diff --git a/lib/netty b/lib/netty
index e36c1436b8..a7d1dc362a 160000
--- a/lib/netty
+++ b/lib/netty
@@ -1 +1 @@
-Subproject commit e36c1436b80399175fad55d09848c9f29da2174e
+Subproject commit a7d1dc362ae0ab5998723aae120b36d606a31425
diff --git a/netty/src/main/java/io/grpc/transport/netty/NettyClientHandler.java b/netty/src/main/java/io/grpc/transport/netty/NettyClientHandler.java
index ebfb381a54..55f2d0cf98 100644
--- a/netty/src/main/java/io/grpc/transport/netty/NettyClientHandler.java
+++ b/netty/src/main/java/io/grpc/transport/netty/NettyClientHandler.java
@@ -167,7 +167,7 @@ class NettyClientHandler extends Http2ConnectionHandler {
 
   private void onHeadersRead(int streamId, Http2Headers headers, boolean endStream)
       throws Http2Exception {
-    NettyClientStream stream = clientStream(connection().requireStream(streamId));
+    NettyClientStream stream = clientStream(requireHttp2Stream(streamId));
     stream.transportHeadersReceived(headers, endStream);
   }
 
@@ -175,8 +175,7 @@ class NettyClientHandler extends Http2ConnectionHandler {
    * Handler for an inbound HTTP/2 DATA frame.
    */
   private void onDataRead(int streamId, ByteBuf data, boolean endOfStream) throws Http2Exception {
-    Http2Stream http2Stream = connection().requireStream(streamId);
-    NettyClientStream stream = clientStream(http2Stream);
+    NettyClientStream stream = clientStream(requireHttp2Stream(streamId));
     stream.transportDataReceived(data, endOfStream);
   }
 
@@ -186,8 +185,7 @@ class NettyClientHandler extends Http2ConnectionHandler {
   private void onRstStreamRead(int streamId)
       throws Http2Exception {
     // TODO(nmittler): do something with errorCode?
-    Http2Stream http2Stream = connection().requireStream(streamId);
-    NettyClientStream stream = clientStream(http2Stream);
+    NettyClientStream stream = clientStream(requireHttp2Stream(streamId));
     stream.transportReportStatus(Status.UNKNOWN, false, new Metadata.Trailers());
   }
 
@@ -360,15 +358,24 @@ class NettyClientHandler extends Http2ConnectionHandler {
     return id;
   }
 
+  private Http2Stream requireHttp2Stream(int streamId) {
+    Http2Stream stream = connection().stream(streamId);
+    if (stream == null) {
+      // This should never happen.
+      throw new AssertionError("Stream does not exist: " + streamId);
+    }
+    return stream;
+  }
+
   /**
    * Initializes the connection window if we haven't already.
    */
   private void initConnectionWindow() throws Http2Exception {
     if (connectionWindowSize > 0 && ctx.channel().isActive()) {
-      Http2Stream stream = connection().connectionStream();
-      int currentSize = decoder().flowController().windowSize(stream);
+      Http2Stream connectionStream = connection().connectionStream();
+      int currentSize = connectionStream.localFlowState().windowSize();
       int delta = connectionWindowSize - currentSize;
-      decoder().flowController().incrementWindowSize(ctx, stream, delta);
+      decoder().flowController().incrementWindowSize(ctx, connectionStream, delta);
       connectionWindowSize = -1;
     }
   }
diff --git a/netty/src/main/java/io/grpc/transport/netty/NettyServerHandler.java b/netty/src/main/java/io/grpc/transport/netty/NettyServerHandler.java
index 0481e0036f..89fca0017f 100644
--- a/netty/src/main/java/io/grpc/transport/netty/NettyServerHandler.java
+++ b/netty/src/main/java/io/grpc/transport/netty/NettyServerHandler.java
@@ -136,7 +136,7 @@ class NettyServerHandler extends Http2ConnectionHandler {
     try {
       // The Http2Stream object was put by AbstractHttp2ConnectionHandler before calling this
       // method.
-      Http2Stream http2Stream = connection().requireStream(streamId);
+      Http2Stream http2Stream = requireHttp2Stream(streamId);
       NettyServerStream stream = new NettyServerStream(ctx.channel(), http2Stream, this);
       http2Stream.setProperty(NettyServerStream.class, stream);
       String method = determineMethod(streamId, headers);
@@ -153,10 +153,8 @@ class NettyServerHandler extends Http2ConnectionHandler {
 
   private void onDataRead(int streamId, ByteBuf data, boolean endOfStream) throws Http2Exception {
     try {
-      NettyServerStream stream = serverStream(connection().requireStream(streamId));
+      NettyServerStream stream = serverStream(requireHttp2Stream(streamId));
       stream.inboundDataReceived(data, endOfStream);
-    } catch (Http2Exception e) {
-      throw e;
     } catch (Throwable e) {
       logger.log(Level.WARNING, "Exception in onDataRead()", e);
       throw newStreamException(streamId, e);
@@ -165,10 +163,8 @@ class NettyServerHandler extends Http2ConnectionHandler {
 
   private void onRstStreamRead(int streamId) throws Http2Exception {
     try {
-      NettyServerStream stream = serverStream(connection().requireStream(streamId));
+      NettyServerStream stream = serverStream(requireHttp2Stream(streamId));
       stream.abortStream(Status.CANCELLED, false);
-    } catch (Http2Exception e) {
-      throw e;
     } catch (Throwable e) {
       logger.log(Level.WARNING, "Exception in onRstStreamRead()", e);
       throw newStreamException(streamId, e);
@@ -249,7 +245,7 @@ class NettyServerHandler extends Http2ConnectionHandler {
   }
 
   private void closeStreamWhenDone(ChannelPromise promise, int streamId) throws Http2Exception {
-    final NettyServerStream stream = serverStream(connection().requireStream(streamId));
+    final NettyServerStream stream = serverStream(requireHttp2Stream(streamId));
     promise.addListener(new ChannelFutureListener() {
       @Override
       public void operationComplete(ChannelFuture future) {
@@ -307,6 +303,15 @@ class NettyServerHandler extends Http2ConnectionHandler {
     });
   }
 
+  private Http2Stream requireHttp2Stream(int streamId) {
+    Http2Stream stream = connection().stream(streamId);
+    if (stream == null) {
+      // This should never happen.
+      throw new AssertionError("Stream does not exist: " + streamId);
+    }
+    return stream;
+  }
+
   private String determineMethod(int streamId, Http2Headers headers) throws Http2Exception {
     if (!HTTP_METHOD.equals(headers.method())) {
       throw Http2Exception.streamError(streamId, Http2Error.REFUSED_STREAM,
diff --git a/netty/src/test/java/io/grpc/transport/netty/NettyClientHandlerTest.java b/netty/src/test/java/io/grpc/transport/netty/NettyClientHandlerTest.java
index 80ca50a6b3..33ea779c1c 100644
--- a/netty/src/test/java/io/grpc/transport/netty/NettyClientHandlerTest.java
+++ b/netty/src/test/java/io/grpc/transport/netty/NettyClientHandlerTest.java
@@ -357,8 +357,8 @@ public class NettyClientHandlerTest extends NettyHandlerTestBase {
     int connectionWindow = 1048576; // 1MiB
     handler = newHandler(connectionWindow, DEFAULT_WINDOW_SIZE);
     handler.handlerAdded(ctx);
-    assertEquals(connectionWindow,
-        handler.decoder().flowController().windowSize(handler.connection().connectionStream()));
+    assertEquals(connectionWindow, handler.connection().connectionStream().localFlowState()
+        .windowSize());
   }
 
   @Test