Rule SPD	(global relaxation option):
	SPD_cache.add (packet.S, packet.$H_c$);
	ce = SPD_cache.get (packet.D);
	if (ce != NULL) {
	packet.$H_b$ += (C == 0) ? 0: ce.SCount / C;
	if (packet.$H_c+ce.Hops>$ packet.$H_b+A$) {
	ce.SCount++;
	return SUCCEED;
	}
	}
	return FAIL;