Hi Friends, i'm using mod_nibblebill for billing on FS, i bundled event processing fucntions when status change, e.g. /* on_routing */ check_billing_before_routing, and * on_hangup */ process_hangup, as below, however, i found it excuted the processing function on both A-leg and B-leg, what i want is that either only A-leg or only B-leg (i can select by coding), how can i realize it? P.S. is it possible that i identify the Legs (A or B) inside the processing function (e.g. check_billing_before_routing,) by intput parameter *sessionsession? source codes as below, switch_state_handler_table_t nibble_state_handler = { /* on_init */ NULL, /* on_routing */ check_billing_before_routing, /* Need to add a check here for anything in their account before routing */ /* on_execute */ sched_billing, /* Turn on heartbeat for this session and do an initial account check */ /* on_hangup */ process_hangup, /* On hangup - most important place to go bill */ /* on_exch_media */ NULL, /* on_soft_exec */ NULL, /* on_consume_med */ NULL, /* on_hibernate */ NULL, /* on_reset */ NULL, /* on_park */ NULL, /* on_reporting */ NULL, /* on_destroy */ NULL }; static switch_status_t check_billing_before_routing(switch_core_session_t *session) { //is it possible to identify the legs (A or B) here? ... } static switch_status_t process_hangup(switch_core_session_t *session) { ... } BR, Charles