The Best Tandem Switch

Hi guys,

which is the most intelligent and powerful, carrier class tandem switch with the capability of automatic rerouting functions, fraud detection and call blocking, congestion and failure detections. So far I noticed that the most popular were the ESWD (Siemens), DMS-GPS/500(nortel), S12(Alcatel) but it seems that all these products are discontinoud. I am wondering which tandem switches have replaced them and I didn’t hear or read any, did they switched to VOIP in tandem switching or something else. I read that BT has upgraded its class 5 switches to NGN , a project they dubbed as 21CN, but I am not sure if the tandam includes? any ideas please because I am tired of poor capable tandem switches
Thanks