diff --git a/apps/t3/src/main/java/org/onosproject/t3/api/TroubleshootService.java b/apps/t3/src/main/java/org/onosproject/t3/api/TroubleshootService.java
index ab7ff29..5b19cc2 100644
--- a/apps/t3/src/main/java/org/onosproject/t3/api/TroubleshootService.java
+++ b/apps/t3/src/main/java/org/onosproject/t3/api/TroubleshootService.java
@@ -17,6 +17,7 @@
 package org.onosproject.t3.api;
 
 import org.onlab.packet.EthType;
+import org.onlab.packet.VlanId;
 import org.onosproject.net.ConnectPoint;
 import org.onosproject.net.HostId;
 import org.onosproject.net.flow.TrafficSelector;
@@ -48,6 +49,14 @@
     Generator<Set<StaticPacketTrace>> pingAllGenerator(EthType.EtherType type);
 
     /**
+     * Requests a static trace be performed for all mcast Routes in the network.
+     *
+     * @param vlanId the vlanId configured for multicast.
+     * @return a set of trace result yielded one by one.
+     */
+    Generator<Set<StaticPacketTrace>> traceMcast(VlanId vlanId);
+
+    /**
      * Requests a static trace be performed between the two hosts in the network, given a type of traffic.
      *
      * @param sourceHost      source host