diff --git a/dist/tools/zep_dispatch/.gitignore b/dist/tools/zep_dispatch/.gitignore
index 0a293e49d7..3c13b01d75 100644
--- a/dist/tools/zep_dispatch/.gitignore
+++ b/dist/tools/zep_dispatch/.gitignore
@@ -1,2 +1,3 @@
 *.gv
 *.pdf
+*.svg
diff --git a/dist/tools/zep_dispatch/Makefile b/dist/tools/zep_dispatch/Makefile
index 9e4ffed41f..95f5a3fef3 100644
--- a/dist/tools/zep_dispatch/Makefile
+++ b/dist/tools/zep_dispatch/Makefile
@@ -2,8 +2,9 @@ CFLAGS ?= -g -O3 -Wall -Wextra
 CFLAGS += $(RIOT_INCLUDE)
 CFLAGS += -DNDEBUG # avoid assert re-definition
 
-BINARY := bin/zep_dispatch
-all: bin $(BINARY)
+DISPATCH := bin/zep_dispatch
+TOPOGEN  := bin/topogen
+all: $(DISPATCH) $(TOPOGEN)
 
 bin:
 	mkdir bin
@@ -11,26 +12,32 @@ bin:
 RIOTBASE := ../../..
 
 ZEP_PORT_BASE ?= 17754
-TOPOLOGY      ?= example.topo
-GV_OUT        ?= example.gv
+TOPOLOGY      ?= network.topo
+GV_OUT        ?= $(TOPOLOGY).gv
 
 RIOT_INCLUDE += -I$(RIOTBASE)/core/include
 RIOT_INCLUDE += -I$(RIOTBASE)/cpu/native/include
 RIOT_INCLUDE += -I$(RIOTBASE)/drivers/include
 RIOT_INCLUDE += -I$(RIOTBASE)/sys/include
 
-SRCS := $(wildcard *.c)
+SRCS := main.c topology.c zep_parser.c
 SRCS += $(RIOTBASE)/sys/net/link_layer/ieee802154/ieee802154.c
 
-$(BINARY): $(SRCS)
+$(DISPATCH): $(SRCS) bin
 	$(CC) $(CFLAGS) $(CFLAGS_EXTRA) $(SRCS) -o $@
 
+$(TOPOGEN): topogen.c bin
+	$(CC) $(CFLAGS) $< -o $@ -lm
+
 .PHONY: clean run graph help
 clean:
-	rm -f $(BINARY)
+	rm -fr bin
 
-run: $(BINARY)
-	$(BINARY) -t $(TOPOLOGY) -g $(GV_OUT) ::1 $(ZEP_PORT_BASE)
+run: $(DISPATCH) $(TOPOLOGY)
+	$(DISPATCH) -t $(TOPOLOGY) -g $(GV_OUT) ::1 $(ZEP_PORT_BASE)
+
+$(TOPOLOGY): $(TOPOGEN)
+	./topogen.sh $(TOPOLOGY)
 
 graph:
 	killall -USR1 zep_dispatch
diff --git a/dist/tools/zep_dispatch/topogen.c b/dist/tools/zep_dispatch/topogen.c
new file mode 100644
index 0000000000..bfe8647eb5
--- /dev/null
+++ b/dist/tools/zep_dispatch/topogen.c
@@ -0,0 +1,242 @@
+/*
+ * Copyright (C) 2021 Benjamin Valentin
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License v2. See the file LICENSE for more details.
+ */
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <time.h>
+#include <math.h>
+#include <unistd.h>
+
+struct node {
+    char name[8];
+    int x;
+    int y;
+    unsigned r;
+    bool rx_from_root;
+    bool tx_to_root;
+};
+
+struct world {
+    unsigned w;
+    unsigned h;
+    unsigned num_nodes;
+    struct node *nodes;
+};
+
+static unsigned random_range(unsigned lower, unsigned upper)
+{
+    unsigned range = upper - lower + 1;
+    return lower + rand() % range;
+}
+
+static struct node *node_generate(struct node *n, const struct world *w,
+                                  unsigned range)
+{
+    n->x = random_range(0, w->w);
+    n->y = random_range(0, w->h);
+    n->r = range;
+    return n;
+}
+
+static double node_distance(const struct node *a, const struct node *b)
+{
+    return sqrt(pow(a->x - b->x, 2) + pow(a->y - b->y, 2));
+}
+
+static double node_distance_weight(const struct node *a, const struct node *b)
+{
+    double w = 1 - node_distance(a, b) / a->r;
+
+    if (w < 0) {
+        return 0;
+    }
+    return w;
+}
+
+static void node_name(struct node *n, unsigned idx)
+{
+    char *s = n->name;
+    const char *end = s + sizeof(n->name) - 1;
+
+    do {
+        uint8_t rem = idx % 26;
+        *s++ = 'A' + rem;
+        idx -= rem;
+    } while (idx && s != end);
+    *s = 0;
+}
+
+static void world_gen(struct world *w, unsigned num_nodes,
+                      unsigned width, unsigned height,
+                      unsigned range, unsigned var)
+{
+    w->w = width;
+    w->h = height;
+    w->num_nodes = num_nodes;
+    w->nodes = calloc(num_nodes, sizeof(*w->nodes));
+
+    for (unsigned i = 0; i < num_nodes; ++i) {
+        node_generate(&w->nodes[i], w, random_range(range - var, range + var));
+        node_name(&w->nodes[i], i);
+    }
+}
+
+static unsigned _color(const struct node *n, unsigned base)
+{
+    if (n->rx_from_root && n->tx_to_root) {
+        return base;
+    } else if (n->rx_from_root) {
+        return base / 2;
+    } else if (n->tx_to_root) {
+        return base / 3;
+    }
+
+    return 0;
+}
+
+static void _print_nodes(struct node *nodes, unsigned num, unsigned color)
+{
+    for (unsigned i = 0; i < num; ++i) {
+        printf("# %s\t%d\t%d\t%u\t0x%x\n", nodes[i].name,
+                                           nodes[i].x, nodes[i].y,
+                                           nodes[i].r, _color(&nodes[i], color));
+    }
+}
+
+/* To visualize the network we color the nodes based on whether they have
+ * a (bi-directional) connection to the root node via some other node(s).
+ */
+static void _calc_connections(struct node *nodes, unsigned num)
+{
+    bool changes = true;
+    nodes->rx_from_root = true;
+    nodes->tx_to_root = true;
+
+    /* super basic algorithm - just loop unti there are no more changes
+     * in the node's connection states. */
+    while (changes) {
+        changes = false;
+
+        for (unsigned i = 0; i < num; ++i) {
+            const struct node *n = &nodes[i];
+
+            for (unsigned j = 0; j < num; ++j) {
+                struct node *m = &nodes[j];
+
+                /* node is already fully connected */
+                if (m->rx_from_root && m->tx_to_root) {
+                    continue;
+                }
+
+                /* m can receive from n and n can receive from root */
+                if (node_distance_weight(n, m) > 0) {
+                    if (!m->rx_from_root && n->rx_from_root) {
+                        m->rx_from_root = true;
+                        changes = true;
+                    }
+                }
+
+                /* m can send to n and n can send to root */
+                if (node_distance_weight(m, n) > 0) {
+                    if (!m->tx_to_root && n->tx_to_root) {
+                        m->tx_to_root = true;
+                        changes = true;
+                    }
+                }
+            }
+        }
+    }
+}
+
+static void _print_distance(struct node *nodes, unsigned num, bool recursive)
+{
+    struct node *start = nodes;
+
+    for (unsigned i = 1; i < num; ++i) {
+        struct node *n = &nodes[i];
+
+        double to_node   = node_distance_weight(start, n);
+        double from_node = node_distance_weight(n, start);
+
+        if (to_node > 0 || from_node > 0) {
+            printf("%s\t%s\t%.2f\t%.2f\n", start->name, n->name, to_node, from_node);
+        }
+
+        if (recursive) {
+            _print_distance(n, num - i, false);
+        }
+    }
+}
+
+static void _print_help(const char *name)
+{
+    puts("Generate a number of nodes that are randomly placed in a rectangular area");
+    printf("usage: %s [-s <seed>]"
+                    " [-w <width>]"
+                    " [-h <height>]"
+                    " [-r <range>]"
+                    " [-v <variance of range>]"
+                    " [-n <nodes>]"
+                    "\n", name);
+}
+
+int main(int argc, char** argv)
+{
+    const char *progname = argv[0];
+
+    unsigned width  = 100;
+    unsigned height = 100;
+    unsigned seed   = time(NULL);
+    unsigned range  = 25;
+    unsigned var    = 0;
+    unsigned num    = 10;
+    char c;
+
+    while ((c = getopt(argc, argv, "s:w:h:r:v:n:")) != -1) {
+        switch (c) {
+        case 's':
+            seed = atoi(optarg);
+            break;
+        case 'w':
+            width = atoi(optarg);
+            break;
+        case 'h':
+            height = atoi(optarg);
+            break;
+        case 'r':
+            range = atoi(optarg);
+            break;
+        case 'v':
+            var = atoi(optarg);
+            break;
+        case 'n':
+            num = atoi(optarg);
+            break;
+        default:
+            _print_help(progname);
+            exit(1);
+        }
+    }
+
+    srand(seed);
+
+    struct world w;
+    world_gen(&w, num, width, height, range, var);
+
+    printf("# seed = %u\n", seed);
+    puts("# Connections");
+    _print_distance(w.nodes, w.num_nodes, true);
+    puts("");
+    puts("");
+    puts("# Node\tX\tY\trange\tcolor");
+    _calc_connections(w.nodes, w.num_nodes);
+    _print_nodes(w.nodes, w.num_nodes, rand());
+
+    return 0;
+}
diff --git a/dist/tools/zep_dispatch/topogen.sh b/dist/tools/zep_dispatch/topogen.sh
new file mode 100755
index 0000000000..733bfbdc2e
--- /dev/null
+++ b/dist/tools/zep_dispatch/topogen.sh
@@ -0,0 +1,42 @@
+#!/bin/bash
+
+if [ -z "$1" ]; then
+    FILE=out.top
+else
+    FILE="$1"
+fi
+
+if tput colors &> /dev/null && [ "$(tput colors)" -ge 8 ]; then
+    COK="\e[1;32m"
+    CWARN="\e[1;33m"
+    CRESET="\e[0m"
+else
+    COK=
+    CWARN=
+    CRESET=
+fi
+
+WIDTH=100
+HEIGHT=100
+RANGE=30
+VARIANCE=15
+NUM=10
+
+echo "writing to $FILE"
+
+./bin/topogen -w $WIDTH -h $HEIGHT -r $RANGE -v $VARIANCE -n $NUM > "$FILE"
+
+if ! command -v gnuplot > /dev/null; then
+    printf "${CWARN}%s${CRESET}\n" "gnuplot not installed"
+    exit 0
+fi
+
+printf "${COK}%s${CRESET}\n" "rendering to ${FILE}.svg"
+gnuplot -e "set xrange [0:$WIDTH]" 			\
+	-e "set yrange [0:$HEIGHT]" 			\
+	-e "set terminal svg size $(( WIDTH * 8 )), $(( HEIGHT * 8 ))" \
+	-e "set output '$FILE.svg'"			\
+	-e "set datafile commentschars '!'"		\
+	-e "set style fill transparent solid 0.25"	\
+	-e "plot '$FILE' index 1 using 3:4:(\$5*2):(\$5*2):6 with ellipses lc rgb var notitle,	\
+	         '$FILE' index 1 using 3:4:2 with labels point pt 2 offset char 0.5,0.5 notitle"