diff --git a/src/ServiceDiscovery/Services.cpp b/src/ServiceDiscovery/Services.cpp
index 47a96f9..78ae7f4 100644
--- a/src/ServiceDiscovery/Services.cpp
+++ b/src/ServiceDiscovery/Services.cpp
@@ -73,7 +73,7 @@ bool Services::SendAlarm(const std::string& message, unsigned int level, const s
              + ",\"severity\":0"
              + ",\"message\":\"" + message + "\"}";
   
-  ok = ok && m_backend_client.SendMulticast(cmd_string, &err);
+  ok = ok && m_backend_client.SendMulticast(MulticastType::Log,cmd_string, &err);
   
   if(!ok){
     std::clog<<"SendAlarm (log) error: "<<err<<std::endl;
@@ -546,7 +546,7 @@ bool Services::SendLog(const std::string& message, unsigned int severity, const
   
   std::string err="";
   
-  if(!m_backend_client.SendMulticast(cmd_string, &err)){
+  if(!m_backend_client.SendMulticast(MulticastType::Log,cmd_string, &err)){
     std::clog<<"SendLog error: "<<err<<std::endl;
     return false;
   }
@@ -556,13 +556,14 @@ bool Services::SendLog(const std::string& message, unsigned int severity, const
 }
 
 
-bool Services::SendMonitoringData(const std::string& json_data, const std::string& device, unsigned int timestamp){
+bool Services::SendMonitoringData(const std::string& json_data, const std::string& subject, const std::string& device, unsigned int timestamp){
   
   const std::string& name = (device=="") ? m_name : device;
   
   std::string cmd_string = std::string{"{ \"topic\":\"monitoring\""}
                          + ", \"time\":"+std::to_string(timestamp)
                          + ", \"device\":\""+ name +"\""
+                         + ", \"subject\":\""+ subject +"\""
                          + ", \"data\":\""+ json_data +"\" }";
   
   if(cmd_string.length()>655355){
@@ -572,7 +573,7 @@ bool Services::SendMonitoringData(const std::string& json_data, const std::strin
   
   std::string err="";
   
-  if(!m_backend_client.SendMulticast(cmd_string, &err)){
+  if(!m_backend_client.SendMulticast(MulticastType::Monitoring,cmd_string, &err)){
     std::clog<<"SendMonitoringData error: "<<err<<std::endl;
     return false;
   }
@@ -640,7 +641,7 @@ bool Services::SendTemporaryROOTplot(const std::string& plot_name, const std::st
   
   std::string err="";
   
-  if(!m_backend_client.SendMulticast(cmd_string, &err)){
+  if(!m_backend_client.SendMulticast(MulticastType::Log,cmd_string, &err)){
     std::clog<<"SendROOTplot error: "<<err<<std::endl;
     return false;
   }
diff --git a/src/ServiceDiscovery/Services.h b/src/ServiceDiscovery/Services.h
index 97d466e..fb40902 100644
--- a/src/ServiceDiscovery/Services.h
+++ b/src/ServiceDiscovery/Services.h
@@ -35,7 +35,7 @@ namespace ToolFramework {
     
     bool SendLog(const std::string& message, unsigned int severity=2, const std::string& device="", const unsigned int timestamp=0);
     bool SendAlarm(const std::string& message, unsigned int level=0, const std::string& device="", const unsigned int timestamp=0, const unsigned int timeout=SERVICES_DEFAULT_TIMEOUT);
-    bool SendMonitoringData(const std::string& json_data, const std::string& device="", unsigned int timestamp=0);
+    bool SendMonitoringData(const std::string& json_data, const std::string& subject, const std::string& device="", unsigned int timestamp=0);
     bool SendCalibrationData(const std::string& json_data, const std::string& description, const std::string& device="", unsigned int timestamp=0, int* version=nullptr, const unsigned int timeout=SERVICES_DEFAULT_TIMEOUT);
     bool GetCalibrationData(std::string& json_data, int version=-1, const std::string& device="", const unsigned int timeout=SERVICES_DEFAULT_TIMEOUT);
     bool SendDeviceConfig(const std::string& json_data, const std::string& author, const std::string& description, const std::string& device="", unsigned int timestamp=0, int* version=nullptr, const unsigned int timeout=SERVICES_DEFAULT_TIMEOUT);
diff --git a/src/ServiceDiscovery/ServicesBackend.cpp b/src/ServiceDiscovery/ServicesBackend.cpp
index 2f80b55..a6b712c 100644
--- a/src/ServiceDiscovery/ServicesBackend.cpp
+++ b/src/ServiceDiscovery/ServicesBackend.cpp
@@ -270,16 +270,18 @@ bool ServicesBackend::InitMulticast(){
 	/*              Multicast Setup              */
 	/* ----------------------------------------- */
 	
-	int multicast_port = 55554;
-	std::string multicast_address = "239.192.1.1"; // FIXME suitable default?
+	int log_port = 55554;
+	int mon_port = 55553;
+	std::string multicast_address = "239.192.1.1";
 	
-	// FIXME add to config file
-	m_variables.Get("multicast_port",multicast_port);
+	m_variables.Get("log_port",log_port);
+	m_variables.Get("mon_port",mon_port);
 	m_variables.Get("multicast_address",multicast_address);
 	
 	// set up multicast socket for sending logging & monitoring data
-	multicast_socket = socket(AF_INET, SOCK_DGRAM, 0);
-	if(multicast_socket<=0){
+	log_socket = socket(AF_INET, SOCK_DGRAM, 0);
+	mon_socket = socket(AF_INET, SOCK_DGRAM, 0);
+	if(log_socket<=0 || mon_socket<=0){
 		Log(std::string{"Failed to open multicast socket with error "}+strerror(errno),v_error,verbosity);
 		return false;
 	}
@@ -288,14 +290,16 @@ bool ServicesBackend::InitMulticast(){
 	struct linger l;
 	l.l_onoff  = 0;  // whether to linger
 	l.l_linger = 0;  // seconds to linger for
-	get_ok = setsockopt(multicast_socket, SOL_SOCKET, SO_LINGER,(char*) &l, sizeof(l));
+	get_ok =           setsockopt(log_socket, SOL_SOCKET, SO_LINGER,(char*) &l, sizeof(l));
+	get_ok = get_ok || setsockopt(mon_socket, SOL_SOCKET, SO_LINGER,(char*) &l, sizeof(l));
 	if(get_ok!=0){
 		Log(std::string{"Failed to set multicast socket linger with error "}+strerror(errno),v_error,verbosity);
 		return false;
 	}
 	
 	// set the socket to non-blocking mode - seems like a good idea...? XXX
-	get_ok = fcntl(multicast_socket, F_SETFL, O_NONBLOCK);
+	get_ok =           fcntl(log_socket, F_SETFL, O_NONBLOCK);
+	get_ok = get_ok || fcntl(mon_socket, F_SETFL, O_NONBLOCK);
 	if(get_ok!=0){
 		Log(std::string{"Failed to set multicast socket to non-blocking with error "}
 		   +strerror(errno),v_error,verbosity);
@@ -303,19 +307,22 @@ bool ServicesBackend::InitMulticast(){
 	}
 	
 	// format destination address from IP string
-	bzero((char *)&multicast_addr, sizeof(multicast_addr)); // init to 0
-	multicast_addr.sin_family = AF_INET;
-	multicast_addr.sin_port = htons(multicast_port);
+	bzero((char *)&log_addr, sizeof(log_addr)); // init to 0
+	log_addr.sin_family = AF_INET;
+	log_addr.sin_port = htons(log_port);
+	mon_addr = log_addr;
+	mon_addr.sin_port = htons(mon_port);
 	// convert destination address string to binary
-	get_ok = inet_aton(multicast_address.c_str(), &multicast_addr.sin_addr);
-	if(get_ok==0){
+	get_ok =           inet_aton(multicast_address.c_str(), &log_addr.sin_addr);
+	get_ok = get_ok && inet_aton(multicast_address.c_str(), &mon_addr.sin_addr);
+	if(get_ok==0){ // returns 0 on failure, not success
 		Log("Bad multicast address '"+multicast_address+"'",v_error,verbosity);
 		return false;
 	}
-	multicast_addrlen = sizeof(multicast_addr);
+	multicast_addrlen = sizeof(log_addr);
 	
 	// apparently we can poll with zmq?
-	multicast_poller = zmq::pollitem_t{ NULL, multicast_socket, ZMQ_POLLOUT, 0 };
+	//multicast_poller = zmq::pollitem_t{ NULL, multicast_socket, ZMQ_POLLOUT, 0 };
 	
 	return true;
 }
@@ -364,17 +371,22 @@ bool ServicesBackend::BackgroundThread(std::future<void> signaller){
 	return true;
 }
 
-bool ServicesBackend::SendMulticast(std::string command, std::string* err){
+bool ServicesBackend::SendMulticast(MulticastType type, std::string command, std::string* err){
 	// multicast send. These do not wait for a response, so no timeout.
 	// only immediately evident errors are reported. receipt is not confirmed.
 	if(verbosity>10) std::cout<<"ServicesBackend::SendMulticast invoked with command '"<<command<<"'"<<std::endl;
+	// type: 0=logging, 1=monitoring
+	int multicast_socket = (type==MulticastType::Log) ? log_socket : mon_socket;
+	struct sockaddr_in* multicast_addr = (type==MulticastType::Log) ? &log_addr : &mon_addr; 
 	
-	// check for listeners...?
-	zmq::poll(&multicast_poller,1, 0);   // timeout 0 = return immediately... XXX
+	/*
+	// check for listeners...? - seems redundant, multicast can always send
+	zmq::poll(&multicast_poller,1, 0);   // timeout 0 = return immediately...
 	if(multicast_poller.revents & ZMQ_POLLOUT){
+	*/
 		
 		// got a listener - ship it
-		int cnt = sendto(multicast_socket, command.c_str(), command.length()+1, 0, (struct sockaddr*)&multicast_addr, multicast_addrlen);
+		int cnt = sendto(multicast_socket, command.c_str(), command.length()+1, 0, (struct sockaddr*)multicast_addr, multicast_addrlen);
 		if(cnt < 0){
 			std::string errmsg = "Error sending multicast message: "+std::string{strerror(errno)};
 			Log(errmsg,v_error,verbosity);
@@ -382,7 +394,7 @@ bool ServicesBackend::SendMulticast(std::string command, std::string* err){
 			return false;
 		}
 		
-	}
+	//}
 	
 	return true;
 }
@@ -770,7 +782,8 @@ bool ServicesBackend::Finalise(){
 	if(utilities) utilities->RemoveService("slowcontrol_read");
 	
 	Log("ServicesBackend Closing multicast socket",v_debug,verbosity);
-	close(multicast_socket);
+	close(log_socket);
+	close(mon_socket);
 	
 	Log("ServicesBackend Deleting Utilities class",v_debug,verbosity);
 	if(utilities){
diff --git a/src/ServiceDiscovery/ServicesBackend.h b/src/ServiceDiscovery/ServicesBackend.h
index a776dc9..7b7c791 100644
--- a/src/ServiceDiscovery/ServicesBackend.h
+++ b/src/ServiceDiscovery/ServicesBackend.h
@@ -46,6 +46,8 @@ struct Command {
 
 enum class SlowControlMsg { Query, Log, Alarm, Monitoring, Calibration, Config };
 
+enum class MulticastType { Log, Monitoring };
+
 class ServicesBackend {
 	public:
 	ServicesBackend(){};
@@ -60,7 +62,7 @@ class ServicesBackend {
 	bool SendCommand(const std::string& topic, const std::string& command, std::string* results=nullptr, const unsigned int* timeout_ms=nullptr, std::string* err=nullptr);
 	
 	// multicasts
-	bool SendMulticast(std::string command, std::string* err=nullptr);
+	bool SendMulticast(MulticastType type, std::string command, std::string* err=nullptr);
 	
 	
 	private:
@@ -85,10 +87,12 @@ class ServicesBackend {
 	std::vector<zmq::pollitem_t> in_polls;
 	std::vector<zmq::pollitem_t> out_polls;
 	
-	// multicast socket file descriptor
-	int multicast_socket=-1;
+	// multicast socket file descriptors
+	int log_socket=-1;
+	int mon_socket=-1;
 	// multicast destination address structure
-	struct sockaddr_in multicast_addr;
+	struct sockaddr_in log_addr;
+	struct sockaddr_in mon_addr;
 	socklen_t multicast_addrlen;
 	// apparently works with zmq poller?
 	zmq::pollitem_t multicast_poller;