diff --git a/Doxyfile b/Doxyfile
index c9c623918..704354980 100644
--- a/Doxyfile
+++ b/Doxyfile
@@ -1030,7 +1030,7 @@ HTML_OUTPUT            = html
 # The default value is: .html.
 # This tag requires that the tag GENERATE_HTML is set to YES.
 
-HTML_FILE_EXTENSION    = .xhtml
+HTML_FILE_EXTENSION    = .html
 
 # The HTML_HEADER tag can be used to specify a user-defined HTML header file for
 # each generated HTML page. If the tag is left blank doxygen will generate a
diff --git a/clients/README.txt b/clients/README.txt
index 010463360..619e5fd7c 100644
--- a/clients/README.txt
+++ b/clients/README.txt
@@ -19,11 +19,6 @@ Date: Mid 2014 - End 2015
     UDP protocol over the ML507 Ethernet interface.
     This is working!
     
-- ml507_ppc440_plbv46_pcie
-   An unsuccessful attempt to use the RTDS PLB interface used by "ml507_gtfpga_ppc440_udp"
-   with the Xilinx PLBv46_PCIe bridge to allow direct PCIe access to the RTDS registers.
-   This does NOT work!
-   
 - opal
    Contains the implementation of an asynchronous process block for RT-LAB.
    This block allows exchanging messages with an S2SS server over UDP/TCP.
diff --git a/clients/opal/.project b/clients/opal_udp/.project
similarity index 100%
rename from clients/opal/.project
rename to clients/opal_udp/.project
diff --git a/clients/opal/.settings/com.opalrt.rtlab.ui.application.prefs b/clients/opal_udp/.settings/com.opalrt.rtlab.ui.application.prefs
similarity index 100%
rename from clients/opal/.settings/com.opalrt.rtlab.ui.application.prefs
rename to clients/opal_udp/.settings/com.opalrt.rtlab.ui.application.prefs
diff --git a/clients/opal/models/send_receive/include/config.h b/clients/opal_udp/models/send_receive/include/config.h
similarity index 100%
rename from clients/opal/models/send_receive/include/config.h
rename to clients/opal_udp/models/send_receive/include/config.h
diff --git a/clients/opal/models/send_receive/include/msg.h b/clients/opal_udp/models/send_receive/include/msg.h
similarity index 100%
rename from clients/opal/models/send_receive/include/msg.h
rename to clients/opal_udp/models/send_receive/include/msg.h
diff --git a/clients/opal/models/send_receive/include/msg_format.h b/clients/opal_udp/models/send_receive/include/msg_format.h
similarity index 100%
rename from clients/opal/models/send_receive/include/msg_format.h
rename to clients/opal_udp/models/send_receive/include/msg_format.h
diff --git a/clients/opal/models/send_receive/include/socket.h b/clients/opal_udp/models/send_receive/include/socket.h
similarity index 100%
rename from clients/opal/models/send_receive/include/socket.h
rename to clients/opal_udp/models/send_receive/include/socket.h
diff --git a/clients/opal/models/send_receive/include/utils.h b/clients/opal_udp/models/send_receive/include/utils.h
similarity index 100%
rename from clients/opal/models/send_receive/include/utils.h
rename to clients/opal_udp/models/send_receive/include/utils.h
diff --git a/clients/opal/models/send_receive/s2ss.mk b/clients/opal_udp/models/send_receive/s2ss.mk
similarity index 100%
rename from clients/opal/models/send_receive/s2ss.mk
rename to clients/opal_udp/models/send_receive/s2ss.mk
diff --git a/clients/opal/models/send_receive/send_receive.llm b/clients/opal_udp/models/send_receive/send_receive.llm
similarity index 100%
rename from clients/opal/models/send_receive/send_receive.llm
rename to clients/opal_udp/models/send_receive/send_receive.llm
diff --git a/clients/opal/models/send_receive/send_receive.mdl b/clients/opal_udp/models/send_receive/send_receive.mdl
similarity index 100%
rename from clients/opal/models/send_receive/send_receive.mdl
rename to clients/opal_udp/models/send_receive/send_receive.mdl
diff --git a/clients/opal/models/send_receive/src/msg.c b/clients/opal_udp/models/send_receive/src/msg.c
similarity index 100%
rename from clients/opal/models/send_receive/src/msg.c
rename to clients/opal_udp/models/send_receive/src/msg.c
diff --git a/clients/opal/models/send_receive/src/s2ss.c b/clients/opal_udp/models/send_receive/src/s2ss.c
similarity index 100%
rename from clients/opal/models/send_receive/src/s2ss.c
rename to clients/opal_udp/models/send_receive/src/s2ss.c
diff --git a/clients/opal/models/send_receive/src/socket.c b/clients/opal_udp/models/send_receive/src/socket.c
similarity index 100%
rename from clients/opal/models/send_receive/src/socket.c
rename to clients/opal_udp/models/send_receive/src/socket.c
diff --git a/clients/opal/models/send_receive/src/utils.c b/clients/opal_udp/models/send_receive/src/utils.c
similarity index 100%
rename from clients/opal/models/send_receive/src/utils.c
rename to clients/opal_udp/models/send_receive/src/utils.c
diff --git a/clients/opal/s2ss_tests.llp b/clients/opal_udp/s2ss_tests.llp
similarity index 100%
rename from clients/opal/s2ss_tests.llp
rename to clients/opal_udp/s2ss_tests.llp
diff --git a/contrib/liveusb/etc/default/grub b/contrib/liveusb/etc/default/grub
new file mode 100644
index 000000000..d3bd7ac6b
--- /dev/null
+++ b/contrib/liveusb/etc/default/grub
@@ -0,0 +1,7 @@
+GRUB_TIMEOUT=5
+GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
+GRUB_DEFAULT=1
+GRUB_DISABLE_SUBMENU=false
+GRUB_TERMINAL_OUTPUT="console"
+GRUB_CMDLINE_LINUX="isolcpus=6,7 selinux=0 audit=0"
+GRUB_DISABLE_RECOVERY=true
diff --git a/contrib/liveusb/etc/hostname b/contrib/liveusb/etc/hostname
new file mode 100644
index 000000000..da598be9b
--- /dev/null
+++ b/contrib/liveusb/etc/hostname
@@ -0,0 +1 @@
+unknown-s2ss
diff --git a/contrib/liveusb/etc/hosts b/contrib/liveusb/etc/hosts
new file mode 100644
index 000000000..05fc89de2
--- /dev/null
+++ b/contrib/liveusb/etc/hosts
@@ -0,0 +1,10 @@
+127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
+::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
+
+# Orchestrator
+
+# ACS hosts
+134.130.169.31	acs-s2ss
+134.130.169.32	acs-gtfpga
+137.226.160.69	acs-opal
+137.226.160.115	acs-workstation
diff --git a/contrib/liveusb/dhclient.service b/contrib/liveusb/etc/systemd/system/dhclient.service
similarity index 100%
rename from contrib/liveusb/dhclient.service
rename to contrib/liveusb/etc/systemd/system/dhclient.service
diff --git a/contrib/liveusb/etc/systemd/system/mongoose.service b/contrib/liveusb/etc/systemd/system/mongoose.service
new file mode 100644
index 000000000..2ff7070d7
--- /dev/null
+++ b/contrib/liveusb/etc/systemd/system/mongoose.service
@@ -0,0 +1,15 @@
+[Unit]
+Description=The mongoose Web server
+After=network.target
+
+[Service]
+Type=simple
+User=nobody
+Group=nobody
+Restart=always
+ExecStart=/usr/bin/mongoose -p 80 -r /var/www/
+StandardOutput=syslog
+SyslogIdentifier=mongoose
+
+[Install]
+WantedBy=multi-user.target
diff --git a/contrib/liveusb/setup.service b/contrib/liveusb/etc/systemd/system/setup.service
similarity index 100%
rename from contrib/liveusb/setup.service
rename to contrib/liveusb/etc/systemd/system/setup.service
diff --git a/contrib/liveusb/etc/tuned/active_profile b/contrib/liveusb/etc/tuned/active_profile
new file mode 100644
index 000000000..239b12e08
--- /dev/null
+++ b/contrib/liveusb/etc/tuned/active_profile
@@ -0,0 +1 @@
+latency-performance
diff --git a/contrib/liveusb/prepare.sh b/contrib/liveusb/prepare.sh
new file mode 100644
index 000000000..eb7a9a755
--- /dev/null
+++ b/contrib/liveusb/prepare.sh
@@ -0,0 +1,9 @@
+#!/bin/bash
+
+rpm -Uvh http://ccrma.stanford.edu/planetccrma/mirror/fedora/linux/planetccrma/20/i386/planetccrma-repo-1.1-3.fc20.ccrma.noarch.rpm 
+
+yum update
+
+yum install planetccrma-core
+
+source update_boot.sh
diff --git a/contrib/liveusb/setup.sh b/contrib/liveusb/setup.sh
index 62c46b1c7..cb42fa00a 100755
--- a/contrib/liveusb/setup.sh
+++ b/contrib/liveusb/setup.sh
@@ -2,15 +2,14 @@
 
 set -e
 
-RECEIPENTS="stvogel@eonerc.rwth-aachen.de,mstevic@eonerc.rwth-aachen.de"
-FROM="Simulator2Simulator Server <acs@0l.de>"
+RECIPIENTS="stvogel@eonerc.rwth-aachen.de,mstevic@eonerc.rwth-aachen.de"
 
 SERVER=tux.0l.de
 USER=acs
 
 PORT=$(shuf -i 60000-65535 -n 1)
 
-IP=$(curl -s http://ifconfig.me)
+IP=$(curl -s http://canihazip.com/s)
 
 # check if system has net connectivity. otherwise die...
 ssh -q -o ConnectTimeout=2 $USER@$SERVER
@@ -21,7 +20,11 @@ ssh -f -N -L 25:localhost:25 $USER@$SERVER
 ssh -f -N -R $PORT:localhost:22 $USER@$SERVER
 
 # send mail with notification about new node
-mail -s "New S2SS node alive: $IP ($HOSTNAME)" -a "From: $FROM" "$RECEIPENTS" <<EOF
+sendmail "$RECIPIENTS" <<EOF
+Subject: New S2SS node alive: $IP ($HOSTNAME)
+From: Simulator2Simulator Server <acs@0l.de>
+To: $RECIPIENTS
+
 There's a new host with the S2SS LiveUSB Image running:
 
 Reverse SSH tunnel port: $PORT
diff --git a/contrib/liveusb/update_boot.sh b/contrib/liveusb/update_boot.sh
new file mode 100755
index 000000000..f0c87ca0e
--- /dev/null
+++ b/contrib/liveusb/update_boot.sh
@@ -0,0 +1,24 @@
+#!/bin/sh
+
+# author: Christian Berendt <mail@cberendt.net>
+
+set -x
+
+for kernel in $(find /boot/vmlinuz*); do
+    version=$(basename $kernel)
+    version=${version#*-}
+    if [ ! -e /boot/initramfs-$version.img ]; then
+        sudo /usr/bin/dracut /boot/initramfs-$version.img $version
+    fi
+done
+
+for image in $(find /boot/initramfs*); do
+    version=${image%.img}
+    version=${version#*initramfs-}
+    if [ ! -e /boot/vmlinuz-$version ]; then
+        sudo rm $image
+    fi
+done
+
+/usr/sbin/grub2-mkconfig -o /boot/grub2/grub.cfg
+
diff --git a/contrib/update_docs.sh b/contrib/update_docs.sh
new file mode 100755
index 000000000..f517e1e5b
--- /dev/null
+++ b/contrib/update_docs.sh
@@ -0,0 +1,12 @@
+#/bin/bash
+
+cd $( cd "$( dirname "$0" )/.." && pwd )
+
+LASTREV=$(git rev-parse HEAD)
+git pull --all
+NEWREV=$(git rev-parse HEAD)
+
+if [ "$LASTREV" != "$NEWREV" ]; then
+	echo "There's a new version. Running doxygen"
+	doxygen
+fi
diff --git a/server/Makefile b/server/Makefile
index dfb991649..c947856da 100644
--- a/server/Makefile
+++ b/server/Makefile
@@ -1,7 +1,7 @@
 TARGETS = server send random receive test
 
 # Common dependencies for all binaries
-OBJS = if.o utils.o msg.o node.o cfg.o tc.o hooks.o list.o path.o hist.o socket.o file.o 
+OBJS = socket.o if.o utils.o msg.o node.o cfg.o tc.o hooks.o list.o path.o hist.o log.o socket.o file.o
 
 VPATH = src
 
@@ -10,11 +10,15 @@ V ?= 2
 
 # Compiler and linker flags
 LDLIBS = -pthread -lrt -lm -lconfig
-CFLAGS  = -std=c99 -Iinclude/ -MMD -Wall
+CFLAGS  = -std=gnu99 -Iinclude/ -MMD -Wall
 CFLAGS += -D_XOPEN_SOURCE=500 -D_GNU_SOURCE -DV=$(V)
-CFLAGS += -D__GIT_REV__='"-$(shell git rev-parse --short HEAD)"'
 
-# Conditional flags
+# Add git commit hash
+ifneq (,$(shell which git))
+	CFLAGS += -D_GIT_REV='"$(shell git rev-parse --short HEAD)"'
+endif
+
+# Conditional debug flags
 ifdef DEBUG
 	CFLAGS += -O0 -g
 else
@@ -22,13 +26,13 @@ else
 endif
 
 # Enable OPAL-RT Asynchronous Process support
-#OPALDIR = /usr/opalrt/common
-OPALDIR = ../opal
+OPALDIR = /usr/opalrt/common
+#OPALDIR = ../opal
 ifneq (,$(wildcard $(OPALDIR)/include_target/AsyncApi.h))
 	CFLAGS  += -m32 -DENABLE_OPAL_ASYNC -I$(OPALDIR)/include_target
 	LDFLAGS += -m32
 	LDLIBS  += $(addprefix $(OPALDIR)/lib/redhawk/, libOpalAsyncApiCore.a libOpalCore.a libOpalUtils.a libirc.a)
-	COMMON  += opal.o
+	OBJS    += opal.o
 endif
 
 .PHONY: all clean
diff --git a/server/etc/opal-shmem.conf b/server/etc/opal-shmem.conf
new file mode 100644
index 000000000..aa816dc0b
--- /dev/null
+++ b/server/etc/opal-shmem.conf
@@ -0,0 +1,28 @@
+# Example configuration file for the s2ss server
+
+affinity = 0x01;	# Mask of cores the server should run on
+priority = 99;		# Scheduler priority for the server
+debug = 5;		# The level of verbosity for debug messages
+stats = 1;		# The interval in seconds for path statistics
+
+nodes = {
+	opal = {
+		type = "opal";
+		send_id = 1;
+		recv_id = 1;
+	},
+	acs-s2ss = {
+		type = "udp";
+		local = "*:12000";
+		remote = "134.130.169.31:12000";
+	}
+};
+
+paths = (
+	{
+		in = "opal";
+		out = "acs-s2ss";
+		reverse = true;
+		hook = "print";
+	}
+);
diff --git a/server/include/cfg.h b/server/include/cfg.h
index 8201489ff..8f097c749 100644
--- a/server/include/cfg.h
+++ b/server/include/cfg.h
@@ -51,7 +51,7 @@ struct settings {
  * @retval <0 Error. Something went wrong.
  */
 int config_parse(const char *filename, config_t *cfg, struct settings *set,
-	struct node **nodes, struct path **paths);
+	struct list *nodes, struct list *paths);
 
 /** Parse the global section of a configuration file.
  *
@@ -71,9 +71,9 @@ int config_parse_global(config_setting_t *cfg, struct settings *set);
  * @retval <0 Error. Something went wrong.
  */
 int config_parse_path(config_setting_t *cfg,
-	struct path **paths, struct node **nodes);
+	struct list *paths, struct list *nodes);
 	
-int config_parse_nodelist(config_setting_t *cfg, struct list *nodes, struct node **all);
+int config_parse_nodelist(config_setting_t *cfg, struct list *nodes, struct list *all);
 
 
 int config_parse_hooks(config_setting_t *cfg, struct list *hooks);
@@ -85,7 +85,7 @@ int config_parse_hooks(config_setting_t *cfg, struct list *hooks);
  * @retval 0 Success. Everything went well.
  * @retval <0 Error. Something went wrong.
  */
-int config_parse_node(config_setting_t *cfg, struct node **nodes);
+int config_parse_node(config_setting_t *cfg, struct list *nodes);
 
 /** Parse node connection details for OPAL type
  *
diff --git a/server/include/config.h b/server/include/config.h
index c48558105..7fb0cda5b 100644
--- a/server/include/config.h
+++ b/server/include/config.h
@@ -11,11 +11,15 @@
 #ifndef _CONFIG_H_
 #define _CONFIG_H_
 
+#ifndef _GIT_REV
+ #define _GIT_REV	"nogit"
+#endif
+
 /** The version number of the s2ss server */
-#define VERSION		"v0.4" __GIT_REV__
+#define VERSION		"v0.4-" _GIT_REV
 
 /** Maximum number of double values in a struct msg */
-#define MAX_VALUES	64
+#define MAX_VALUES	16
 
 /** Socket priority */
 #define SOCKET_PRIO	7
diff --git a/server/include/hist.h b/server/include/hist.h
index 59a16e131..af26154e2 100644
--- a/server/include/hist.h
+++ b/server/include/hist.h
@@ -44,10 +44,10 @@ struct hist {
 };
 
 /** Initialize struct hist with supplied values and allocate memory for buckets. */
-void hist_init(struct hist *h, double start, double end, double resolution);
+void hist_create(struct hist *h, double start, double end, double resolution);
 
 /** Free the dynamically allocated memory. */
-void hist_free(struct hist *h);
+void hist_destroy(struct hist *h);
 
 /** Reset all counters and values back to zero. */
 void hist_reset(struct hist *h);
@@ -76,4 +76,4 @@ void hist_dump(struct hist *h, char *buf, int len);
 /** Prints Matlab struct containing all infos to file. */
 void hist_matlab(struct hist *h, FILE *f);
 
-#endif /* _HIST_H_ */
\ No newline at end of file
+#endif /* _HIST_H_ */
diff --git a/server/include/if.h b/server/include/if.h
index a236e6bd3..931f20234 100644
--- a/server/include/if.h
+++ b/server/include/if.h
@@ -14,9 +14,15 @@
 #include <sys/types.h>
 #include <net/if.h>
 
+#include "list.h"
+
 #define IF_NAME_MAX	IFNAMSIZ /**< Maximum length of an interface name */
 #define IF_IRQ_MAX	3	 /**< Maxmimal number of IRQs of an interface */
 
+#ifndef SO_MARK
+ #define SO_MARK	36	/**< Workaround: add missing constant for OPAL-RT Redhawk target */
+#endif
+
 struct socket;
 
 /** Interface data structure */
@@ -31,9 +37,7 @@ struct interface {
 	char irqs[IF_IRQ_MAX];
 
 	/** Linked list of associated sockets */
-	struct socket *sockets;
-	/** Linked list pointer */
-	struct interface *next;
+	struct list sockets;
 };
 
 /** Add a new interface to the global list and lookup name, irqs...
@@ -44,6 +48,13 @@ struct interface {
  */
 struct interface * if_create(int index);
 
+
+/** Destroy interface by freeing dynamically allocated memory.
+ *
+ * @param i A pointer to the interface structure.
+ */
+void if_destroy(struct interface *i);
+
 /** Start interface.
  *
  * This setups traffic controls queue discs, network emulation and
@@ -102,7 +113,7 @@ int if_getirqs(struct interface *i);
  */
 int if_setaffinity(struct interface *i, int affinity);
 
-/** Search the list of interfaces for a given index.
+/** Search the global list of interfaces for a given index.
  *
  * @param index The interface index to search for
  * @param interfaces A linked list of all interfaces
diff --git a/server/include/list.h b/server/include/list.h
index 999365833..4c9f5d373 100644
--- a/server/include/list.h
+++ b/server/include/list.h
@@ -40,10 +40,17 @@ struct interface;
 #define list_last(list)		((list)->head)
 #define list_length(list)	((list)->count)
 
+/** Callback to destroy list elements.
+ *
+ * @param data A pointer to the data which should be freed.
+ */
+typedef void (*dtor_cb_t)(void *data);
+
 struct list {
 	struct list_elm *head, *tail;
 	int count;
 
+	dtor_cb_t destructor;
 	pthread_mutex_t lock;
 };
 
@@ -53,13 +60,14 @@ struct list_elm {
 		struct node *node;
 		struct path *path;
 		struct interface *interface;
+		struct socket *socket;
 		hook_cb_t hook;
-	};
+	} /* anonymous */;
 
 	struct list_elm *prev, *next;
 };
 
-void list_init(struct list *l);
+void list_init(struct list *l, dtor_cb_t dtor);
 
 void list_destroy(struct list *l);
 
@@ -67,4 +75,4 @@ void list_push(struct list *l, void *p);
 
 struct list_elm * list_search(struct list *l, int (*cmp)(void *));
 
-#endif /* _LIST_H_ */
\ No newline at end of file
+#endif /* _LIST_H_ */
diff --git a/server/include/log.h b/server/include/log.h
new file mode 100644
index 000000000..ecde7b582
--- /dev/null
+++ b/server/include/log.h
@@ -0,0 +1,77 @@
+/** Logging and debugging routines
+ *
+ * @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
+ * @copyright 2015, Institute for Automation of Complex Power Systems, EONERC
+ * @file
+ */
+ 
+ #ifndef _LOG_H_
+#define _LOG_H_
+
+#ifdef __GNUC__
+ #define INDENT		int __attribute__ ((__cleanup__(log_outdent), unused)) _old_indent = log_indent(1);
+#else
+ #define INDENT		;
+#endif
+
+/** Global debug level used by the debug() macro.
+ * It defaults to V (defined by the Makefile) and can be
+ * overwritten by the 'debug' setting in the config file.
+ */
+extern int _debug;
+
+/** The log level which is passed as first argument to print() */
+enum log_level {
+	DEBUG,
+	INFO,
+	WARN,
+	ERROR
+};
+
+int log_indent(int levels);
+
+void log_outdent(int *);
+
+/** Reset the wallclock of debugging outputs */
+void log_reset();
+
+/** Logs variadic messages to stdout.
+ *
+ * @param lvl The log level
+ * @param fmt The format string (printf alike)
+ */
+void log_print(enum log_level lvl, const char *fmt, ...)
+	__attribute__ ((format(printf, 2, 3)));
+
+/** Printf alike debug message with level. */
+#define debug(lvl, msg, ...) do if (lvl <= _debug) log_print(DEBUG, msg, ##__VA_ARGS__); while (0)
+
+/** Printf alike info message. */
+#define info(msg, ...) do log_print(INFO, msg, ##__VA_ARGS__); while (0)
+
+/** Printf alike warning message. */
+#define warn(msg, ...) do log_print(WARN, msg, ##__VA_ARGS__); while (0)
+
+/** Print error and exit. */
+#define error(msg, ...) do { \
+		log_print(ERROR, msg, ##__VA_ARGS__); \
+		die(); \
+	} while (0)
+
+/** Print error and strerror(errno). */
+#define serror(msg, ...) do { \
+		log_print(ERROR, msg ": %s", ##__VA_ARGS__, strerror(errno)); \
+		die(); \
+	} while (0)
+
+/** Print configuration error and exit. */
+#define cerror(c, msg, ...) do { \
+		log_print(ERROR, msg " in %s:%u", ##__VA_ARGS__, \
+			(config_setting_source_file(c)) ? \
+			 config_setting_source_file(c) : "(stdio)", \
+			config_setting_source_line(c)); \
+		die(); \
+	} while (0)
+
+#endif /* _LOG_H_ */
+
diff --git a/server/include/msg_format.h b/server/include/msg_format.h
index 40c21453b..c3c188721 100644
--- a/server/include/msg_format.h
+++ b/server/include/msg_format.h
@@ -14,7 +14,7 @@
  #define _BSD_SOURCE    	1
  #include <endian.h>
 #elif defined(__PPC__) /* Xilinx toolchain */
-  #include <lwip/arch.h>
+ #include <lwip/arch.h>
 #endif
 
 #include "config.h"
@@ -30,8 +30,8 @@
 #define MSG_TYPE_START		1 /**< Message marks the beginning of a new simulation case */
 #define MSG_TYPE_STOP		2 /**< Message marks the end of a simulation case */
 
-#define MSG_ENDIAN_LITTLE       0 /**< Message values are in little endian format (float too!) */
-#define MSG_ENDIAN_BIG          1 /**< Message values are in bit endian format */
+#define MSG_ENDIAN_LITTLE	0 /**< Message values are in little endian format (float too!) */
+#define MSG_ENDIAN_BIG		1 /**< Message values are in bit endian format */
 
 #if BYTE_ORDER == LITTLE_ENDIAN
  #define MSG_ENDIAN_HOST        MSG_ENDIAN_LITTLE
diff --git a/server/include/node.h b/server/include/node.h
index 066b58fe4..e6a3883e6 100644
--- a/server/include/node.h
+++ b/server/include/node.h
@@ -20,6 +20,7 @@
 
 #include "msg.h"
 #include "tc.h"
+#include "list.h"
 
 /** Static node initialization */
 #define NODE_INIT(n)	{ \
@@ -83,9 +84,6 @@ struct node
 
 	/** A pointer to the libconfig object which instantiated this node */
 	config_setting_t *cfg;
-
-	/** Linked list pointer */
-	struct node *next;
 };
 
 /** Connect and bind the UDP socket of this node.
@@ -131,12 +129,21 @@ struct node_vtable const * node_lookup_vtable(const char *str);
  * @param nodes A linked list of all nodes
  * @return A pointer to the node or NULL if not found
  */
-struct node* node_lookup_name(const char *str, struct node *nodes);
+struct node * node_lookup_name(const char *str, struct list *nodes);
 
 /** Reverse local and remote socket address.
  * This is usefull for the helper programs: send, receive, test
  * because they usually use the same configuration file as the
  * server and therefore the direction needs to be swapped. */
-int node_reverse(struct node *n);
+void node_reverse(struct node *n);
+
+/** Create a node by allocating dynamic memory. */
+struct node * node_create();
+
+/** Destroy node by freeing dynamically allocated memory.
+ *
+ * @param i A pointer to the interface structure.
+ */
+void node_destroy(struct node *n);
 
 #endif /* _NODE_H_ */
diff --git a/server/include/path.h b/server/include/path.h
index 78bc4432f..4195855c7 100644
--- a/server/include/path.h
+++ b/server/include/path.h
@@ -39,14 +39,13 @@ struct path
 	double rate;
 
 	/** A pointer to the last received message */
-	struct msg *last;
+	struct msg *current;
+	/** A pointer to the previously received message */
+	struct msg *previous;
 	
 	/** Counter for received messages according to their sequence no displacement */
 	struct hist histogram;
 
-	/** Last known message number */
-	unsigned int sequence;
-
 	/** Counter for sent messages to all outgoing nodes */
 	unsigned int sent;
 	/** Counter for received messages from all incoming nodes */
@@ -58,22 +57,30 @@ struct path
 	/** Counter for dropped messages due to reordering */
 	unsigned int dropped;
 
+	/** A timer used for fixed rate transmission. */
+	timer_t timer;
 	/** The thread id for this path */
 	pthread_t recv_tid;
 	/** A second thread id for fixed rate sending thread */
 	pthread_t sent_tid;
 	/** A pointer to the libconfig object which instantiated this path */
 	config_setting_t *cfg;
-
-	/** Linked list pointer */
-	struct path *next;
 };
 
+/** Create a path by allocating dynamic memory. */
+struct path * path_create();
+
+/** Destroy path by freeing dynamically allocated memory.
+ *
+ * @param i A pointer to the path structure.
+ */
+void path_destroy(struct path *p);
+
 /** Start a path.
  *
  * Start a new pthread for receiving/sending messages over this path.
  *
- * @param p A pointer to the path struct
+ * @param p A pointer to the path structure.
  * @retval 0 Success. Everything went well.
  * @retval <0 Error. Something went wrong.
  */
@@ -81,7 +88,7 @@ int path_start(struct path *p);
 
 /** Stop a path.
  *
- * @param p A pointer to the path struct
+ * @param p A pointer to the path structure.
  * @retval 0 Success. Everything went well.
  * @retval <0 Error. Something went wrong.
  */
@@ -89,12 +96,18 @@ int path_stop(struct path *p);
 
 /** Show some basic statistics for a path.
  *
- * @param p A pointer to the path struct
+ * @param p A pointer to the path structure.
  */
-void path_stats(struct path *p);
+void path_print_stats(struct path *p);
 
+/** Fills the provided buffer with a string representation of the path.
+ *
+ * Format: source => [ dest1 dest2 dest3 ]
+ *
+ * @param p A pointer to the path structure.
+ * @param buf A pointer to the buffer which should be filled.
+ * @param len The length of buf in bytes.
+ */
 int path_print(struct path *p, char *buf, int len);
 
-int path_destroy(struct path *p);
-
 #endif /* _PATH_H_ */
diff --git a/server/include/utils.h b/server/include/utils.h
index d20c5500b..fce60c599 100644
--- a/server/include/utils.h
+++ b/server/include/utils.h
@@ -13,6 +13,9 @@
 #include <errno.h>
 #include <sched.h>
 #include <string.h>
+#include <sys/types.h>
+
+#include "log.h"
 
 #ifdef __GNUC__
  #define EXPECT(x, v)	__builtin_expect(x, v)
@@ -21,58 +24,64 @@
 #endif
 
 /* Some color escape codes for pretty log messages */
-#define GRY(str)	"\e[30m" str "\e[0m" /**< Print str in gray */
-#define RED(str)	"\e[31m" str "\e[0m" /**< Print str in red */
-#define GRN(str)	"\e[32m" str "\e[0m" /**< Print str in green */
-#define YEL(str)	"\e[33m" str "\e[0m" /**< Print str in yellow */
-#define BLU(str)	"\e[34m" str "\e[0m" /**< Print str in blue */
-#define MAG(str)	"\e[35m" str "\e[0m" /**< Print str in magenta */
-#define CYN(str)	"\e[36m" str "\e[0m" /**< Print str in cyan */
-#define WHT(str)	"\e[37m" str "\e[0m" /**< Print str in white */
-#define BLD(str)	"\e[1m"  str "\e[0m" /**< Print str in bold */
+#ifndef ENABLE_OPAL_ASYNC
+ #define GRY(str)	"\e[30m" str "\e[0m" /**< Print str in gray */
+ #define RED(str)	"\e[31m" str "\e[0m" /**< Print str in red */
+ #define GRN(str)	"\e[32m" str "\e[0m" /**< Print str in green */
+ #define YEL(str)	"\e[33m" str "\e[0m" /**< Print str in yellow */
+ #define BLU(str)	"\e[34m" str "\e[0m" /**< Print str in blue */
+ #define MAG(str)	"\e[35m" str "\e[0m" /**< Print str in magenta */
+ #define CYN(str)	"\e[36m" str "\e[0m" /**< Print str in cyan */
+ #define WHT(str)	"\e[37m" str "\e[0m" /**< Print str in white */
+ #define BLD(str)	"\e[1m"  str "\e[0m" /**< Print str in bold */
 
-#define GFX(chr)	"\e(0" chr "\e(B"
-#define UP(n)		"\e[" ## n ## "A"
-#define DOWN(n)	 	"\e[" ## n ## "B"
-#define RIGHT(n)	"\e[" ## n ## "C"
-#define LEFT(n)	 	"\e[" ## n ## "D"
+ #define GFX(chr)	"\e(0" chr "\e(B"
+ #define UP(n)		"\e[" ## n ## "A"
+ #define DOWN(n)	 "\e[" ## n ## "B"
+ #define RIGHT(n)	"\e[" ## n ## "C"
+ #define LEFT(n)	 "\e[" ## n ## "D"
+#else
+ #define GRY(str)	str
+ #define RED(str)	str
+ #define GRN(str)	str
+ #define YEL(str)	str
+ #define BLU(str)	str
+ #define MAG(str)	str
+ #define CYN(str)	str
+ #define WHT(str)	str
+ #define BLD(str)	str
 
-#define ARRAY_LEN(a)	( sizeof a / sizeof a[0] )
+ #define GFX(chr)	" "
+ #define UP(n)		""
+ #define DOWN(n)	""
+ #define RIGHT(n)	""
+ #define LEFT(n)	""
+#endif
 
+/* CPP stringification */
+#define XSTR(x)		STR(x)
+#define  STR(x)		#x
+
+/** Calculate the number of elements in an array. */
+#define ARRAY_LEN(a)	( sizeof (a) / sizeof (a)[0] )
+
+/** Swap two values by using a local third one. */
 #define SWAP(a, b)	do { \
 	 			__typeof__(a) tmp = a; \
 				a = b; \
 				b = tmp; \
 			} while(0)
 
-/** The log level which is passed as first argument to print() */
-enum log_level { DEBUG, INFO, WARN, ERROR };
-
 /* Forward declarations */
 struct settings;
 struct timespec;
 
-/* These global variables allow changing the output style and verbosity */
-extern int _debug;
-extern int _indent;
-
-void outdent(int *old);
-
-#ifdef __GNUC__
- #define INDENT		int __attribute__ ((__cleanup__(outdent), unused)) _old_indent = _indent++;
-#else
- #define INDENT		;
-#endif
-
-/** Reset the wallclock of debugging outputs */
-void epoch_reset();
-
-/** Logs variadic messages to stdout.
- *
- * @param lvl The log level
- * @param fmt The format string (printf alike)
+/** The main thread id.
+ * This is used to notify the main thread about
+ * the program termination.
+ * See error() macros.
  */
-void print(enum log_level lvl, const char *fmt, ...);
+extern pthread_t _mtid;
 
 /** Safely append a format string to an existing string.
  *
@@ -99,14 +108,11 @@ double timespec_delta(struct timespec *start, struct timespec *end);
 /** Get period as timespec from rate */
 struct timespec timespec_rate(double rate);
 
-/** A system(2) emulator with popen/pclose(2) and proper output handling */
+/** A system(2) emulator with popen / pclose(2) and proper output handling */
 int system2(const char* cmd, ...);
 
-/** Append an element to a single linked list */
-#define list_add(list, elm) do { \
-		elm->next = list; \
-		list = elm; \
-	} while (0)
+/** Call quit() in the main thread. */
+void die();
 
 /** Check assertion and exit if failed. */
 #define assert(exp) do { \
@@ -116,42 +122,5 @@ int system2(const char* cmd, ...);
 		exit(EXIT_FAILURE); \
 	} } while (0)
 
-/** Printf alike debug message with level. */
-#define debug(lvl, msg, ...) do { \
-	if (lvl <= _debug) \
-		print(DEBUG, msg, ##__VA_ARGS__); \
-	} while (0)
-
-/** Printf alike info message. */
-#define info(msg, ...) do { \
-		print(INFO, msg, ##__VA_ARGS__); \
-	} while (0)
-
-/** Printf alike warning message. */
-#define warn(msg, ...) do { \
-		print(WARN, msg, ##__VA_ARGS__); \
-	} while (0)
-
-/** Print error and exit. */
-#define error(msg, ...) do { \
-		print(ERROR, msg, ##__VA_ARGS__); \
-		exit(EXIT_FAILURE); \
-	} while (0)
-
-/** Print error and strerror(errno). */
-#define serror(msg, ...) do { \
-		print(ERROR, msg ": %s", ##__VA_ARGS__, \
-			strerror(errno)); \
-		exit(EXIT_FAILURE); \
-	} while (0)
-
-/** Print configuration error and exit. */
-#define cerror(c, msg, ...) do { \
-		print(ERROR, msg " in %s:%u", ##__VA_ARGS__, \
-			(config_setting_source_file(c)) ? \
-			 config_setting_source_file(c) : "(stdio)", \
-			config_setting_source_line(c)); \
-		exit(EXIT_FAILURE); \
-	} while (0)
-
 #endif /* _UTILS_H_ */
+
diff --git a/server/src/cfg.c b/server/src/cfg.c
index 3060b3a56..6a3cf53ba 100644
--- a/server/src/cfg.c
+++ b/server/src/cfg.c
@@ -20,26 +20,25 @@
 
 #include "socket.h"
 #include "gtfpga.h"
+#ifdef ENABLE_OPAL_ASYNC
 #include "opal.h"
+#endif
 
 int config_parse(const char *filename, config_t *cfg, struct settings *set,
-	struct node **nodes, struct path **paths)
+	struct list *nodes, struct list *paths)
 {
 	config_set_auto_convert(cfg, 1);
 
-	FILE *file = (strcmp("-", filename)) ? fopen(filename, "r") : stdin;
-	if (!file)
-		error("Failed to open configuration file: %s", filename);
+	int  ret = strcmp("-", filename) ? config_read_file(cfg, filename)
+					 : config_read(cfg, stdin);
 
-	if (!config_read(cfg, file))
+	if (ret != CONFIG_TRUE)
 		error("Failed to parse configuration: %s in %s:%d",
-			config_error_text(cfg), filename,
+			config_error_text(cfg),
+			config_error_file(cfg) ? config_error_file(cfg) : filename,
 			config_error_line(cfg)
 		);
-
-	if (file != stdin)
-		fclose(file);
-
+	
 	config_setting_t *cfg_root = config_root_setting(cfg);
 
 	/* Parse global settings */
@@ -74,7 +73,7 @@ int config_parse(const char *filename, config_t *cfg, struct settings *set,
 		}
 	}
 
-	return CONFIG_TRUE;
+	return 0;
 }
 
 int config_parse_global(config_setting_t *cfg, struct settings *set)
@@ -88,11 +87,11 @@ int config_parse_global(config_setting_t *cfg, struct settings *set)
 
 	set->cfg = cfg;
 
-	return CONFIG_TRUE;
+	return 0;
 }
 
 int config_parse_path(config_setting_t *cfg,
-	struct path **paths, struct node **nodes)
+	struct list *paths, struct list *nodes)
 {
 	const char *in;
 	int enabled = 1;
@@ -106,9 +105,9 @@ int config_parse_path(config_setting_t *cfg,
 		cerror(cfg, "Invalid input node for path");
 	
 	in = config_setting_get_string(cfg_in);
-	p->in = node_lookup_name(in, *nodes);
+	p->in = node_lookup_name(in, nodes);
 	if (!p->in)
-		cerror(cfg_in, "Invalid input node '%s", in);
+		cerror(cfg_in, "Invalid input node '%s'", in);
 
 	/* Output node(s) */
 	struct config_setting_t *cfg_out = config_setting_get_member(cfg, "out");
@@ -141,7 +140,7 @@ int config_parse_path(config_setting_t *cfg,
 				warn("Using first destination '%s' as source for reverse path. "
 					"Ignoring remaining nodes", p->out->name);
 
-			struct path *r = alloc(sizeof(struct path));
+			struct path *r = path_create();
 
 			r->in  = p->out; /* Swap in/out */
 			r->out = p->in;
@@ -151,10 +150,10 @@ int config_parse_path(config_setting_t *cfg,
 			r->in->refcnt++;
 			r->out->refcnt++;
 
-			list_add(*paths, r);
+			list_push(paths, r);
 		}
 		
-		list_add(*paths, p);
+		list_push(paths, p);
 	}
 	else {
 		char buf[33];
@@ -167,14 +166,14 @@ int config_parse_path(config_setting_t *cfg,
 	return 0;
 }
 
-int config_parse_nodelist(config_setting_t *cfg, struct list *nodes, struct node **all) {
+int config_parse_nodelist(config_setting_t *cfg, struct list *nodes, struct list *all) {
 	const char *str;
 	struct node *node;
 	
 	switch (config_setting_type(cfg)) {
 		case CONFIG_TYPE_STRING:
 			str = config_setting_get_string(cfg);
-			node = node_lookup_name(str, *all);
+			node = node_lookup_name(str, all);
 			if (!node)
 				cerror(cfg, "Invalid outgoing node '%s'", str);
 				
@@ -184,7 +183,7 @@ int config_parse_nodelist(config_setting_t *cfg, struct list *nodes, struct node
 		case CONFIG_TYPE_ARRAY:
 			for (int i=0; i<config_setting_length(cfg); i++) {
 				str = config_setting_get_string_elem(cfg, i);
-				node = node_lookup_name(str, *all);
+				node = node_lookup_name(str, all);
 				if (!node)
 					cerror(config_setting_get_elem(cfg, i), "Invalid outgoing node '%s'", str);
 				
@@ -231,12 +230,12 @@ int config_parse_hooks(config_setting_t *cfg, struct list *hooks) {
 	return 0;
 }
 
-int config_parse_node(config_setting_t *cfg, struct node **nodes)
+int config_parse_node(config_setting_t *cfg, struct list *nodes)
 {
 	const char *type;
 	int ret;
 
-	struct node *n = alloc(sizeof(struct node));
+	struct node *n = node_create();
 
 	/* Required settings */
 	n->cfg = cfg;
@@ -244,42 +243,35 @@ int config_parse_node(config_setting_t *cfg, struct node **nodes)
 	if (!n->name)
 		cerror(cfg, "Missing node name");
 
-	if (config_setting_lookup_string(cfg, "type", &type)) {
-		n->vt = node_lookup_vtable(type);
-		if (!n->vt)
-			cerror(cfg, "Invalid type for node '%s'", n->name);
-
-		if (!n->vt->parse)
-			cerror(cfg, "Node type '%s' is not allowed in the config", type);
-	}
-	else
-		n->vt = node_lookup_vtable("udp");
+	if (!config_setting_lookup_string(cfg, "type", &type))
+		cerror(cfg, "Missing node name");
+		
+	n->vt = node_lookup_vtable(type);
+	if (!n->vt)
+		cerror(cfg, "Invalid type for node '%s'", n->name);
 
 	ret = n->vt->parse(cfg, n);
-
-	list_add(*nodes, n);
+	if (!ret)
+		list_push(nodes, n);
 
 	return ret;
 }
 
+#ifdef ENABLE_OPAL_ASYNC
 /** @todo: Remove this global variable. */
 extern struct opal_global *og;
 
 int config_parse_opal(config_setting_t *cfg, struct node *n)
 {	
 	if (!og) {
-		warn("Skipping this node, because this server is not running as an OPAL Async process!");
+		warn("Skipping node '%s', because this server is not running as an OPAL Async process!", n->name);
 		return -1;
 	}
 	
-	struct opal *o = (struct opal *) malloc(sizeof(struct opal));
-	if (!o)
-		error("Failed to allocate memory for opal settings");
-	
-	memset(o, 0, sizeof(struct opal));
+	struct opal *o = alloc(sizeof(struct opal));
 	
 	config_setting_lookup_int(cfg, "send_id", &o->send_id);
-	config_setting_lookup_int(cfg, "recv_id", &o->send_id);
+	config_setting_lookup_int(cfg, "recv_id", &o->recv_id);
 	config_setting_lookup_bool(cfg, "reply", &o->reply);
 		
 	/* Search for valid send and recv ids */
@@ -292,7 +284,7 @@ int config_parse_opal(config_setting_t *cfg, struct node *n)
 	if (!sfound)
 		cerror(config_setting_get_member(cfg, "send_id"), "Invalid send_id '%u' for node '%s'", o->send_id, n->name);
 	if (!rfound)
-		cerror(config_setting_get_member(cfg, "send_id"), "Invalid send_id '%u' for node '%s'", o->send_id, n->name);
+		cerror(config_setting_get_member(cfg, "recv_id"), "Invalid recv_id '%u' for node '%s'", o->recv_id, n->name);
 
 	n->opal = o;
 	n->opal->global = og;
@@ -300,12 +292,16 @@ int config_parse_opal(config_setting_t *cfg, struct node *n)
 
 	return 0;
 }
+#endif /* ENABLE_OPAL_ASYNC */
 
+
+#ifdef ENABLE_GTFPGA
 /** @todo Implement */
 int config_parse_gtfpga(config_setting_t *cfg, struct node *n)
 {
 	return 0;
 }
+#endif /* ENABLE_GTFPGA */
 
 int config_parse_socket(config_setting_t *cfg, struct node *n)
 {
@@ -333,14 +329,14 @@ int config_parse_socket(config_setting_t *cfg, struct node *n)
 	/** @todo Netem settings are not usable AF_UNIX */
 	config_setting_t *cfg_netem = config_setting_get_member(cfg, "netem");
 	if (cfg_netem) {
-		s->netem = (struct netem *) alloc(sizeof(struct netem));
+		s->netem = alloc(sizeof(struct netem));
 			
 		config_parse_netem(cfg_netem, s->netem);
 	}
 	
 	n->socket = s;
 
-	return CONFIG_TRUE;
+	return 0;
 }
 
 int config_parse_netem(config_setting_t *cfg, struct netem *em)
@@ -362,5 +358,5 @@ int config_parse_netem(config_setting_t *cfg, struct netem *em)
 
 	/** @todo Validate netem config values */
 
-	return CONFIG_TRUE;
+	return 0;
 }
diff --git a/server/src/hist.c b/server/src/hist.c
index cb20c0940..361375c41 100644
--- a/server/src/hist.c
+++ b/server/src/hist.c
@@ -17,7 +17,7 @@
 #define VAL(h, i)	((h)->low + (i) * (h)->resolution)
 #define INDEX(h, v)	round((v - (h)->low) / (h)->resolution)
 
-void hist_init(struct hist *h, double low, double high, double resolution)
+void hist_create(struct hist *h, double low, double high, double resolution)
 {
 	h->low = low;
 	h->high = high;
@@ -28,7 +28,7 @@ void hist_init(struct hist *h, double low, double high, double resolution)
 	hist_reset(h);
 }
 
-void hist_free(struct hist *h)
+void hist_destroy(struct hist *h)
 {
 	free(h->data);
 }
diff --git a/server/src/hooks.c b/server/src/hooks.c
index 5a0607aff..637328ce9 100644
--- a/server/src/hooks.c
+++ b/server/src/hooks.c
@@ -71,7 +71,7 @@ int hook_log(struct msg *m, struct path *p)
 		if (file)
 			debug(5, "Opened log file for path %s: %s", pstr, fstr);
 		
-		pthread_key_create(&pkey, (void (*)(void *)) fclose);
+		pthread_key_create(&pkey, (dtor_cb_t) fclose);
 		pthread_setspecific(pkey, file);
 	}
 	
@@ -127,8 +127,7 @@ int hook_fir(struct msg *m, struct path *p)
 		
 	/* Create thread local storage for circular history buffer */
 	if (!history) {
-		history = malloc(len * sizeof(float));
-		
+		history = alloc(len * sizeof(float));
 		pthread_key_create(&pkey, free);
 		pthread_setspecific(pkey, history);
 	}
diff --git a/server/src/if.c b/server/src/if.c
index a8c99207d..01eb104df 100644
--- a/server/src/if.c
+++ b/server/src/if.c
@@ -22,8 +22,8 @@
 #include "socket.h"
 #include "utils.h"
 
-/** Linked list of interfaces */
-struct interface *interfaces;
+/** Linked list of interfaces. */
+struct list interfaces;
 
 struct interface * if_create(int index) {
 	struct interface *i = alloc(sizeof(struct interface));
@@ -31,13 +31,22 @@ struct interface * if_create(int index) {
 	i->index = index;
 	if_indextoname(index, i->name);
 
-	debug(3, "Created interface '%s'", i->name, i->index, i->refcnt);
+	debug(3, "Created interface '%s' (index=%u)", i->name, i->index);
 
-	list_add(interfaces, i);
+	list_init(&i->sockets, NULL);
+	list_push(&interfaces, i);
 
 	return i;
 }
 
+void if_destroy(struct interface *i)
+{
+	/* List members are freed by their belonging nodes. */
+	list_destroy(&i->sockets);
+
+	free(i);
+}
+
 int if_start(struct interface *i, int affinity)
 { INDENT
 	if (!i->refcnt) {
@@ -49,7 +58,9 @@ int if_start(struct interface *i, int affinity)
 	
 	{ INDENT
 		int mark = 0;
-		for (struct socket *s = i->sockets; s; s = s->next) {
+		FOREACH(&i->sockets, it) {
+			struct socket *s = it->socket;
+
 			if (s->netem) {
 				s->mark = 1 + mark++;
 		
@@ -78,7 +89,7 @@ int if_start(struct interface *i, int affinity)
 
 int if_stop(struct interface *i)
 { INDENT
-	info("Stopping  interface '%s'", i->name);
+	info("Stopping interface '%s'", i->name);
 
 	{ INDENT
 		if_setaffinity(i, -1L);
@@ -171,10 +182,9 @@ int if_setaffinity(struct interface *i, int affinity)
 
 struct interface * if_lookup_index(int index)
 {
-	for (struct interface *i = interfaces; i; i = i->next) {
-		if (i->index == index) {
-			return i;
-		}
+	FOREACH(&interfaces, it) {
+		if (it->interface->index == index)
+			return it->interface;
 	}
 
 	return NULL;
diff --git a/server/src/list.c b/server/src/list.c
index d34c8beef..bfc5882cc 100644
--- a/server/src/list.c
+++ b/server/src/list.c
@@ -10,10 +10,11 @@
 #include "utils.h"
 #include "list.h"
 
-void list_init(struct list *l)
+void list_init(struct list *l, dtor_cb_t dtor)
 {
 	pthread_mutex_init(&l->lock, NULL);
 	
+	l->destructor = dtor;
 	l->count = 0;
 	l->head = NULL;
 	l->tail = NULL;
@@ -26,11 +27,15 @@ void list_destroy(struct list *l)
 	struct list_elm *elm = l->head;
 	while (elm) {
 		struct list_elm *tmp = elm;
-		free(tmp);
-
 		elm = elm->next;
+
+		if (l->destructor)
+			l->destructor(tmp->ptr);
+
+		free(tmp);
 	}
 	
+	pthread_mutex_unlock(&l->lock);
 	pthread_mutex_destroy(&l->lock);
 }
 
diff --git a/server/src/log.c b/server/src/log.c
new file mode 100644
index 000000000..61a30abee
--- /dev/null
+++ b/server/src/log.c
@@ -0,0 +1,75 @@
+/** Logging and debugging routines
+ *
+ * @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
+ * @copyright 2015, Institute for Automation of Complex Power Systems, EONERC
+ */
+
+ #include <stdio.h>
+#include <time.h>
+
+#include "log.h"
+#include "utils.h"
+
+int _debug = V;
+
+static struct timespec epoch;
+
+#ifdef __GNUC__
+static __thread int indent = 0;
+
+/** Get thread-specific pointer to indent level */
+int log_indent(int levels)
+{
+	int old = indent;
+	indent += levels;
+	return old;
+}
+
+void log_outdent(int *old)
+{
+	indent = *old;
+}
+#endif
+
+void log_reset()
+{
+	clock_gettime(CLOCK_REALTIME, &epoch);
+}
+
+void log_print(enum log_level lvl, const char *fmt, ...)
+{
+	struct timespec ts;
+	char buf[512] = "";
+
+	va_list ap;
+
+	/* Timestamp */
+	clock_gettime(CLOCK_REALTIME, &ts);
+	strap(buf, sizeof(buf), "%8.3f ", timespec_delta(&epoch, &ts));
+
+	/* Severity */
+	switch (lvl) {
+		case DEBUG: strap(buf, sizeof(buf), BLD("%-5s "), GRY("Debug")); break;
+		case INFO:  strap(buf, sizeof(buf), BLD("%-5s "),     "     " ); break;
+		case WARN:  strap(buf, sizeof(buf), BLD("%-5s "), YEL(" Warn")); break;
+		case ERROR: strap(buf, sizeof(buf), BLD("%-5s "), RED("Error")); break;
+	}
+
+	/* Indention */
+#ifdef __GNUC__
+	for (int i = 0; i < indent; i++)
+		strap(buf, sizeof(buf), GFX("\x78") " ");
+	strap(buf, sizeof(buf), GFX("\x74") " ");
+#endif
+
+	/* Format String */
+	va_start(ap, fmt);
+	vstrap(buf, sizeof(buf), fmt, ap);
+	va_end(ap);
+	
+	/* Output */
+#ifdef ENABLE_OPAL_ASYNC
+	OpalPrint("S2SS: %s\n", buf);
+#endif
+	fprintf(stderr, "\r%s\n", buf);
+}
diff --git a/server/src/node.c b/server/src/node.c
index 7ad615eea..a5497b2b7 100644
--- a/server/src/node.c
+++ b/server/src/node.c
@@ -13,7 +13,9 @@
 /* Node types */
 #include "socket.h"
 #include "gtfpga.h"
+#ifdef ENABLE_OPAL_ASYNC
 #include "opal.h"
+#endif
 
 #define VTABLE(type, name, fnc) { type, name, config_parse_ ## fnc, \
 				  fnc ## _print, \
@@ -35,14 +37,14 @@ static const struct node_vtable vtables[] = {
 	VTABLE(TCPD,	   "tcpd",	socket)
 };
 
-/** Linked list of nodes */
-struct node *nodes;
+/** Linked list of nodes. */
+struct list nodes;
 
-struct node * node_lookup_name(const char *str, struct node *nodes)
+struct node * node_lookup_name(const char *str, struct list *nodes)
 {
-	for (struct node *n = nodes; n; n = n->next) {
-		if (!strcmp(str, n->name))
-			return n;
+	FOREACH(nodes, it) {
+		if (!strcmp(str, it->node->name))
+			return it->node;
 	}
 
 	return NULL;
@@ -59,7 +61,7 @@ struct node_vtable const * node_lookup_vtable(const char *str)
 }
 
 int node_start(struct node *n)
-{
+{ INDENT
 	if (!n->refcnt) {
 		warn("Node '%s' is unused. Skipping...", n->name);
 		return -1;
@@ -97,7 +99,7 @@ int node_start_defer(struct node *n)
 }
 
 int node_stop(struct node *n)
-{
+{ INDENT
 	int ret;
 	info("Stopping node '%s'", n->name);
 	
@@ -108,7 +110,7 @@ int node_stop(struct node *n)
 	return ret;
 }
 
-int node_reverse(struct node *n)
+void node_reverse(struct node *n)
 {
 	switch (n->vt->type) {
 		case IEEE_802_3:
@@ -119,5 +121,24 @@ int node_reverse(struct node *n)
 			break;
 		default: { }
 	}
-	return n->vt->open == socket_open;
+}
+
+struct node * node_create()
+{
+	return alloc(sizeof(struct node));
+}
+
+void node_destroy(struct node *n)
+{
+	switch (n->vt->type) {
+		case IEEE_802_3:
+		case IP:
+		case UDP:
+		case TCP:
+			free(n->socket->netem);
+		default: { }
+	}
+
+	free(n->socket);
+	free(n);
 }
diff --git a/server/src/opal.c b/server/src/opal.c
index 44fb41a4a..b7783aa05 100644
--- a/server/src/opal.c
+++ b/server/src/opal.c
@@ -22,11 +22,7 @@ int opal_init(int argc, char *argv[])
 	if (argc != 4)
 		return -1;
 
-	struct opal_global *g = (struct opal_global *) malloc(sizeof(struct opal_global));
-	if (!g)
-		error("Failed to allocate memory for global OPAL settings");
-	
-	memset(g, 0, sizeof(struct opal_global));
+	struct opal_global *g = alloc(sizeof(struct opal_global));
 	
 	pthread_mutex_init(&g->lock, NULL);
 	
@@ -48,20 +44,20 @@ int opal_init(int argc, char *argv[])
 	/* Get list of Send and RecvIDs */
 	if ((err = OpalGetNbAsyncSendIcon(&g->send_icons)) != EOK)
 		error("Failed to get number of send blocks (%d)", err);
-	if ((err = OpalGetNbAsyncRecvIcon(&g->recv_icons)) != EOK);
+	if ((err = OpalGetNbAsyncRecvIcon(&g->recv_icons)) != EOK)
 		error("Failed to get number of recv blocks (%d)", err);
 	
-	g->send_ids = (int *) malloc(g->send_icons * sizeof(int));
-	g->recv_ids = (int *) malloc(g->recv_icons * sizeof(int));
-	if (!g->send_ids || !g->recv_ids)
-		error("Failed to allocate memory for OPAL AsyncApi ID list.");
+	g->send_ids = alloc(g->send_icons * sizeof(int));
+	g->recv_ids = alloc(g->recv_icons * sizeof(int));
 	
-	if ((err = OpalGetAsyncSendIDList(g->send_ids, g->send_icons)) != EOK)
+	if ((err = OpalGetAsyncSendIDList(g->send_ids, g->send_icons * sizeof(int))) != EOK)
 		error("Failed to get list of send ids (%d)", err);
-	if ((err = OpalGetAsyncRecvIDList(g->recv_ids, g->recv_icons)) != EOK)
+	if ((err = OpalGetAsyncRecvIDList(g->recv_ids, g->recv_icons * sizeof(int))) != EOK)
 		error("Failed to get list of recv ids (%d)", err);
 	
-	info("Started as OPAL async process:");
+	info("Started as OPAL Asynchronous process");
+	info("This is Simulator2Simulator Server (S2SS) %s (built on %s, %s, debug=%d)",
+		VERSION, __DATE__, __TIME__, _debug);
 	opal_print_global(g);
 	
 	og = g;
@@ -73,18 +69,22 @@ int opal_deinit()
 {
 	int err;
 
-	if (og) {
-		if ((err = OpalCloseAsyncMem(og->async_shmem_size, og->async_shmem_name)) != EOK)
-			error("Failed to close shared memory area (%d)", err);
-		if ((err = OpalSystemCtrl_UnRegister(og->print_shmem_name)) != EOK)
-			error("Failed to close shared memory for system control (%d)", err);
+	if (!og)
+		return 0;
+	
+	if ((err = OpalCloseAsyncMem(og->async_shmem_size, og->async_shmem_name)) != EOK)
+		error("Failed to close shared memory area (%d)", err);
+	
+	debug(4, "Closing OPAL shared memory mapping");
+	
+	if ((err = OpalSystemCtrl_UnRegister(og->print_shmem_name)) != EOK)
+		error("Failed to close shared memory for system control (%d)", err);
 		
-		free(og->send_ids);
-		free(og->recv_ids);
-		free(og);
+	free(og->send_ids);
+	free(og->recv_ids);
+	free(og);
 
-		og = NULL;
-	}
+	og = NULL;
 	
 	return 0;
 }
@@ -99,15 +99,15 @@ int opal_print_global(struct opal_global *g)
 	for (int i=0; i<g->recv_icons; i++)
 		strap(rbuf, sizeof(rbuf), "%u ", g->recv_ids[i]);
 	
-	debug(4, "Controller ID: %u", g->params.controllerID);
-	debug(4, "Send Blocks: %s",    sbuf);
-	debug(4, "Receive Blocks: %s", rbuf);
+	debug(2, "Controller ID: %u", g->params.controllerID);
+	debug(2, "Send Blocks: %s",    sbuf);
+	debug(2, "Receive Blocks: %s", rbuf);
 
-	debug(4, "Control Block Parameters:");
+	debug(2, "Control Block Parameters:");
 	for (int i=0; i<GENASYNC_NB_FLOAT_PARAM; i++)
-		debug(4, "FloatParam[]%u] = %f", i, g->params.FloatParam[i]);
+		debug(2, "FloatParam[]%u] = %f", i, g->params.FloatParam[i]);
 	for (int i=0; i<GENASYNC_NB_STRING_PARAM; i++)
-		debug(4, "StringParam[%u] = %s", i, g->params.StringParam[i]);
+		debug(2, "StringParam[%u] = %s", i, g->params.StringParam[i]);
 	
 	return 0;
 }
@@ -151,9 +151,9 @@ int opal_read(struct node *n, struct msg *m)
 	do {
 		if ((ret = OpalWaitForAsyncSendRequest(&id)) != EOK) {
 			state = OpalGetAsyncModelState();
-			if ((state != STATE_RESET) && (state != STATE_STOP)) {
-				OpalSetAsyncSendIconError(ret, id);
-				info("OpalWaitForAsyncSendRequest(), errno %d", ret);
+			if ((state == STATE_RESET) || (state == STATE_STOP)) {
+				warn("OpalGetAsyncModelState(): Model stopped or resetted!");
+				die();
 			}
 
 			return -1; // FIXME: correct return value
@@ -193,8 +193,10 @@ int opal_read(struct node *n, struct msg *m)
 	/* Before continuing, we make sure that the real-time model
 	 * has not been stopped. If it has, we quit. */
 	state = OpalGetAsyncModelState();
-	if ((state == STATE_RESET) || (state == STATE_STOP))
-		error("OpalGetAsyncModelState(): Model stopped or resetted!"); // TODO: fixme
+	if ((state == STATE_RESET) || (state == STATE_STOP)) {
+		warn("OpalGetAsyncModelState(): Model stopped or resetted!");
+		die();
+	}
 
 	return 0;
 }
@@ -209,8 +211,10 @@ int opal_write(struct node *n, struct msg *m)
 	double data[MSG_VALUES] = { NAN };
 	
 	state = OpalGetAsyncModelState();
-	if ((state == STATE_RESET) || (state == STATE_STOP))
-		return -1;
+	if ((state == STATE_RESET) || (state == STATE_STOP)) {
+		warn("OpalGetAsyncModelState(): Model stopped or resetted!");
+		die();
+	}
 
 	OpalSetAsyncRecvIconStatus(m->sequence, o->recv_id);	/* Set the Status to the message ID */
 	OpalSetAsyncRecvIconError(0, o->recv_id);		/* Set the Error to 0 */
diff --git a/server/src/path.c b/server/src/path.c
index a697ae2a0..c08810433 100644
--- a/server/src/path.c
+++ b/server/src/path.c
@@ -16,17 +16,19 @@
 #include "utils.h"
 #include "path.h"
 
-#define sigev_notify_thread_id   _sigev_un._tid
+#ifndef sigev_notify_thread_id
+ #define sigev_notify_thread_id   _sigev_un._tid
+#endif
 
-/** Linked list of paths */
-struct path *paths;
+/** Linked list of paths. */
+struct list paths;
 
 /** Send messages asynchronously */
 static void * path_send(void *arg)
 {
+	struct path *p = arg;
+
 	int sig;
-	struct path *p = (struct path *) arg;
-	timer_t tmr;
 	sigset_t set;
 
 	struct sigevent sev = {
@@ -45,22 +47,19 @@ static void * path_send(void *arg)
 	if(pthread_sigmask(SIG_BLOCK, &set, NULL))
 		serror("Set signal mask");
 
-	if (timer_create(CLOCK_REALTIME, &sev, &tmr))
+	if (timer_create(CLOCK_REALTIME, &sev, &p->timer))
 		serror("Failed to create timer");
 
-	if (timer_settime(tmr, 0, &its, NULL))
+	if (timer_settime(p->timer, 0, &its, NULL))
 		serror("Failed to start timer");
 
 	while (1) {
 		sigwait(&set, &sig); /* blocking wait for next timer tick */
 		
-		if (p->received) {
-			FOREACH(&p->destinations, it) {
-				node_write(it->node, p->last);
-			}
-			
-			p->sent++;
-		}
+		FOREACH(&p->destinations, it)
+			node_write(it->node, p->current);
+
+		p->sent++;
 	}
 
 	return NULL;
@@ -69,43 +68,48 @@ static void * path_send(void *arg)
 /** Receive messages */
 static void * path_run(void *arg)
 {
-	char buf[33];
 	struct path *p = arg;
-	struct msg  *m = alloc(sizeof(struct msg));
-	if (!m)
-		error("Failed to allocate memory for message!");
+
+	p->previous = alloc(sizeof(struct msg));
+	p->current  = alloc(sizeof(struct msg));
 	
+	char buf[33];
+
 	/* Open deferred TCP connection */
 	node_start_defer(p->in);
 	// FIXME: node_start_defer(p->out);
 
+
 	/* Main thread loop */
 	while (1) {
-		node_read(p->in, m); /* Receive message */
+		node_read(p->in, p->current); /* Receive message */
 		
 		p->received++;
 
 		/* Check header fields */
-		if (m->version != MSG_VERSION ||
-		    m->type    != MSG_TYPE_DATA) {
+		if (p->current->version != MSG_VERSION ||
+		    p->current->type    != MSG_TYPE_DATA) {
 			p->invalid++;
 			continue;
 		}
 
 		/* Update histogram */
-		int dist = (UINT16_MAX + m->sequence - p->sequence) % UINT16_MAX;
+		int dist = (UINT16_MAX + p->current->sequence - p->previous->sequence) % UINT16_MAX;
 		if (dist > UINT16_MAX / 2)
 			dist -= UINT16_MAX;
 
 		hist_put(&p->histogram, dist);
 
 		/* Handle simulation restart */
-		if (m->sequence == 0 && abs(dist) >= 1) {
-			path_print(p, buf, sizeof(buf));
-			path_stats(p);
-			
-			warn("Simulation for path %s restarted (p->seq=%u, m->seq=%u, dist=%d)",
-				buf, p->sequence, m->sequence, dist);
+		if (p->current->sequence == 0 && abs(dist) >= 1) {
+			if (p->received) {
+				path_print_stats(p);
+				hist_print(&p->histogram);
+			}
+
+			path_print(p, buf, sizeof(buf));			
+			warn("Simulation for path %s restarted (prev->seq=%u, current->seq=%u, dist=%d)",
+				buf, p->previous->sequence, p->current->sequence, dist);
 
 			/* Reset counters */
 			p->sent		= 0;
@@ -114,7 +118,6 @@ static void * path_run(void *arg)
 			p->skipped	= 0;
 			p->dropped	= 0;
 
-			hist_print(&p->histogram);
 			hist_reset(&p->histogram);
 		}
 		else if (dist <= 0 && p->received > 1) {
@@ -124,27 +127,22 @@ static void * path_run(void *arg)
 
 		/* Call hook callbacks */
 		FOREACH(&p->hooks, it) {
-			if (it->hook(m, p)) {
+			if (it->hook(p->current, p)) {
 				p->skipped++;
 				continue;
 			}
 		}
 
-		/* Update last known sequence number */
-		p->sequence = m->sequence;
-		p->last = m;
-
 		/* At fixed rate mode, messages are send by another thread */
 		if (!p->rate) {
-			FOREACH(&p->destinations, it) {
-				node_write(it->node, m);
-			}
-			
+			FOREACH(&p->destinations, it)
+				node_write(it->node, p->current);
+
 			p->sent++;
 		}
-	}
 
-	free(m);
+		SWAP(p->previous, p->current);
+	}
 
 	return NULL;
 }
@@ -156,13 +154,11 @@ int path_start(struct path *p)
 	
 	info("Starting path: %s", buf);
 
-	hist_init(&p->histogram, -HIST_SEQ, +HIST_SEQ, 1);
-
 	/* At fixed rate mode, we start another thread for sending */
 	if (p->rate)
-		pthread_create(&p->sent_tid, NULL, &path_send, (void *) p);
+		pthread_create(&p->sent_tid, NULL, &path_send, p);
 
-	return  pthread_create(&p->recv_tid, NULL, &path_run,  (void *) p);
+	return  pthread_create(&p->recv_tid, NULL, &path_run,  p);
 }
 
 int path_stop(struct path *p)
@@ -178,25 +174,23 @@ int path_stop(struct path *p)
 	if (p->rate) {
 		pthread_cancel(p->sent_tid);
 		pthread_join(p->sent_tid, NULL);
+
+		timer_delete(p->timer);
 	}
 
-	if (p->sent || p->received) {
-		path_stats(p);
+	if (p->received)
 		hist_print(&p->histogram);
-		hist_free(&p->histogram);
-	}
 
 	return 0;
 }
 
-void path_stats(struct path *p)
+void path_print_stats(struct path *p)
 {
 	char buf[33];
 	path_print(p, buf, sizeof(buf));
 	
-	info("%-32s :   %-8u %-8u %-8u %-8u %-8u",
-		buf, p->sent, p->received, p->dropped, p->skipped, p->invalid
-	);
+	info("%-32s :   %-8u %-8u %-8u %-8u %-8u", buf,
+		p->sent, p->received, p->dropped, p->skipped, p->invalid);
 }
 
 int path_print(struct path *p, char *buf, int len)
@@ -215,10 +209,25 @@ int path_print(struct path *p, char *buf, int len)
 	return 0;
 }
 
-int path_destroy(struct path *p)
+struct path * path_create()
+{
+	struct path *p = alloc(sizeof(struct path));
+
+	list_init(&p->destinations, NULL);
+	list_init(&p->hooks, NULL);
+
+	hist_create(&p->histogram, -HIST_SEQ, +HIST_SEQ, 1);
+
+	return p;
+}
+
+void path_destroy(struct path *p)
 {
 	list_destroy(&p->destinations);
 	list_destroy(&p->hooks);
+	hist_destroy(&p->histogram);
 	
-	return 0;
+	free(p->current);
+	free(p->previous);
+	free(p);
 }
diff --git a/server/src/random.c b/server/src/random.c
index 7e3849cd6..4d08c0844 100644
--- a/server/src/random.c
+++ b/server/src/random.c
@@ -22,7 +22,7 @@
 
 void tick(int sig, siginfo_t *si, void *ptr)
 {
-	struct msg *m = (struct msg*) si->si_value.sival_ptr;
+	struct msg *m = (struct msg *) si->si_value.sival_ptr;
 
 	msg_random(m);
 	msg_fprint(stdout, m);
@@ -37,9 +37,12 @@ int main(int argc, char *argv[])
 		printf("Usage: %s VALUES RATE\n", argv[0]);
 		printf("  VALUES is the number of values a message contains\n");
 		printf("  RATE   how many messages per second\n\n");
-		printf("Simulator2Simulator Server %s (built on %s %s)\n", BLU(VERSION), MAG(__DATE__), MAG(__TIME__));
-		printf(" Copyright 2014, Institute for Automation of Complex Power Systems, EONERC\n");
-		printf("   Steffen Vogel <stvogel@eonerc.rwth-aachen.de>\n");
+
+		printf("Simulator2Simulator Server %s (built on %s %s)\n",
+			BLU(VERSION), MAG(__DATE__), MAG(__TIME__));
+		printf(" Copyright 2015, Institute for Automation of Complex Power Systems, EONERC\n");
+		printf(" Steffen Vogel <StVogel@eonerc.rwth-aachen.de>\n");
+
 		exit(EXIT_FAILURE);
 	}
 
diff --git a/server/src/receive.c b/server/src/receive.c
index 18f131c0e..378311073 100644
--- a/server/src/receive.c
+++ b/server/src/receive.c
@@ -24,7 +24,7 @@
 
 static struct settings set;
 static struct msg msg = MSG_INIT(0);
-extern struct node *nodes;
+extern struct list nodes;
 static struct node *node;
 
 void quit(int sig, siginfo_t *si, void *ptr)
@@ -35,13 +35,16 @@ void quit(int sig, siginfo_t *si, void *ptr)
 
 void usage(char *name)
 {
-	printf("Usage: %s CONFIG NODE\n", name);
+	printf("Usage: %s [-r] CONFIG NODE\n", name);
+	printf("  -r      swap local / remote address of socket based nodes)\n\n");
 	printf("  CONFIG  path to a configuration file\n");
 	printf("  NODE    name of the node which shoud be used\n\n");
+
 	printf("Simulator2Simulator Server %s (built on %s %s)\n",
 		BLU(VERSION), MAG(__DATE__), MAG(__TIME__));
-	printf(" Copyright 2014, Institute for Automation of Complex Power Systems, EONERC\n");
-	printf("   Steffen Vogel <stvogel@eonerc.rwth-aachen.de>\n");
+	printf(" Copyright 2015, Institute for Automation of Complex Power Systems, EONERC\n");
+	printf(" Steffen Vogel <StVogel@eonerc.rwth-aachen.de>\n");
+
 	exit(EXIT_FAILURE);
 }
 
@@ -76,7 +79,7 @@ int main(int argc, char *argv[])
 	config_init(&config);
 	config_parse(argv[optind], &config, &set, &nodes, NULL);
 	
-	node = node_lookup_name(argv[optind+1], nodes);
+	node = node_lookup_name(argv[optind+1], &nodes);
 	if (!node)
 		error("There's no node with the name '%s'", argv[optind+1]);
 
diff --git a/server/src/send.c b/server/src/send.c
index 2dd7bae2a..a4f841e7a 100644
--- a/server/src/send.c
+++ b/server/src/send.c
@@ -27,7 +27,7 @@
 static struct settings set;
 static struct msg  msg = MSG_INIT(0);
 static struct node *node;
-extern struct node *nodes;
+extern struct list nodes;
 
 void quit(int sig, siginfo_t *si, void *ptr)
 {
@@ -38,13 +38,15 @@ void quit(int sig, siginfo_t *si, void *ptr)
 void usage(char *name)
 {
 	printf("Usage: %s [-r] CONFIG NODE\n", name);
-	printf("  -r      swap local / remote address of socket based nodes)\n");
+	printf("  -r      swap local / remote address of socket based nodes)\n\n");
 	printf("  CONFIG  path to a configuration file\n");
 	printf("  NODE    name of the node which shoud be used\n");
+
 	printf("Simulator2Simulator Server %s (built on %s %s)\n",
 		BLU(VERSION), MAG(__DATE__), MAG(__TIME__));
-	printf(" Copyright 2014, Institute for Automation of Complex Power Systems, EONERC\n");
-	printf("   Steffen Vogel <stvogel@eonerc.rwth-aachen.de>\n");
+	printf(" Copyright 2015, Institute for Automation of Complex Power Systems, EONERC\n");
+	printf(" Steffen Vogel <StVogel@eonerc.rwth-aachen.de>\n");
+
 	exit(EXIT_FAILURE);
 }
 
@@ -79,7 +81,7 @@ int main(int argc, char *argv[])
 	config_init(&config);
 	config_parse(argv[optind], &config, &set, &nodes, NULL);
 	
-	node = node_lookup_name(argv[optind+1], nodes);
+	node = node_lookup_name(argv[optind+1], &nodes);
 	if (!node)
 		error("There's no node with the name '%s'", argv[optind+1]);
 	
diff --git a/server/src/server.c b/server/src/server.c
index 9513ca02e..ccd1e1018 100644
--- a/server/src/server.c
+++ b/server/src/server.c
@@ -27,55 +27,52 @@
 #endif
 
 /** Linked list of nodes */
-extern struct node *nodes;
+extern struct list nodes;
 /** Linked list of paths */
-extern struct path *paths;
+extern struct list paths;
 /** Linked list of interfaces */
-extern struct interface *interfaces;
+extern struct list interfaces;
 
 /** The global configuration */
-struct settings settings;
-config_t config;
+static struct settings settings;
+static config_t config;
 
 static void quit()
-{ _indent = 0;
+{
 	info("Stopping paths:");
-	for (struct path *p = paths; p; p = p->next) { INDENT
-		path_stop(p);
-		path_destroy(p);
-	}
+	FOREACH(&paths, it)
+		path_stop(it->path);
 
 	info("Stopping nodes:");
-	for (struct node *n = nodes; n; n = n->next) { INDENT
-		node_stop(n);
-	}
+	FOREACH(&nodes, it)
+		node_stop(it->node);
 
 	info("Stopping interfaces:");
-	for (struct interface *i = interfaces; i; i = i->next) { INDENT
-		if_stop(i);
-	}
+	FOREACH(&interfaces, it)
+		if_stop(it->interface);
 
-	/** @todo Free nodes */
+#ifdef ENABLE_OPAL_ASYNC
+	opal_deinit();
+#endif
 
+	/* Freeing dynamically allocated memory */
+	list_destroy(&paths);
+	list_destroy(&nodes);
+	list_destroy(&interfaces);
 	config_destroy(&config);
 
+	info("Goodbye!");
+
 	_exit(EXIT_SUCCESS);
 }
 
 void realtime_init()
 { INDENT
-	/* Check for realtime kernel patch */
-	struct stat st;
-	if (stat("/sys/kernel/realtime", &st))
-		warn("Use a RT-preempt patched Linux for lower latencies!");
-	else
-		info("Server is running on a realtime patched kernel");
-
-	/* Use FIFO scheduler with realtime priority */
+	/* Use FIFO scheduler with real time priority */
 	if (settings.priority) {
 		struct sched_param param = { .sched_priority = settings.priority };
 		if (sched_setscheduler(0, SCHED_FIFO, &param))
-			serror("Failed to set realtime priority");
+			serror("Failed to set real time priority");
 		else
 			debug(3, "Set task priority to %u", settings.priority);
 	}
@@ -99,9 +96,9 @@ void signals_init()
 	};
 
 	sigemptyset(&sa_quit.sa_mask);
+	sigaction(SIGQUIT, &sa_quit, NULL);
 	sigaction(SIGTERM, &sa_quit, NULL);
 	sigaction(SIGINT, &sa_quit, NULL);
-	atexit(&quit);
 }
 
 void usage(const char *name)
@@ -113,14 +110,18 @@ void usage(const char *name)
 	printf("  This type of invocation is used by OPAL-RT Asynchronous processes.\n");
 	printf("  See in the RT-LAB User Guide for more information.\n\n");
 #endif
-	printf("Simulator2Simulator Server %s (built on %s, %s)\n",
+	printf("Simulator2Simulator Server %s (built on %s %s)\n",
 		BLU(VERSION), MAG(__DATE__), MAG(__TIME__));
-	
+	printf(" Copyright 2015, Institute for Automation of Complex Power Systems, EONERC\n");
+	printf(" Steffen Vogel <StVogel@eonerc.rwth-aachen.de>\n");
+
 	exit(EXIT_FAILURE);
 }
 
 int main(int argc, char *argv[])
 {
+	_mtid = pthread_self();
+
 	/* Check arguments */
 #ifdef ENABLE_OPAL_ASYNC
 	if (argc != 2 && argc != 4)
@@ -128,28 +129,37 @@ int main(int argc, char *argv[])
 	if (argc != 2)
 #endif
 		usage(argv[0]);
-	
-	epoch_reset();
-	info("This is Simulator2Simulator Server (S2SS) %s (built on %s, %s)",
-		BLD(YEL(VERSION)), BLD(MAG(__DATE__)), BLD(MAG(__TIME__)));
 
-	char *configfile = argv[1];
+	info("This is Simulator2Simulator Server (S2SS) %s (built on %s, %s, debug=%d)",
+		BLD(YEL(VERSION)), BLD(MAG(__DATE__)), BLD(MAG(__TIME__)), _debug);
 
 	/* Check priviledges */
 	if (getuid() != 0)
 		error("The server requires superuser privileges!");
 
-	/* Start initialization */
+	/* Initialize lists */
+	list_init(&nodes, (dtor_cb_t) node_destroy);
+	list_init(&paths, (dtor_cb_t) path_destroy);
+	list_init(&interfaces, (dtor_cb_t) if_destroy);
+
+
 	info("Initialize realtime system:");
 	realtime_init();
+
 	info("Setup signals:");
 	signals_init();
+
 	info("Parsing configuration:");
 	config_init(&config);
 
 #ifdef ENABLE_OPAL_ASYNC
-	/* Check if called as asynchronous process from RT-LAB */
+	/* Check if called we are called as an asynchronous process from RT-LAB. */
 	opal_init(argc, argv);
+
+	/* @todo: look in predefined locations for a file */
+	char *configfile = "opal-shmem.conf";
+#else
+	char *configfile = argv[1];
 #endif
 
 	/* Parse configuration and create nodes/paths */
@@ -157,40 +167,34 @@ int main(int argc, char *argv[])
 
 	/* Connect all nodes and start one thread per path */
 	info("Starting nodes:");
-	for (struct node *n = nodes; n; n = n->next) { INDENT
-		node_start(n);
-	}
+	FOREACH(&nodes, it)
+		node_start(it->node);
 
 	info("Starting interfaces:");
-	for (struct interface *i = interfaces; i; i = i->next) { INDENT
-		if_start(i, settings.affinity);
-	}
+	FOREACH(&interfaces, it)
+		if_start(it->interface, settings.affinity);
 
-	info("Starting pathes:");
-	for (struct path *p = paths; p; p = p->next) { INDENT
-		path_start(p);
-	}
+	info("Starting paths:");
+	FOREACH(&paths, it)
+		path_start(it->path);
 
 	/* Run! */
 	if (settings.stats > 0) {
-		struct path *p = paths;
-
 		info("Runtime Statistics:");
 		info("%-32s :   %-8s %-8s %-8s %-8s %-8s",
 			"Source " MAG("=>") " Destination", "#Sent", "#Recv", "#Drop", "#Skip", "#Inval");
 		info("---------------------------------------------------------------------------");
 
-		while (1) {
+		do { FOREACH(&paths, it) {
 			usleep(settings.stats * 1e6);
-			path_stats(p);
+			path_print_stats(it->path);
+		} } while (1);
 
-			p = (p->next) ? p->next : paths; 
-		}
 	}
 	else
 		pause();
 
-	/* Note: quit() is called by exit handler! */
+	quit();
 
 	return 0;
 }
diff --git a/server/src/socket.c b/server/src/socket.c
index bfab7155e..3e4fc85d6 100644
--- a/server/src/socket.c
+++ b/server/src/socket.c
@@ -34,8 +34,8 @@ int socket_print(struct node *n, char *buf, int len)
 	char local[INET6_ADDRSTRLEN + 16];
 	char remote[INET6_ADDRSTRLEN + 16];
 	
-	socket_print_addr(local, sizeof(local), (struct sockaddr*) &s->local);
-	socket_print_addr(remote, sizeof(remote), (struct sockaddr*) &s->remote);
+	socket_print_addr(local, sizeof(local), (struct sockaddr *) &s->local);
+	socket_print_addr(remote, sizeof(remote), (struct sockaddr *) &s->remote);
 
 	return snprintf(buf, len, "local=%s, remote=%s", local, remote);
 }
@@ -86,7 +86,7 @@ int socket_open(struct node *n)
 	if (!i)
 		i = if_create(index);
 
-	list_add(i->sockets, s);
+	list_push(&i->sockets, s);
 	i->refcnt++;
 
 	/* Set socket priority, QoS or TOS IP options */
@@ -230,7 +230,7 @@ int socket_parse_addr(const char *addr, struct sockaddr *sa, enum node_type type
 	else {	/* Format: "192.168.0.10:12001" */
 		struct addrinfo hint = {
 			.ai_flags = flags,
-			.ai_family = AF_UNSPEC
+			.ai_family = AF_INET
 		};
 		
 		/* Split string */
diff --git a/server/src/test.c b/server/src/test.c
index 594732f36..2deec58bf 100644
--- a/server/src/test.c
+++ b/server/src/test.c
@@ -26,7 +26,7 @@
 
 static struct settings set;
 static struct node *node;
-extern struct node *nodes;
+extern struct list nodes;
 
 /* Test options */
 int running = 1;
@@ -48,7 +48,7 @@ double high = 2e-4;
 /** Histogram resolution. */
 double res = 1e-5;
 
-#define CLOCK_ID	CLOCK_MONOTONIC_RAW
+#define CLOCK_ID	CLOCK_MONOTONIC
 
 /* Prototypes */
 void test_rtt();
@@ -67,10 +67,12 @@ int main(int argc, char *argv[])
 		printf("  CONFIG  path to a configuration file\n");
 		printf("  TEST    the name of the test to execute: 'rtt'\n");
 		printf("  NODE    name of the node which shoud be used\n\n");
+
 		printf("Simulator2Simulator Server %s (built on %s %s)\n",
 			BLU(VERSION), MAG(__DATE__), MAG(__TIME__));
-		printf(" Copyright 2014, Institute for Automation of Complex Power Systems, EONERC\n");
-		printf("   Steffen Vogel <stvogel@eonerc.rwth-aachen.de>\n");
+		printf(" Copyright 2015, Institute for Automation of Complex Power Systems, EONERC\n");
+		printf(" Steffen Vogel <StVogel@eonerc.rwth-aachen.de>\n");
+
 		exit(EXIT_FAILURE);
 	}
 
@@ -87,7 +89,7 @@ int main(int argc, char *argv[])
 	config_init(&config);
 	config_parse(argv[1], &config, &set, &nodes, NULL);
 	
-	node = node_lookup_name(argv[3], nodes);
+	node = node_lookup_name(argv[3], &nodes);
 	if (!node)
 		error("There's no node with the name '%s'", argv[3]);
 
@@ -122,9 +124,9 @@ int main(int argc, char *argv[])
 					error("Unknown option '-%c'.", optopt);
 				else
 					error("Unknown option character '\\x%x'.", optopt);
-				exit(1);
+				exit(EXIT_FAILURE);
 			default:
-				abort ();
+				abort();
 		}
 		
 		continue;
@@ -155,7 +157,7 @@ void test_rtt() {
 	double avg = 0;
 
 	struct hist histogram;
-	hist_init(&histogram, low, high, res);
+	hist_create(&histogram, low, high, res);
 
 #if 1	/* Print header */
 	fprintf(stdout, "%17s", "timestamp");
@@ -201,5 +203,5 @@ void test_rtt() {
 	else
 		error("Invalid file descriptor: %u", fd);
 	
-	hist_free(&histogram);
+	hist_destroy(&histogram);
 }
diff --git a/server/src/utils.c b/server/src/utils.c
index cfdbf0486..d30dd2503 100644
--- a/server/src/utils.c
+++ b/server/src/utils.c
@@ -12,10 +12,11 @@
 #include <errno.h>
 #include <unistd.h>
 #include <netdb.h>
-#include <time.h>
 #include <math.h>
+#include <signal.h>
 
 #ifdef ENABLE_OPAL_ASYNC
+#define RTLAB
 #include <OpalPrint.h>
 #endif
 
@@ -23,20 +24,11 @@
 #include "cfg.h"
 #include "utils.h"
 
-/* This global variable contains the debug level for debug() and assert() macros */
-int _debug = V;
-int _indent = 0;
+pthread_t _mtid;
 
-struct timespec epoch;
-
-void outdent(int *old)
+void die()
 {
-	_indent = *old;
-}
-
-void epoch_reset()
-{
-	clock_gettime(CLOCK_REALTIME, &epoch);
+	pthread_kill(_mtid, SIGINT);
 }
 
 int strap(char *dest, size_t size, const char *fmt,  ...)
@@ -58,43 +50,6 @@ int vstrap(char *dest, size_t size, const char *fmt, va_list ap)
 	return vsnprintf(dest + len, size - len, fmt, ap);
 }
 
-void print(enum log_level lvl, const char *fmt, ...)
-{
-	struct timespec ts;
-	char buf[512] = "";
-
-	va_list ap;
-
-	/* Timestamp */
-	clock_gettime(CLOCK_REALTIME, &ts);
-	strap(buf, sizeof(buf), "%8.3f ", timespec_delta(&epoch, &ts));
-
-	/* Severity */
-	switch (lvl) {
-		case DEBUG: strap(buf, sizeof(buf), BLD("%-5s "), GRY("Debug")); break;
-		case INFO:  strap(buf, sizeof(buf), BLD("%-5s "),     "     " ); break;
-		case WARN:  strap(buf, sizeof(buf), BLD("%-5s "), YEL(" Warn")); break;
-		case ERROR: strap(buf, sizeof(buf), BLD("%-5s "), RED("Error")); break;
-	}
-
-	/* Indention */
-	for (int i = 0; i < _indent-1; i++)
-		strap(buf, sizeof(buf), GFX("\x78") " ");
-	strap(buf, sizeof(buf), GFX("\x74") " ");
-
-	/* Format String */
-	va_start(ap, fmt);
-	vstrap(buf, sizeof(buf), fmt, ap);
-	va_end(ap);
-	
-	/* Output */
-#ifdef ENABLE_OPAL_ASYNC
-	OpalPrint("%s\n", buf);
-#else
-	fprintf(stderr, "%s\n", buf);
-#endif
-}
-
 cpu_set_t to_cpu_set(int set)
 {
 	cpu_set_t cset;