diff --git a/jvm/core/src/main/java/ml/dmlc/tvm/rpc/ConnectProxyServerProcessor.java b/jvm/core/src/main/java/ml/dmlc/tvm/rpc/ConnectProxyServerProcessor.java
index 2fc97f65aca4..04888f568be3 100644
--- a/jvm/core/src/main/java/ml/dmlc/tvm/rpc/ConnectProxyServerProcessor.java
+++ b/jvm/core/src/main/java/ml/dmlc/tvm/rpc/ConnectProxyServerProcessor.java
@@ -30,7 +30,6 @@ public class ConnectProxyServerProcessor implements ServerProcessor {
   private final String host;
   private final int port;
   private final String key;
-  private final SocketFileDescriptorGetter socketFileDescriptorGetter;
 
   private volatile Socket currSocket = new Socket();
   private Runnable callback;
@@ -40,14 +39,11 @@ public class ConnectProxyServerProcessor implements ServerProcessor {
    * @param host Proxy server host.
    * @param port Proxy server port.
    * @param key Proxy server key.
-   * @param sockFdGetter Method to get file descriptor from Java socket.
    */
-  public ConnectProxyServerProcessor(String host, int port, String key,
-      SocketFileDescriptorGetter sockFdGetter) {
+  public ConnectProxyServerProcessor(String host, int port, String key) {
     this.host = host;
     this.port = port;
     this.key = "server:" + key;
-    socketFileDescriptorGetter = sockFdGetter;
   }
   
   /** 
@@ -70,8 +66,8 @@ public void setStartTimeCallback(Runnable callback) {
     try {
       SocketAddress address = new InetSocketAddress(host, port);
       currSocket.connect(address, 6000);
-      InputStream in = currSocket.getInputStream();
-      OutputStream out = currSocket.getOutputStream();
+      final InputStream in = currSocket.getInputStream();
+      final OutputStream out = currSocket.getOutputStream();
       out.write(Utils.toBytes(RPC.RPC_MAGIC));
       out.write(Utils.toBytes(key.length()));
       out.write(Utils.toBytes(key));
@@ -91,11 +87,10 @@ public void setStartTimeCallback(Runnable callback) {
       if (callback != null) {
         callback.run();
       }
-      final int sockFd = socketFileDescriptorGetter.get(currSocket);
-      if (sockFd != -1) {
-        new NativeServerLoop(sockFd).run();
-        System.err.println("Finish serving " + address);
-      }
+
+      SocketChannel sockChannel = new SocketChannel(currSocket);
+      new NativeServerLoop(sockChannel.getFsend(), sockChannel.getFrecv()).run();
+      System.err.println("Finish serving " + address);
     } catch (Throwable e) {
       e.printStackTrace();
       throw new RuntimeException(e);
diff --git a/jvm/core/src/main/java/ml/dmlc/tvm/rpc/ConnectTrackerServerProcessor.java b/jvm/core/src/main/java/ml/dmlc/tvm/rpc/ConnectTrackerServerProcessor.java
index 47881eb350c3..c449bb18a565 100644
--- a/jvm/core/src/main/java/ml/dmlc/tvm/rpc/ConnectTrackerServerProcessor.java
+++ b/jvm/core/src/main/java/ml/dmlc/tvm/rpc/ConnectTrackerServerProcessor.java
@@ -37,7 +37,6 @@
  */
 public class ConnectTrackerServerProcessor implements ServerProcessor {
   private ServerSocket server;
-  private final SocketFileDescriptorGetter socketFileDescriptorGetter;
   private final String trackerHost;
   private final int trackerPort;
   // device key
@@ -62,10 +61,11 @@ public class ConnectTrackerServerProcessor implements ServerProcessor {
    * @param trackerHost Tracker host.
    * @param trackerPort Tracker port.
    * @param key Device key.
-   * @param sockFdGetter Method to get file descriptor from Java socket.
+   * @param watchdog watch for timeout, etc.
+   * @throws java.io.IOException when socket fails to open.
    */
   public ConnectTrackerServerProcessor(String trackerHost, int trackerPort, String key,
-      SocketFileDescriptorGetter sockFdGetter, RPCWatchdog watchdog) throws IOException {
+      RPCWatchdog watchdog) throws IOException {
     while (true) {
       try {
         this.server = new ServerSocket(serverPort);
@@ -81,7 +81,6 @@ public ConnectTrackerServerProcessor(String trackerHost, int trackerPort, String
       }
     }
     System.err.println("using port: " + serverPort);
-    this.socketFileDescriptorGetter = sockFdGetter;
     this.trackerHost = trackerHost;
     this.trackerPort = trackerPort;
     this.key = key;
@@ -163,11 +162,9 @@ public String getMatchKey() {
       System.err.println("Connection from " + socket.getRemoteSocketAddress().toString());
       // received timeout in seconds
       watchdog.startTimeout(timeout * 1000);
-      final int sockFd = socketFileDescriptorGetter.get(socket);
-      if (sockFd != -1) {
-        new NativeServerLoop(sockFd).run();
-        System.err.println("Finish serving " + socket.getRemoteSocketAddress().toString());
-      }
+      SocketChannel sockChannel = new SocketChannel(socket);
+      new NativeServerLoop(sockChannel.getFsend(), sockChannel.getFrecv()).run();
+      System.err.println("Finish serving " + socket.getRemoteSocketAddress().toString());
       Utils.closeQuietly(socket);
     } catch (ConnectException e) {
       // if the tracker connection failed, wait a bit before retrying
diff --git a/jvm/core/src/main/java/ml/dmlc/tvm/rpc/NativeServerLoop.java b/jvm/core/src/main/java/ml/dmlc/tvm/rpc/NativeServerLoop.java
index 255dabb438d5..697ce45fa04f 100644
--- a/jvm/core/src/main/java/ml/dmlc/tvm/rpc/NativeServerLoop.java
+++ b/jvm/core/src/main/java/ml/dmlc/tvm/rpc/NativeServerLoop.java
@@ -28,14 +28,17 @@
  * Call native ServerLoop on socket file descriptor.
  */
 public class NativeServerLoop implements Runnable {
-  private final int sockFd;
+  private final Function fsend;
+  private final Function frecv;
 
   /**
    * Constructor for NativeServerLoop.
-   * @param nativeSockFd native socket file descriptor.
+   * @param fsend socket.send function.
+   * @param frecv socket.recv function.
    */
-  public NativeServerLoop(final int nativeSockFd) {
-    sockFd = nativeSockFd;
+  public NativeServerLoop(final Function fsend, final Function frecv) {
+    this.fsend = fsend;
+    this.frecv = frecv;
   }
 
   @Override public void run() {
@@ -43,7 +46,7 @@ public NativeServerLoop(final int nativeSockFd) {
     try {
       tempDir = serverEnv();
       System.err.println("starting server loop...");
-      RPC.getApi("_ServerLoop").pushArg(sockFd).invoke();
+      RPC.getApi("_ServerLoop").pushArg(fsend).pushArg(frecv).invoke();
       System.err.println("done server loop...");
     } catch (IOException e) {
       e.printStackTrace();
diff --git a/jvm/core/src/main/java/ml/dmlc/tvm/rpc/RPCSession.java b/jvm/core/src/main/java/ml/dmlc/tvm/rpc/RPCSession.java
index 8ebf188b0667..278ef9fe8eef 100644
--- a/jvm/core/src/main/java/ml/dmlc/tvm/rpc/RPCSession.java
+++ b/jvm/core/src/main/java/ml/dmlc/tvm/rpc/RPCSession.java
@@ -200,6 +200,7 @@ public void upload(byte[] data, String target) {
    * Upload file to remote runtime temp folder.
    * @param data The file in local to upload.
    * @param target The path in remote.
+   * @throws java.io.IOException for network failure.
    */
   public void upload(File data, String target) throws IOException {
     byte[] blob = getBytesFromFile(data);
@@ -209,6 +210,7 @@ public void upload(File data, String target) throws IOException {
   /**
    * Upload file to remote runtime temp folder.
    * @param data The file in local to upload.
+   * @throws java.io.IOException for network failure.
    */
   public void upload(File data) throws IOException {
     upload(data, data.getName());
diff --git a/jvm/core/src/main/java/ml/dmlc/tvm/rpc/Server.java b/jvm/core/src/main/java/ml/dmlc/tvm/rpc/Server.java
index c81faa0ca999..a9ea2d89a62c 100644
--- a/jvm/core/src/main/java/ml/dmlc/tvm/rpc/Server.java
+++ b/jvm/core/src/main/java/ml/dmlc/tvm/rpc/Server.java
@@ -17,31 +17,12 @@
 
 package ml.dmlc.tvm.rpc;
 
-import sun.misc.SharedSecrets;
-
-import java.io.FileDescriptor;
-import java.io.FileInputStream;
 import java.io.IOException;
-import java.io.InputStream;
-import java.net.Socket;
 
 /**
  * RPC Server.
  */
 public class Server {
-  private static SocketFileDescriptorGetter defaultSocketFdGetter
-      = new SocketFileDescriptorGetter() {
-          @Override public int get(Socket socket) {
-            try {
-              InputStream is = socket.getInputStream();
-              FileDescriptor fd = ((FileInputStream) is).getFD();
-              return SharedSecrets.getJavaIOFileDescriptorAccess().get(fd);
-            } catch (IOException e) {
-              e.printStackTrace();
-              return -1;
-            }
-          }
-        };
   private final WorkerThread worker;
 
   private static class WorkerThread extends Thread {
@@ -72,35 +53,10 @@ public void terminate() {
   /**
    * Start a standalone server.
    * @param serverPort Port.
-   * @param socketFdGetter Method to get system file descriptor of the server socket.
-   * @throws IOException if failed to bind localhost:port.
-   */
-  public Server(int serverPort, SocketFileDescriptorGetter socketFdGetter) throws IOException {
-    worker = new WorkerThread(new StandaloneServerProcessor(serverPort, socketFdGetter));
-  }
-
-  /**
-   * Start a standalone server.
-   * Use sun.misc.SharedSecrets.getJavaIOFileDescriptorAccess
-   * to get file descriptor for the socket.
-   * @param serverPort Port.
    * @throws IOException if failed to bind localhost:port.
    */
   public Server(int serverPort) throws IOException {
-    this(serverPort, defaultSocketFdGetter);
-  }
-
-  /**
-   * Start a server connected to proxy.
-   * @param proxyHost The proxy server host.
-   * @param proxyPort The proxy server port.
-   * @param key The key to identify the server.
-   * @param socketFdGetter Method to get system file descriptor of the server socket.
-   */
-  public Server(String proxyHost, int proxyPort, String key,
-      SocketFileDescriptorGetter socketFdGetter) {
-    worker = new WorkerThread(
-      new ConnectProxyServerProcessor(proxyHost, proxyPort, key, socketFdGetter));
+    worker = new WorkerThread(new StandaloneServerProcessor(serverPort));
   }
 
   /**
@@ -112,7 +68,8 @@ public Server(String proxyHost, int proxyPort, String key,
    * @param key The key to identify the server.
    */
   public Server(String proxyHost, int proxyPort, String key) {
-    this(proxyHost, proxyPort, key, defaultSocketFdGetter);
+    worker = new WorkerThread(
+        new ConnectProxyServerProcessor(proxyHost, proxyPort, key));
   }
 
   /**
diff --git a/jvm/core/src/main/java/ml/dmlc/tvm/rpc/SocketChannel.java b/jvm/core/src/main/java/ml/dmlc/tvm/rpc/SocketChannel.java
new file mode 100644
index 000000000000..e72581b2358f
--- /dev/null
+++ b/jvm/core/src/main/java/ml/dmlc/tvm/rpc/SocketChannel.java
@@ -0,0 +1,49 @@
+package ml.dmlc.tvm.rpc;
+
+import ml.dmlc.tvm.Function;
+import ml.dmlc.tvm.TVMValue;
+import ml.dmlc.tvm.TVMValueBytes;
+
+import java.io.IOException;
+import java.net.Socket;
+
+public class SocketChannel {
+  private final Socket socket;
+
+  SocketChannel(Socket sock) {
+    socket = sock;
+  }
+
+  private Function fsend = Function.convertFunc(new Function.Callback() {
+    @Override public Object invoke(TVMValue... args) {
+      byte[] data = args[0].asBytes();
+      try {
+        socket.getOutputStream().write(data);
+      } catch (IOException e) {
+        e.printStackTrace();
+        return -1;
+      }
+      return data.length;
+    }
+  });
+
+  private Function frecv = Function.convertFunc(new Function.Callback() {
+    @Override public Object invoke(TVMValue... args) {
+      long size = args[0].asLong();
+      try {
+        return new TVMValueBytes(Utils.recvAll(socket.getInputStream(), (int) size));
+      } catch (IOException e) {
+        e.printStackTrace();
+        return -1;
+      }
+    }
+  });
+
+  public Function getFsend() {
+    return fsend;
+  }
+
+  public Function getFrecv() {
+    return frecv;
+  }
+}
diff --git a/jvm/core/src/main/java/ml/dmlc/tvm/rpc/SocketFileDescriptorGetter.java b/jvm/core/src/main/java/ml/dmlc/tvm/rpc/SocketFileDescriptorGetter.java
deleted file mode 100644
index 4c35f720009d..000000000000
--- a/jvm/core/src/main/java/ml/dmlc/tvm/rpc/SocketFileDescriptorGetter.java
+++ /dev/null
@@ -1,32 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You 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 ml.dmlc.tvm.rpc;
-
-import java.net.Socket;
-
-/**
- * Interface for defining different socket fd getter.
- */
-public interface SocketFileDescriptorGetter {
-  /**
-   * Get native socket file descriptor.
-   * @param socket Java socket.
-   * @return native socket fd.
-   */
-  public int get(Socket socket);
-}
diff --git a/jvm/core/src/main/java/ml/dmlc/tvm/rpc/StandaloneServerProcessor.java b/jvm/core/src/main/java/ml/dmlc/tvm/rpc/StandaloneServerProcessor.java
index 06e3303d1523..2d2303d3fe8a 100644
--- a/jvm/core/src/main/java/ml/dmlc/tvm/rpc/StandaloneServerProcessor.java
+++ b/jvm/core/src/main/java/ml/dmlc/tvm/rpc/StandaloneServerProcessor.java
@@ -28,12 +28,9 @@
  */
 public class StandaloneServerProcessor implements ServerProcessor {
   private final ServerSocket server;
-  private final SocketFileDescriptorGetter socketFileDescriptorGetter;
 
-  public StandaloneServerProcessor(int serverPort,
-      SocketFileDescriptorGetter sockFdGetter) throws IOException {
+  public StandaloneServerProcessor(int serverPort) throws IOException {
     this.server = new ServerSocket(serverPort);
-    this.socketFileDescriptorGetter = sockFdGetter;
   }
 
   @Override public void terminate() {
@@ -46,9 +43,9 @@ public StandaloneServerProcessor(int serverPort,
 
   @Override public void run() {
     try {
-      Socket socket = server.accept();
-      InputStream in = socket.getInputStream();
-      OutputStream out = socket.getOutputStream();
+      final Socket socket = server.accept();
+      final InputStream in = socket.getInputStream();
+      final OutputStream out = socket.getOutputStream();
       int magic = Utils.wrapBytes(Utils.recvAll(in, 4)).getInt();
       if (magic != RPC.RPC_MAGIC) {
         Utils.closeQuietly(socket);
@@ -66,12 +63,10 @@ public StandaloneServerProcessor(int serverPort,
         out.write(Utils.toBytes(serverKey));
       }
 
+      SocketChannel sockChannel = new SocketChannel(socket);
       System.err.println("Connection from " + socket.getRemoteSocketAddress().toString());
-      final int sockFd = socketFileDescriptorGetter.get(socket);
-      if (sockFd != -1) {
-        new NativeServerLoop(sockFd).run();
-        System.err.println("Finish serving " + socket.getRemoteSocketAddress().toString());
-      }
+      new NativeServerLoop(sockChannel.getFsend(), sockChannel.getFrecv()).run();
+      System.err.println("Finish serving " + socket.getRemoteSocketAddress().toString());
       Utils.closeQuietly(socket);
     } catch (Throwable e) {
       e.printStackTrace();
diff --git a/jvm/core/src/test/java/ml/dmlc/tvm/contrib/GraphRuntimeTest.java b/jvm/core/src/test/java/ml/dmlc/tvm/contrib/GraphRuntimeTest.java
index d719eb6f61e7..a29402867381 100644
--- a/jvm/core/src/test/java/ml/dmlc/tvm/contrib/GraphRuntimeTest.java
+++ b/jvm/core/src/test/java/ml/dmlc/tvm/contrib/GraphRuntimeTest.java
@@ -17,7 +17,10 @@
 
 package ml.dmlc.tvm.contrib;
 
-import ml.dmlc.tvm.*;
+import ml.dmlc.tvm.Module;
+import ml.dmlc.tvm.NDArray;
+import ml.dmlc.tvm.TVMContext;
+import ml.dmlc.tvm.TestUtils;
 import ml.dmlc.tvm.rpc.Client;
 import ml.dmlc.tvm.rpc.RPCSession;
 import ml.dmlc.tvm.rpc.Server;
diff --git a/jvm/pom.xml b/jvm/pom.xml
index 99cfe0d7b5ec..150c3a00a894 100644
--- a/jvm/pom.xml
+++ b/jvm/pom.xml
@@ -164,8 +164,8 @@
         <artifactId>maven-compiler-plugin</artifactId>
         <version>3.3</version>
         <configuration>
-          <source>1.6</source>
-          <target>1.6</target>
+          <source>1.7</source>
+          <target>1.7</target>
           <encoding>UTF-8</encoding>
         </configuration>
       </plugin>
diff --git a/python/tvm/rpc/tracker.py b/python/tvm/rpc/tracker.py
index f31625cd34ed..b9b29a7fe4a1 100644
--- a/python/tvm/rpc/tracker.py
+++ b/python/tvm/rpc/tracker.py
@@ -230,7 +230,7 @@ def call_handler(self, args):
             port, matchkey = args[2]
             self.pending_matchkeys.add(matchkey)
             # got custom address (from rpc server)
-            if args[3] is not None:
+            if len(args) >= 4 and args[3] is not None:
                 value = (self, args[3], port, matchkey)
             else:
                 value = (self, self._addr[0], port, matchkey)
diff --git a/src/common/socket.h b/src/common/socket.h
index 2a2d9166a134..39bcff863c10 100644
--- a/src/common/socket.h
+++ b/src/common/socket.h
@@ -27,8 +27,10 @@
 #define TVM_COMMON_SOCKET_H_
 
 #if defined(_WIN32)
+#define NOMINMAX
 #include <winsock2.h>
 #include <ws2tcpip.h>
+#undef NOMINMAX
 using ssize_t = int;
 #ifdef _MSC_VER
 #pragma comment(lib, "Ws2_32.lib")
diff --git a/src/runtime/rpc/rpc_event_impl.cc b/src/runtime/rpc/rpc_event_impl.cc
index 7a142f3373db..3f4782693d8a 100644
--- a/src/runtime/rpc/rpc_event_impl.cc
+++ b/src/runtime/rpc/rpc_event_impl.cc
@@ -29,32 +29,14 @@
 namespace tvm {
 namespace runtime {
 
-class CallbackChannel final : public RPCChannel {
- public:
-  explicit CallbackChannel(PackedFunc fsend)
-      : fsend_(fsend) {}
-
-  size_t Send(const void* data, size_t size) final {
-    TVMByteArray bytes;
-    bytes.data = static_cast<const char*>(data);
-    bytes.size = size;
-    uint64_t ret = fsend_(bytes);
-    return static_cast<size_t>(ret);
-  }
-
-  size_t Recv(void* data, size_t size) final {
-    LOG(FATAL) << "Do not allow explicit receive for";
-    return 0;
-  }
-
- private:
-  PackedFunc fsend_;
-};
-
 PackedFunc CreateEventDrivenServer(PackedFunc fsend,
                                    std::string name,
                                    std::string remote_key) {
-  std::unique_ptr<CallbackChannel> ch(new CallbackChannel(fsend));
+  static PackedFunc frecv([](TVMArgs args, TVMRetValue* rv) {
+    LOG(FATAL) << "Do not allow explicit receive";
+    return 0;
+  });
+  std::unique_ptr<CallbackChannel> ch(new CallbackChannel(fsend, frecv));
   std::shared_ptr<RPCSession> sess =
       RPCSession::Create(std::move(ch), name, remote_key);
   return PackedFunc([sess](TVMArgs args, TVMRetValue* rv) {
diff --git a/src/runtime/rpc/rpc_session.cc b/src/runtime/rpc/rpc_session.cc
index f235ec8e8f0c..39db150bd3a0 100644
--- a/src/runtime/rpc/rpc_session.cc
+++ b/src/runtime/rpc/rpc_session.cc
@@ -36,6 +36,7 @@
 #include <algorithm>
 #include "rpc_session.h"
 #include "../../common/ring_buffer.h"
+#include "../../common/socket.h"
 
 namespace tvm {
 namespace runtime {
@@ -1260,5 +1261,26 @@ PackedFunc WrapTimeEvaluator(PackedFunc pf,
   return PackedFunc(ftimer);
 }
 
+size_t CallbackChannel::Send(const void* data, size_t size) {
+  TVMByteArray bytes;
+  bytes.data = static_cast<const char*>(data);
+  bytes.size = size;
+  int64_t n = fsend_(bytes);
+  if (n == -1) {
+    common::Socket::Error("CallbackChannel::Send");
+  }
+  return static_cast<size_t>(n);
+}
+
+size_t CallbackChannel::Recv(void* data, size_t size) {
+  TVMRetValue ret = frecv_(size);
+  if (ret.type_code() != kBytes) {
+    common::Socket::Error("CallbackChannel::Recv");
+  }
+  std::string* bytes = ret.ptr<std::string>();
+  memcpy(static_cast<char*>(data), bytes->c_str(), bytes->length());
+  return bytes->length();
+}
+
 }  // namespace runtime
 }  // namespace tvm
diff --git a/src/runtime/rpc/rpc_session.h b/src/runtime/rpc/rpc_session.h
index bc0bc8fe5918..d982f68bcb6e 100644
--- a/src/runtime/rpc/rpc_session.h
+++ b/src/runtime/rpc/rpc_session.h
@@ -87,7 +87,7 @@ class RPCChannel {
    */
   virtual size_t Send(const void* data, size_t size) = 0;
   /*!
-e   * \brief Recv data from channel.
+   * \brief Recv data from channel.
    *
    * \param data The data pointer.
    * \param size The size fo the data.
@@ -253,6 +253,37 @@ class RPCSession {
   std::string remote_key_;
 };
 
+/*!
+ * \brief RPC channel which callback
+ * frontend (Python/Java/etc.)'s send & recv function
+ */
+class CallbackChannel final : public RPCChannel {
+ public:
+  explicit CallbackChannel(PackedFunc fsend, PackedFunc frecv)
+      : fsend_(std::move(fsend)), frecv_(std::move(frecv)) {}
+
+  ~CallbackChannel() {}
+  /*!
+   * \brief Send data over to the channel.
+   * \param data The data pointer.
+   * \param size The size fo the data.
+   * \return The actual bytes sent.
+   */
+  size_t Send(const void* data, size_t size) final;
+  /*!
+   * \brief Recv data from channel.
+   *
+   * \param data The data pointer.
+   * \param size The size fo the data.
+   * \return The actual bytes received.
+   */
+  size_t Recv(void* data, size_t size) final;
+
+ private:
+  PackedFunc fsend_;
+  PackedFunc frecv_;
+};
+
 /*!
  * \brief Wrap a timer function to measure the time cost of a given packed function.
  * \param f The function argument.
diff --git a/src/runtime/rpc/rpc_socket_impl.cc b/src/runtime/rpc/rpc_socket_impl.cc
index 16528bcc68a1..65d37531159f 100644
--- a/src/runtime/rpc/rpc_socket_impl.cc
+++ b/src/runtime/rpc/rpc_socket_impl.cc
@@ -36,7 +36,7 @@ class SockChannel final : public RPCChannel {
       : sock_(sock) {}
   ~SockChannel() {
     if (!sock_.BadSocket()) {
-        sock_.Close();
+      sock_.Close();
     }
   }
   size_t Send(const void* data, size_t size) final {
@@ -109,12 +109,25 @@ void RPCServerLoop(int sockfd) {
       "SockServerLoop", "")->ServerLoop();
 }
 
+void RPCServerLoop(PackedFunc fsend, PackedFunc frecv) {
+  RPCSession::Create(std::unique_ptr<CallbackChannel>(
+      new CallbackChannel(fsend, frecv)),
+      "SockServerLoop", "")->ServerLoop();
+}
+
 TVM_REGISTER_GLOBAL("rpc._Connect")
 .set_body_typed(RPCClientConnect);
 
 TVM_REGISTER_GLOBAL("rpc._ServerLoop")
 .set_body([](TVMArgs args, TVMRetValue* rv) {
-    RPCServerLoop(args[0]);
+    if (args.size() == 1) {
+      RPCServerLoop(args[0]);
+    } else {
+      CHECK_EQ(args.size(), 2);
+      RPCServerLoop(
+          args[0].operator tvm::runtime::PackedFunc(),
+          args[1].operator tvm::runtime::PackedFunc());
+    }
   });
 }  // namespace runtime
 }  // namespace tvm