diff --git a/Makefile b/Makefile
index a26d3ce..9e9453d 100644
--- a/Makefile
+++ b/Makefile
@@ -32,6 +32,8 @@
 DOCKER_LABEL_COMMIT_DATE ?= $(shell git diff-index --quiet HEAD -- && git show -s --format=%cd --date=iso-strict HEAD || echo "unknown" )
 DOCKER_LABEL_BUILD_DATE  ?= $(shell date -u "+%Y-%m-%dT%H:%M:%SZ")
 
+
+# Targets
 all: test
 
 docker-build:
diff --git a/package.json b/package.json
index fe064f5..d2bff8d 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
     "name": "cord_workflow_controller",
-    "version": "0.2.0",
+    "version": "0.3.0",
     "description": "CORD Workflow Controller",
     "main": "src/server.js",
     "scripts": {
@@ -24,7 +24,6 @@
       "async": "^3.1.0",
       "node-yaml-config": "0.0.5",
       "socket.io": "^2.2.0",
-      "socketio-wildcard": "^2.0.0",
       "double-ended-queue": "^2.1.0-0",
       "test": "^0.6.0",
       "winston": "^3.2.1",
diff --git a/spec/eventrouter.spec.js b/spec/eventrouter.spec.js
index 0b2a217..82261f7 100644
--- a/spec/eventrouter.spec.js
+++ b/spec/eventrouter.spec.js
@@ -168,7 +168,7 @@
 
             // remove workflow runs
             _.forOwn(workflowRunInfos, (workflowRunInfo) => {
-                workflowManagerClients[0].emit(server.serviceEvents.WORKFLOW_REMOVE_RUN, {
+                workflowManagerClients[0].emit(eventrouter.serviceEvents.WORKFLOW_REMOVE_RUN, {
                     workflow_id: workflowRunInfo.workflowId,
                     workflow_run_id: workflowRunInfo.workflowRunId
                 });
@@ -177,7 +177,7 @@
 
             // remove workflows
             _.forOwn(workflowIds, (workflowId) => {
-                workflowManagerClients[0].emit(server.serviceEvents.WORKFLOW_REMOVE, {
+                workflowManagerClients[0].emit(eventrouter.serviceEvents.WORKFLOW_REMOVE, {
                     workflow_id: workflowId
                 });
             });
@@ -231,7 +231,10 @@
             this.timeout(5000);
 
             // kickstart the workflow
-            probeClient.emit('onu.events', {serialNumber: 'testSerialXXX', other: 'test_other_field'});
+            probeClient.emit(eventrouter.serviceEvents.EVENT_EMIT, {
+                topic: 'onu.events',
+                message: {serialNumber: 'testSerialXXX', other: 'test_other_field'}
+            });
             setTimeout(() => {
                 expect(receivedKickstartMessages.length, 'num of message stores').to.equal(2);
                 receivedKickstartMessages.forEach((receivedKickstartMessageStore) => {
@@ -245,7 +248,10 @@
             this.timeout(5000);
 
             // kickstart the workflow
-            probeClient.emit('onu.events', {serialNumber: 'testSerialXXX', other: 'test_other_field'});
+            probeClient.emit(eventrouter.serviceEvents.EVENT_EMIT, {
+                topic: 'onu.events',
+                message: {serialNumber: 'testSerialXXX', other: 'test_other_field'}
+            });
             setTimeout(() => {
                 // kickstart will take 2 seconds roughly
                 expect(workflowRunInfos.length, 'num of workflow runs').to.equal(1);
@@ -259,7 +265,10 @@
             this.timeout(5000);
 
             // kickstart the workflow
-            probeClient.emit('onu.events', {serialNumber: 'testSerialXXX', other: 'test_other_field'});
+            probeClient.emit(eventrouter.serviceEvents.EVENT_EMIT, {
+                topic: 'onu.events',
+                message: {serialNumber: 'testSerialXXX', other: 'test_other_field'}
+            });
             setTimeout(() => {
                 // kickstart will take 2 seconds roughly
                 expect(workflowRunInfos.length, 'num of workflow runs').to.equal(1);
@@ -297,14 +306,14 @@
             this.timeout(5000);
 
             // kickstart the workflow
-            probeClient.emit(
-                'onu.events',
-                {serialNumber: 'testSerialXXX', other: 'test_other_field'}
-            );
-            probeClient.emit(
-                'datamodel.AttWorkflowDriverServiceInstance',
-                {operation: 'update', serialNumber: 'testSerialXXX', other: 'updated_test_other_field'}
-            );
+            probeClient.emit(eventrouter.serviceEvents.EVENT_EMIT, {
+                topic: 'onu.events',
+                message: {serialNumber: 'testSerialXXX', other: 'test_other_field'}
+            });
+            probeClient.emit(eventrouter.serviceEvents.EVENT_EMIT, {
+                topic: 'datamodel.AttWorkflowDriverServiceInstance',
+                message: {operation: 'update', serialNumber: 'testSerialXXX', other: 'updated_test_other_field'}
+            });
             setTimeout(() => {
                 // kickstart will take 2 seconds roughly
                 expect(workflowRunInfos.length, 'num of workflow runs').to.equal(1);
diff --git a/spec/websocket_clients.spec.js b/spec/websocket_clients.spec.js
index b1f6333..b9401bc 100644
--- a/spec/websocket_clients.spec.js
+++ b/spec/websocket_clients.spec.js
@@ -146,7 +146,10 @@
                 },
                 (callback) => {
                     // kickstart the test workflow
-                    probeClient.emit('onu.events', {serialNumber: 'testSerialXXX', other: 'test_other_field'});
+                    probeClient.emit(eventrouter.serviceEvents.EVENT_EMIT, {
+                        topic: 'onu.events',
+                        message: {serialNumber: 'testSerialXXX', other: 'test_other_field'}
+                    });
                     setTimeout(() => {
                         expect(workflowRunId).to.not.be.undefined;
                         callback(null, true);
diff --git a/src/controllers/eventrouter.js b/src/controllers/eventrouter.js
index 4919669..cc7d222 100644
--- a/src/controllers/eventrouter.js
+++ b/src/controllers/eventrouter.js
@@ -22,6 +22,7 @@
     const logger = require('../config/logger.js');
     const Client = require('../types/client.js');
     const WorkflowRun = require('../types/workflowrun.js');
+    const ws_probe = require('./ws_probe.js');
     const ws_manager = require('./ws_manager.js');
     const ws_workflowrun = require('./ws_workflowrun.js');
 
@@ -44,12 +45,17 @@
         GREETING: 'cord.workflow.ctlsvc.greeting'
     };
 
-    // add ws_mgroperation events
+    // add ws_probe events
+    _.forOwn(ws_probe.serviceEvents, (wsServiceEvent, key) => {
+        serviceEvents[key] = wsServiceEvent;
+    });
+
+    // add ws_manager events
     _.forOwn(ws_manager.serviceEvents, (wsServiceEvent, key) => {
         serviceEvents[key] = wsServiceEvent;
     });
 
-    // add ws_runoperation events
+    // add ws_workflowrun events
     _.forOwn(ws_workflowrun.serviceEvents, (wsServiceEvent, key) => {
         serviceEvents[key] = wsServiceEvent;
     });
@@ -250,7 +256,7 @@
         return true;
     };
 
-    const sendEvent = (topic, message) => {
+    const emitEvent = (topic, message) => {
         // list of workflowIds
         // to check if there are workflow runs for the events
         let workflowIdsRunning = [];
@@ -359,41 +365,62 @@
         }
 
         if(c.getType() === Client.Type.PROBE) {
-            // probe' messages are relayed
-            // relay messages based on topic
+            // probe
             // probe protocol:
             // REQ:
-            //      topic: event topic
-            //      message: <data>
+            //      topic: operation
+            //      message: {
+            //          req_id: <req_id>,
+            //          topic: <topic>,
+            //          message: <data>
+            //      }
             // RES:
             //      topic: topic sent
-            //      message: {result: <true/false>, message: <error message> }
+            //      message: {
+            //          req_id: <req_id>,
+            //          error: <true/false>,
+            //          result: <true/false>,
+            //          message: <error message>
+            //      }
             allClients[clientId] = c;
             probeClients[clientId] = c;
 
-            socket.on('*', (msg) => {
-                let jsonMsg = msg.data;
-                if(jsonMsg.length === 2) {
-                    // must have two parts
-                    // first part is topic
-                    // second part is message body
-                    let topic = jsonMsg[0];
-                    let messageBody = jsonMsg[1];
+            // attach probe operations
+            let router = ws_probe.getRouter();
+            _.forOwn(router, (routerElem, _key) => {
+                socket.on(routerElem.topic, (msg) => {
+                    // handle a common parameter - req_id
+                    // when we get req_id, return the same req_id in response.
+                    // this is to help identify a request from a response at client-side
+                    let req_id = 101010; // default number, signiture
+                    if(msg && checkObject(msg)) {
+                        if('req_id' in msg) {
+                            req_id = msg.req_id;
+                        }
+                    }
 
-                    sendEvent(topic, messageBody);
+                    routerElem.handler(routerElem.topic, msg || {}, (err, result) => {
+                        if(err) {
+                            logger.log('warn', `unable to handle a message - ${err}`);
+                            socket.emit(routerElem.topic, {
+                                req_id: req_id,
+                                error: true,
+                                result: result,
+                                message: err
+                            });
+                            return;
+                        }
 
-                    // return true for success
-                    socket.emit(topic, {
-                        result: true
+                        // we return result
+                        if(routerElem.return === undefined || routerElem.return) {
+                            socket.emit(routerElem.topic, {
+                                req_id: req_id,
+                                error: false,
+                                result: result
+                            });
+                        }
                     });
-                }
-                else {
-                    logger.log('warn', `unexpected message is received - ${JSON.stringify(jsonMsg)}`);
-                    socket.emit(jsonMsg[0], {
-                        result: false,
-                        message: `unexpected message is received - ${JSON.stringify(jsonMsg)}`
-                    });
-                }
+                });
             });
             return true;
         }
@@ -601,7 +628,7 @@
         getWorkflowRunClients: () => { return workflowRunClients; },
         clientType: Client.Type,
         //setIO: setIO,
-        sendEvent: sendEvent,
+        emitEvent: emitEvent,
         countQueuedEvents: countQueuedEvents,
         fetchEvent: fetchEvent,
         addClient: addClient,
diff --git a/src/controllers/websocket.js b/src/controllers/websocket.js
index b5eaf13..6112449 100644
--- a/src/controllers/websocket.js
+++ b/src/controllers/websocket.js
@@ -18,7 +18,6 @@
     'use strict';
 
     const socketio = require('socket.io');
-    const ioWildcard = require('socketio-wildcard');
     const client = require('../types/client.js');
     const eventrouter = require('./eventrouter.js');
     const logger = require('../config/logger.js');
@@ -30,7 +29,6 @@
             pingInterval: 500,
             pingTimeout: 2000,
         });
-        io.use(ioWildcard());
 
         // set io to eventrouter
         //eventrouter.setIO(io);
diff --git a/src/controllers/ws_probe.js b/src/controllers/ws_probe.js
new file mode 100644
index 0000000..a897086
--- /dev/null
+++ b/src/controllers/ws_probe.js
@@ -0,0 +1,93 @@
+/*
+ * Copyright 2019-present Open Networking Foundation
+
+ * 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.
+ */
+
+
+(function () {
+    'use strict';
+
+    const logger = require('../config/logger.js');
+
+    let serviceEvents = {
+        // probe -> controller -> probe
+        EVENT_EMIT: 'cord.workflow.ctlsvc.event.emit'
+    };
+
+    // WebSocket interface for emitting an event
+    // Message format:
+    // {
+    //     topic: 'cord.workflow.ctlsvc.event.emit',
+    //     message: {
+    //         req_id: <req_id>, // optional
+    //         topic: <topic>,
+    //         message: <message>
+    //     }
+    // }
+    const emitEvent = (topic, message, cb) => {
+        const eventrouter = require('./eventrouter.js');
+
+        let errorMessage;
+        if(!message) {
+            // error
+            errorMessage = `Message body for topic ${topic} is null or empty`;
+            logger.log('warn', `Return error - ${errorMessage}`);
+            cb(errorMessage, false);
+            return;
+        }
+
+        if(!('topic' in message)) {
+            // error
+            errorMessage = `field 'topic' does not exist in message body - ${JSON.stringify(message)}`;
+            logger.log('warn', `Return error - ${errorMessage}`);
+            cb(errorMessage, false);
+            return;
+        }
+
+        if(!('message' in message)) {
+            // error
+            errorMessage = `field 'message' does not exist in message body - ${JSON.stringify(message)}`;
+            logger.log('warn', `Return error - ${errorMessage}`);
+            cb(errorMessage, false);
+            return;
+        }
+
+        let result = eventrouter.emitEvent(
+            message.topic,
+            message.message
+        );
+        if(!result) {
+            errorMessage = `failed to emit event ${message.topic} - ${message.message}`;
+            cb(errorMessage, false);
+        }
+        else {
+            cb(null, true);
+        }
+        return;
+    };
+
+    const getRouter = () => {
+        return {
+            emitEvent: {
+                topic: serviceEvents.EVENT_EMIT,
+                handler: emitEvent
+            }
+        };
+    };
+
+    module.exports = {
+        serviceEvents: serviceEvents,
+        getRouter: getRouter
+    };
+})();