Queue Holdtime Algorithm

david551 · March 22, 2022, 3:54pm

It’s an exponential average of the hold times for calls that have been answered. It is only really valid in the steady state. I’m not sure how it handles abandoned calls.

0.25*latest actual hold time + 0.75 * previous average, except the whole hold time is used for the first call.

github.com

asterisk/asterisk/blob/master/apps/app_queue.c#L4328

      
        
            	if (!res) {
            		if (ringing) {
            			ast_indicate(qe->chan, AST_CONTROL_RINGING);
            		} else {
            			ast_moh_start(qe->chan, qe->moh, NULL);
            		}
            	}
            	return res;
            }
            
            
static void recalc_holdtime(struct queue_ent *qe, int newholdtime)
            {
            	int oldvalue;
            
            
	/* Calculate holdtime using an exponential average */
            	/* Thanks to SRT for this contribution */
            	/* 2^2 (4) is the filter coefficient; a higher exponent would give old entries more weight */
            
            
	ao2_lock(qe->parent);
            	if ((qe->parent->callscompleted + qe->parent->callsabandoned) == 0) {
            		qe->parent->holdtime = newholdtime;