extern bool send_del_subnet(struct connection_t *, const struct subnet_t *);
extern bool send_add_edge(struct connection_t *, const struct edge_t *);
extern bool send_del_edge(struct connection_t *, const struct edge_t *);
extern bool send_del_subnet(struct connection_t *, const struct subnet_t *);
extern bool send_add_edge(struct connection_t *, const struct edge_t *);
extern bool send_del_edge(struct connection_t *, const struct edge_t *);