diff --git a/scripts/base/frameworks/openflow/main.bro b/scripts/base/frameworks/openflow/main.bro
index 3f17b65753..198374a3bb 100644
--- a/scripts/base/frameworks/openflow/main.bro
+++ b/scripts/base/frameworks/openflow/main.bro
@@ -159,10 +159,10 @@ export {
 		## this should never change, but there are not
 		## constants available in records
 		## defaults to OFPAT_OUTPUT
-		_type: ofp_action_type &default=OFPAT_OUTPUT;
+		type_: ofp_action_type &default=OFPAT_OUTPUT;
 		#_len: count &default=8;
 		## Output port.
-		_port: count &default=OFPP_FLOOD;
+		port_: count &default=OFPP_FLOOD;
 		#_max_len: count &optional;
 	};
 
@@ -239,95 +239,94 @@ export {
 		actions: vector of ofp_action_output;
 	};
 
-	## Function to modify flows in a openflow flow table.
-	##
-	## dpid: The openflow controller datapath id.
-	##
-	## flow_mod: The openflow flow_mod record which describes
-	##           the flow to delete, modify or add.
-	##
-	## Returns: T, if successful, else F.
-	global flow_mod: function(dpid: count, flow_mod: ofp_flow_mod): bool
-			&default=function(dpid: count, flow_mod: ofp_flow_mod): bool
-		{
-		Reporter::warning("Openflow::flow_mod function not implemented. Please load the right Openflow plugin");
-		return F;
-		};
-
-	## Function to get flow stats from the openflow switch/router
-	##
-	## dpid: The openflow controller datapath id.
-	##
-	## Returns: list with the installed flows and their statistics
-	global flow_stats: function(dpid: count): vector of ofp_flow_stats
-			&default=function(dpid: count): vector of ofp_flow_stats
-		{
-		Reporter::warning("Openflow::flow_stats function not implemented. Please load the right Openflow plugin");
-		return vector();
-		};
-
-	## Function to get the unique id out of a given cookie
-	##
-	## cookie: The openflow match cookie
-	##
-	## Returns: The cookie unique id
-	global get_cookie_uid: function(cookie: count): count;
-
-	## Function to get the group id out of a given cookie
+	## Function to get the unique id out of a given cookie.
 	##
 	## cookie: The openflow match cookie.
 	##
-	## Returns: The cookie group id
+	## Returns: The cookie unique id.
+	global get_cookie_uid: function(cookie: count): count;
+
+	## Function to get the group id out of a given cookie.
+	##
+	## cookie: The openflow match cookie.
+	##
+	## Returns: The cookie group id.
 	global get_cookie_gid: function(cookie: count): count;
 
+	## Function to get the group id out of a given cookie.
+	##
+	## cookie: The openflow match cookie.
+	##
+	## Returns: The cookie group id.
+	global generate_cookie: function(cookie: count &default=0): count;
+
 	## Event to signal that a flow has been successfully modified.
 	##
 	## flow_mod: The openflow flow_mod record which describes
 	##           the flow to delete, modify or add.
 	##
 	## msg: Message to describe the event.
-	global Openflow::flow_mod_success: event(flow_mod: ofp_flow_mod, msg: string &default = "Flow successfully modified");
+	global Openflow::flow_mod_success: event(flow_mod: ofp_flow_mod, msg: string &default="Flow successfully modified");
 
 	## Event to signal that a flow mod has failed.
 	##
 	## flow_mod: The openflow flow_mod record which describes
-	##           the flow to delete, modify ord add.
+	##           the flow to delete, modify or add.
 	##
 	## msg: Message to describe the event.
-	global Openflow::flow_mod_failure: event(flow_mod: ofp_flow_mod, msg: string &default = "Could not modify flow");
+	global Openflow::flow_mod_failure: event(flow_mod: ofp_flow_mod, msg: string &default="Could not modify flow");
+
+	## Available openflow plugins
+	type Plugin: enum {
+		PLACEHOLDER,
+	};
+
+	## Controller related state.
+	## Can be redefined by plugins to
+	## add state.
+	type ControllerState: record {
+		## Controller ip.
+		ip: addr &optional;
+		## Controller listen port.
+		port_: count &optional;
+		## Openflow switch datapath id.
+		dpid: count &optional;
+		## Type of the openflow plugin.
+		type_: Plugin;
+	} &redef;
+
+	## Controller record representing an openflow controller
+	type Controller: record {
+		## Controller related state.
+		state: ControllerState;
+		## flow_mod function the plugin implements
+		flow_mod: function(state: ControllerState, flow_mod: ofp_flow_mod): bool;
+		## flow_stats function the plugin implements if existing 
+		flow_stats: function(state: ControllerState): vector of ofp_flow_stats &optional;
+	};
+
+	## Global flow_mod function wrapper
+	##
+	## controller: The controller which should execute the flow modification
+	##
+	## flow_mod: The openflow flow_mod record which describes
+	##           the flow to delete, modify or add
+	##
+	## Returns: T if successfull, else F
+	global flow_mod: function(controller: Controller, flow_mod: ofp_flow_mod): bool;
 }
 
-
-# Flow Modification function prototype
-type FlowModFunc: function(dpid: count, flow_mod: ofp_flow_mod): bool;
-
-
-# Flow Statistics function prototype
-type FlowStatsFunc: function(dpid: count): vector of ofp_flow_stats;
-
-
-# Hook for registering openflow plugins
-global register_openflow_plugin: hook();
-
-
-# Function for plugins to call when they register their flow_mod function.
-function register_openflow_mod_func(func: FlowModFunc)
+# the flow_mod function wrapper
+function flow_mod(controller: Controller, flow_mod: ofp_flow_mod): bool
 	{
-	flow_mod = func;
-	}
-
-
-# Function for plugins to call when they register their flow_stats function.
-function register_openflow_stats_func(func: FlowStatsFunc)
-	{
-	flow_stats = func;
+		return controller$flow_mod(controller$state, flow_mod);
 	}
 
 
 # local function to forge a flow_mod cookie for this framework.
 # all flow entries from the openflow framework should have the
 # 42 bit of the cookie set.
-function generate_cookie(cookie: count &default = 0): count
+function generate_cookie(cookie: count &default=0): count
 	{
 	local c = BRO_COOKIE_ID * COOKIE_BID_START;
 	if(cookie >= COOKIE_UID_SIZE)
@@ -366,10 +365,3 @@ function get_cookie_gid(cookie: count): count
 		);
 	return INVALID_COOKIE;
 	}
-
-
-event bro_init()
-	{
-	# Call all of the plugin registration hooks
-	hook register_openflow_plugin();
-	}
diff --git a/scripts/base/frameworks/openflow/plugins/ryu.bro b/scripts/base/frameworks/openflow/plugins/ryu.bro
index a3360c3098..156168782e 100644
--- a/scripts/base/frameworks/openflow/plugins/ryu.bro
+++ b/scripts/base/frameworks/openflow/plugins/ryu.bro
@@ -4,19 +4,16 @@
 @load base/utils/active-http
 
 
-module Openflow;
+module OpenflowRyu;
 
 
 export {
-	## The Ryu openflow controller IP.
-	const controller_ip = "0.0.0.0" &redef;
-	## The port where the ReST API listens on.
-	const controller_port = "8080" &redef;
+	redef enum Openflow::Plugin += {
+		Openflow::RYU,
+	};
 
 	## Ryu error definitions.
-	type RyuError: enum {
-		## The controller IP needs to be redefined.
-		CONTROLLER_IP_REDEF,
+	type Error: enum {
 		## The openflow command type is not available
 		## for this ryu openflow plugin.
 		COMMAND_TYPE_NOT_AVAILABLE,
@@ -33,7 +30,18 @@ export {
 	## error: The error why the plugin aborted.
 	##
 	## msg: More detailed error description.
-	global Openflow::ryu_error: event(flow_mod: ofp_flow_mod, error: RyuError, msg: string &default="");
+	global OpenflowRyu::error: event(flow_mod: Openflow::ofp_flow_mod, error: Error, msg: string &default="");
+
+	## Ryu controller constructor.
+	##
+	## ip: Controller ip.
+	##
+	## port_: Controller listen port.
+	##
+	## dpid: Openflow switch datapath id.
+	##
+	## Returns: Openflow::Controller record
+	global new: function(ip: addr, port_: count, dpid: count): Openflow::Controller;
 }
 
 
@@ -62,7 +70,7 @@ type ryu_flow_action_output: record {
 # https://media.readthedocs.org/pdf/ryu/latest/ryu.pdf
 # on page 278-299 (30.10.2014)
 # Ryu ReST API flow_mod type.
-type ryu_flow_mod: record {
+type ryu_ofp_flow_mod: record {
 	dpid: count;
 	cookie: count &optional;
 	cookie_mask: count &optional;
@@ -77,82 +85,73 @@ type ryu_flow_mod: record {
 };
 
 
-# Hook to register the Ryu openflow plugin's flow_mod function
-# as the one the openflow framework should use.
-hook register_openflow_plugin()
+# Ryu flow_mod function
+function flow_mod(state: Openflow::ControllerState, flow_mod: Openflow::ofp_flow_mod): bool
 	{
-	register_openflow_mod_func(
-		function(dpid: count, flow_mod: ofp_flow_mod): bool
+	# Generate ryu_flow_actions because their type differs (using strings as type).
+	local _flow_actions: vector of ryu_flow_action_output;
+	for(i in flow_mod$actions)
+		{
+		switch(flow_mod$actions[i]$type_)
 			{
-			# Check if the controller_ip has been redefined.
-			if(controller_ip == "0.0.0.0")
-				{
-				Reporter::warning("The constant Openflow::controller_ip must be redefined");
-				event Openflow::ryu_error(flow_mod, CONTROLLER_IP_REDEF, cat(controller_ip));
+			case Openflow::OFPAT_OUTPUT:
+				_flow_actions[|_flow_actions|] = ryu_flow_action_output($_port=flow_mod$actions[i]$port_);
+				break;
+			default:
+				Reporter::warning(fmt("The given Openflow action type '%s' is not available", flow_mod$actions[i]$type_));
+				event OpenflowRyu::error(flow_mod, ACTION_TYPE_NOT_AVAILABLE, cat(flow_mod$actions[i]$type_));
 				return F;
-				}
-			# Generate ryu_flow_actions because their type differs (using strings as type).
-			local _flow_actions: vector of ryu_flow_action_output;
-			for(i in flow_mod$actions)
-				{
-				switch(flow_mod$actions[i]$_type)
-					{
-					case OFPAT_OUTPUT:
-						_flow_actions[|_flow_actions|] = ryu_flow_action_output($_port=flow_mod$actions[i]$_port);
-						break;
-					default:
-						Reporter::warning(fmt("The given Openflow action type '%s' is not available", flow_mod$actions[i]$_type));
-						event Openflow::ryu_error(flow_mod, ACTION_TYPE_NOT_AVAILABLE, cat(flow_mod$actions[i]$_type));
-						return F;
-					}
-				}
-			# Generate our ryu_flow_mod record for the ReST API call.
-			local _flow_mod: ryu_flow_mod = ryu_flow_mod(
-				$dpid=dpid,
-				$cookie=generate_cookie(flow_mod$cookie),
-				$idle_timeout=flow_mod$idle_timeout,
-				$hard_timeout=flow_mod$hard_timeout,
-				$match=flow_mod$match,
-				$actions=_flow_actions
-			);
-			# Type of the command
-			local command_type: string;
-			switch(flow_mod$command)
-				{
-				case OFPFC_ADD:
-					command_type = "add";
-					break;
-				case OFPFC_DELETE:
-					command_type = "delete";
-					break;
-				default:
-					Reporter::warning(fmt("The given Openflow command type '%s' is not available", cat(flow_mod$command)));
-					event Openflow::ryu_error(flow_mod, COMMAND_TYPE_NOT_AVAILABLE, cat(flow_mod$command));
-					return F;
-				}
-			# Create the ActiveHTTP request and convert the record to a Ryu ReST API JSON string
-			local request: ActiveHTTP::Request = ActiveHTTP::Request(
-				$url=cat("http://", controller_ip, ":", controller_port, RYU_FLOWENTRY_PATH, command_type),
-				$method="POST",
-				$client_data=JSON::convert(_flow_mod)
-			);
-			# Execute call to Ryu's ReST API
-			when(local result = ActiveHTTP::request(request))
-				{
-				if(result$code == 200)
-					event Openflow::flow_mod_success(flow_mod, result$body);
-				else
-					{
-					Reporter::warning(fmt("Flow modification failed with error: %s", result$body));
-					event Openflow::flow_mod_failure(flow_mod, result$body);
-					return F;
-					}
-				}
-
-			return T;
 			}
+		}
+	# Generate our ryu_flow_mod record for the ReST API call.
+	local _flow_mod: ryu_ofp_flow_mod = ryu_ofp_flow_mod(
+		$dpid=state$dpid,
+		$cookie=Openflow::generate_cookie(flow_mod$cookie),
+		$idle_timeout=flow_mod$idle_timeout,
+		$hard_timeout=flow_mod$hard_timeout,
+		$match=flow_mod$match,
+		$actions=_flow_actions
 	);
+	# Type of the command
+	local command_type: string;
+	switch(flow_mod$command)
+		{
+		case Openflow::OFPFC_ADD:
+			command_type = "add";
+			break;
+		case Openflow::OFPFC_DELETE:
+			command_type = "delete";
+			break;
+		default:
+			Reporter::warning(fmt("The given Openflow command type '%s' is not available", cat(flow_mod$command)));
+			event OpenflowRyu::error(flow_mod, COMMAND_TYPE_NOT_AVAILABLE, cat(flow_mod$command));
+			return F;
+		}
+	# Create the ActiveHTTP request and convert the record to a Ryu ReST API JSON string
+	local request: ActiveHTTP::Request = ActiveHTTP::Request(
+		$url=cat("http://", cat(state$ip), ":", cat(state$port_), RYU_FLOWENTRY_PATH, command_type),
+		$method="POST",
+		$client_data=OpenflowJSON::convert(_flow_mod)
+	);
+	# Execute call to Ryu's ReST API
+	when(local result = ActiveHTTP::request(request))
+		{
+		if(result$code == 200)
+			event Openflow::flow_mod_success(flow_mod, result$body);
+		else
+			{
+			Reporter::warning(fmt("Flow modification failed with error: %s", result$body));
+			event Openflow::flow_mod_failure(flow_mod, result$body);
+			return F;
+			}
+		}
 
-	# TODO: implement when a JSON -> record converter exists
-	# register_openflow_stats_func();
+	return T;
 	}
+
+
+# Ryu controller constructor
+function new(ip: addr, port_: count, dpid: count): Openflow::Controller
+	{
+	return [$state=[$ip=ip, $port_=port_, $type_=Openflow::RYU, $dpid=dpid], $flow_mod=flow_mod];
+	}
\ No newline at end of file
diff --git a/scripts/base/frameworks/openflow/utils/json.bro b/scripts/base/frameworks/openflow/utils/json.bro
index 7ec77fdb60..b29619afc3 100644
--- a/scripts/base/frameworks/openflow/utils/json.bro
+++ b/scripts/base/frameworks/openflow/utils/json.bro
@@ -1,6 +1,6 @@
 @load base/utils/strings
 
-module JSON;
+module OpenflowJSON;
 
 export {
 	## A function to convert arbitrary Bro data into a JSON string.
@@ -72,7 +72,7 @@ function convert(v: any, only_loggable: bool &default=F, field_escape_pattern: p
 				field = cat(sub(field, field_escape_pattern, ""));
 			if ( field_desc?$value && (!only_loggable || field_desc$log) )
 				{
-				local onepart = cat("\"", field, "\": ", JSON::convert(field_desc$value, only_loggable));
+				local onepart = cat("\"", field, "\": ", OpenflowJSON::convert(field_desc$value, only_loggable));
 				rec_parts[|rec_parts|] = onepart;
 				}
 			}
@@ -86,7 +86,7 @@ function convert(v: any, only_loggable: bool &default=F, field_escape_pattern: p
 		local sa: set[bool] = v;
 		for ( sv in sa ) 
 			{
-			set_parts[|set_parts|] = JSON::convert(sv, only_loggable);
+			set_parts[|set_parts|] = OpenflowJSON::convert(sv, only_loggable);
 			}
 		return cat("[", join_string_vec(set_parts, ", "), "]");
 		}
@@ -96,9 +96,9 @@ function convert(v: any, only_loggable: bool &default=F, field_escape_pattern: p
 		local ta: table[bool] of any = v;
 		for ( ti in ta ) 
 			{
-			local ts = JSON::convert(ti);
+			local ts = OpenflowJSON::convert(ti);
 			local if_quotes = (ts[0] == "\"") ? "" : "\"";
-			tab_parts[|tab_parts|] = cat(if_quotes, ts, if_quotes, ": ", JSON::convert(ta[ti], only_loggable));
+			tab_parts[|tab_parts|] = cat(if_quotes, ts, if_quotes, ": ", OpenflowJSON::convert(ta[ti], only_loggable));
 			}
 		return cat("{", join_string_vec(tab_parts, ", "), "}");
 		}
@@ -108,7 +108,7 @@ function convert(v: any, only_loggable: bool &default=F, field_escape_pattern: p
 		local va: vector of any = v;
 		for ( vi in va )
 			{
-			vec_parts[|vec_parts|] = JSON::convert(va[vi], only_loggable);
+			vec_parts[|vec_parts|] = OpenflowJSON::convert(va[vi], only_loggable);
 			}
 		return cat("[", join_string_vec(vec_parts, ", "), "]");
 		}
diff --git a/scripts/site/openflow-shunt.bro b/scripts/site/openflow-shunt.bro
index 0a46b14a4d..193f80e4f2 100644
--- a/scripts/site/openflow-shunt.bro
+++ b/scripts/site/openflow-shunt.bro
@@ -2,8 +2,10 @@
 @load base/frameworks/notice
 @load base/frameworks/openflow
 
+
 module OpenflowShunt;
 
+
 # pox
 # global param_dpid = "00-24-a8-5c-0c-00|15" &redef;
 # global param_port = "\"OFPP_ALL\"" &redef;
@@ -12,7 +14,6 @@ module OpenflowShunt;
 
 
 # default constants which are not automatically gathered.
-redef Openflow::controller_ip = "10.255.0.20";
 const dpid = 4222282094087168;
 const cookie = 0;
 const idle_timeout = 30;
@@ -38,6 +39,7 @@ export {
 
 function size_callback(c: connection, cnt: count): interval
 	{
+	local controller = OpenflowRyu::new(10.255.0.20, 8080, dpid);
 	# print Openflow::flow_stats(dpid);
 	# if traffic exceeds the given threshold, remove flow.
 	if ( c$orig$num_bytes_ip + c$resp$num_bytes_ip >= size_threshold )
@@ -45,8 +47,8 @@ function size_callback(c: connection, cnt: count): interval
 		# create openflow flow_mod add records from connection data and give default constants
 		local actions: vector of Openflow::ofp_action_output;
 		local reverse_actions: vector of Openflow::ofp_action_output;
-		actions[|actions|] = Openflow::ofp_action_output($_port=out_port);
-		reverse_actions[|reverse_actions|] = Openflow::ofp_action_output($_port=in_port);
+		actions[|actions|] = Openflow::ofp_action_output($port_=out_port);
+		reverse_actions[|reverse_actions|] = Openflow::ofp_action_output($port_=in_port);
 		# flow layer 4 protocol
 		local nw_proto = Openflow::IP_TCP;
 		if(is_udp_port(c$id$orig_p))
@@ -93,9 +95,8 @@ function size_callback(c: connection, cnt: count): interval
 		];
 
 		# call openflow framework
-		if(Openflow::flow_mod(dpid, flow_mod) && Openflow::flow_mod(dpid, reverse_flow_mod)) {
+		if(Openflow::flow_mod(controller, flow_mod) && Openflow::flow_mod(controller, reverse_flow_mod))
 			event shunt_triggered(c);
-		}
 
 		if(delete_flow)
 			{
@@ -132,7 +133,7 @@ event Openflow::flow_mod_failure(flow_mod: Openflow::ofp_flow_mod, msg: string)
 	}
 
 
-event Openflow::ryu_error(flow_mod: Openflow::ofp_flow_mod, error: Openflow::RyuError, msg: string)
+event OpenflowRyu::error(flow_mod: Openflow::ofp_flow_mod, error: OpenflowRyu::Error, msg: string)
 	{
 	print fmt("ERROR: %s, msg: %s\n%s", error, msg, flow_mod);
 	}