERT_NE(nullptr, SendData);
     auto SendBuffer = CxPlatSendDataAllocBuffer(SendData, ExpectedDataSize);
@@ -1256,7 +1280,7 @@ TEST_P(DataPathTest, TcpDataServer)
     CXPLAT_ROUTE Route = Listener.Route;
     Route.RemoteAddress = Client.GetLocalAddress();
 
-    CXPLAT_SEND_CONFIG SendConfig = { &Route, 0, CXPLAT_ECN_NON_ECT, 0 };
+    CXPLAT_SEND_CONFIG SendConfig = { &Route, 0, CXPLAT_ECN_NON_ECT, 0, 0 };
     auto SendData = CxPlatSendDataAlloc(ListenerContext.Server, &SendConfig);
     ASSERT_NE(nullptr, SendData);
     auto SendBuffer = CxPlatSendDataAllocBuffer(SendData, ExpectedDataSize);
diff --git a/src/test/lib/QuicDrill.cpp b/src/test/lib/QuicDrill.cpp
index 407f0f2caf..ccc51dcd5d 100644
--- a/src/test/lib/QuicDrill.cpp
+++ b/src/test/lib/QuicDrill.cpp
@@ -205,7 +205,7 @@ struct DrillSender {
         CxPlatSocketGetLocalAddress(Binding, &Route.LocalAddress);
         Route.RemoteAddress = ServerAddress;
 
-        CXPLAT_SEND_CONFIG SendConfig = { &Route, DatagramLength, CXPLAT_ECN_NON_ECT, 0 };
+        CXPLAT_SEND_CONFIG SendConfig = { &Route, DatagramLength, CXPLAT_ECN_NON_ECT, 0, 0 };
 
         CXPLAT_SEND_DATA* SendData = CxPlatSendDataAlloc(Binding, &SendConfig);
 
diff --git a/src/tools/attack/attack.cpp b/src/tools/attack/attack.cpp
index 92428cec6f..c6da0c094d 100644
--- a/src/tools/attack/attack.cpp
+++ b/src/tools/attack/attack.cpp
@@ -173,7 +173,7 @@ void RunAttackRandom(CXPLAT_SOCKET* Binding, uint16_t DatagramLength, bool Valid
             continue;
         }
 
-        CXPLAT_SEND_CONFIG SendConfig = {&Route, DatagramLength, CXPLAT_ECN_NON_ECT, 0 };
+        CXPLAT_SEND_CONFIG SendConfig = {&Route, DatagramLength, CXPLAT_ECN_NON_ECT, 0, 0 };
         CXPLAT_SEND_DATA* SendData = CxPlatSendDataAlloc(Binding, &SendConfig);
         if (SendData == nullptr) {
             continue;
@@ -288,7 +288,7 @@ void RunAttackValidInitial(CXPLAT_SOCKET* Binding)
             continue;
         }
 
-        CXPLAT_SEND_CONFIG SendConfig = {&Route, DatagramLength, CXPLAT_ECN_NON_ECT, 0 };
+        CXPLAT_SEND_CONFIG SendConfig = {&Route, DatagramLength, CXPLAT_ECN_NON_ECT, 0, 0 };
         CXPLAT_SEND_DATA* SendData = CxPlatSendDataAlloc(Binding, &SendConfig);
         if (SendData == nullptr) {
             continue;
diff --git a/src/tools/lb/loadbalancer.cpp b/src/tools/lb/loadbalancer.cpp
index e87ec0cc20..77be480eef 100644
--- a/src/tools/lb/loadbalancer.cpp
+++ b/src/tools/lb/loadbalancer.cpp
@@ -66,7 +66,7 @@ struct LbInterface {
         Route.LocalAddress = LocalAddress;
         Route.RemoteAddress = *PeerAddress;
         CXPLAT_SEND_DATA* Send = nullptr;
-        CXPLAT_SEND_CONFIG SendConfig = { &Route, MAX_UDP_PAYLOAD_LENGTH, CXPLAT_ECN_NON_ECT, 0 };
+        CXPLAT_SEND_CONFIG SendConfig = { &Route, MAX_UDP_PAYLOAD_LENGTH, CXPLAT_ECN_NON_ECT, 0, 0 };
         while (RecvDataChain) {
             if (!Send) {
                 Send = CxPlatSendDataAlloc(Socket, &SendConfig);
diff --git a/src/tools/recvfuzz/recvfuzz.cpp b/src/tools/recvfuzz/recvfuzz.cpp
index 178fb00e97..32a99246de 100644
--- a/src/tools/recvfuzz/recvfuzz.cpp
+++ b/src/tools/recvfuzz/recvfuzz.cpp
@@ -591,7 +591,7 @@ void sendPacket(
     bool fuzzing = true,
     TlsContext* ClientContext = nullptr) {
     const uint16_t DatagramLength = QUIC_MIN_INITIAL_LENGTH;
-    CXPLAT_SEND_CONFIG SendConfig = { &Route, DatagramLength, CXPLAT_ECN_NON_ECT, 0 };
+    CXPLAT_SEND_CONFIG SendConfig = { &Route, DatagramLength, CXPLAT_ECN_NON_ECT, 0, 0 };
     CXPLAT_SEND_DATA* SendData = CxPlatSendDataAlloc(Binding, &SendConfig);
     if (!SendData) {
         printf("CxPlatSendDataAlloc failed\n");