Add data structure definitions for Access Control Class ramping.

Change-Id: I0a5ac3a08f992f326435944f17e0a9171911afb0

1 files changed, 53 insertions, 0 deletions

diff --git a/include/osmocom/bsc/gsm_data_shared.h b/include/osmocom/bsc/gsm_data_shared.h
index e3e138957..aa532cec3 100644
--- a/include/osmocom/bsc/gsm_data_shared.h
+++ b/include/osmocom/bsc/gsm_data_shared.h
@@ -578,6 +578,56 @@ struct load_counter {
 	unsigned int used;
 };
 
+
+/*
+ * Access control class (ACC) ramping is used to slowly make the cell available to
+ * an increasing number of MS. This avoids overload at startup time in cases where
+ * a lot of MS would discover the new cell and try to connect to it all at once.
+ */
+
+enum bts_acc_ramp_step_size {
+	BTS_ACC_RAMP_STEP_SIZE_MIN = 1, /* allow at most 1 new ACC per ramp step */
+	BTS_ACC_RAMP_STEP_SIZE_DEFAULT = BTS_ACC_RAMP_STEP_SIZE_MIN,
+	BTS_ACC_RAMP_STEP_SIZE_MAX = 10, /* allow all ACC in one step (disables ramping) */
+};
+
+enum bts_acc_ramp_step_interval {
+	BTS_ACC_RAMP_STEP_INTERVAL_MIN = 1,		/* 1 second */
+	BTS_ACC_RAMP_STEP_INTERVAL_DEFAULT = 60,	/* 1 minute */
+	BTS_ACC_RAMP_STEP_INTERVAL_MAX = 300,		/* 5 minutes */
+};
+
+struct bts_acc_ramp {
+	/*
+	 * Bitmasks which keep track of access control classes that are currently
+	 * denied access to this BTS. These masks modulate bits from octets 2 and 3
+	 * of the RACH Control Parameters (see 3GPP 44.018 10.5.2.29).
+	 * While a bit in these masks is set, the corresponding ACC is barred.
+	 * Note that t2 contains bits for classes 11-15 which should always be allowed,
+	 * and a bit which denies emergency calls for all ACCs from 0-9 inclusive.
+	 * Ramping is only concerned with those bits which control access for ACCs 0-9.
+	 */
+	uint8_t barred_t2;
+	uint8_t barred_t3;
+
+	/*
+	 * This controls the maximum number of ACCs to allow per ramping step (1 - 10).
+	 * The compile-time default value is BTS_ACC_RAMP_STEP_SIZE_DEFAULT.
+	 * This value can be changed by VTY configuration.
+	 * A value of BTS_ACC_RAMP_STEP_SIZE_MAX effectively disables ramping.
+	 */
+	enum bts_acc_ramp_step_size step_size;
+
+	/*
+	 * Ramping step interval in seconds.
+	 * This value depends on the current BTS channel load average, unless
+	 * it has been overriden by VTY configuration.
+	 */
+	unsigned int step_interval_sec;
+	bool step_interval_is_fixed;
+	struct osmo_timer_list step_timer;
+};
+
 /* One BTS */
 struct gsm_bts {
 	/* list header in net->bts_list */
@@ -787,6 +837,9 @@ struct gsm_bts {
 	/* do we use static (user-defined) system information messages? (bitmask) */
 	uint32_t si_mode_static;
 
+	/* access control class ramping */
+	struct bts_acc_ramp acc_ramp;
+
 	/* exclude the BTS from the global RF Lock handling */
 	int excl_from_rf_lock;