Index: ulp/ipoib_NDIS6_CM/kernel/ipoib_port.cpp
===================================================================
--- ulp/ipoib_NDIS6_CM/kernel/ipoib_port.cpp	(revision 3007)
+++ ulp/ipoib_NDIS6_CM/kernel/ipoib_port.cpp	(working copy)
@@ -7399,6 +7399,7 @@
 {
 	ib_api_status_t		status;
 	ib_mcast_req_t		mcast_req;
+	ib_ca_attr_t * 		p_ca_attrs;
 
 	IPOIB_ENTER( IPOIB_DBG_INIT );
 
@@ -7423,8 +7424,21 @@
 	cl_memclr( &mcast_req, sizeof(mcast_req) );
 	/* Copy the results of the Get to use as parameters. */
 	mcast_req.member_rec = *p_member_rec;
+	
 	/* We specify our port GID for the join operation. */
-	mcast_req.member_rec.port_gid.unicast.prefix = IB_DEFAULT_SUBNET_PREFIX;
+	status =__port_query_ca_attrs( p_port, &p_ca_attrs);
+	if ( status == IB_SUCCESS ) 
+	{
+		mcast_req.member_rec.port_gid.unicast.prefix = 
+			p_ca_attrs->p_port_attr->p_gid_table[0].unicast.prefix;
+		cl_free ( p_ca_attrs );
+	}
+	else 
+	{	
+		ASSERT ( status != IB_SUCCESS );
+		mcast_req.member_rec.port_gid.unicast.prefix = IB_DEFAULT_SUBNET_PREFIX;
+	}
+	
 	mcast_req.member_rec.port_gid.unicast.interface_id =
 		p_port->p_adapter->guids.port_guid.guid;