Transformation of telecommunication Network Past Present Separated Network Partially Integrated Voice Data (Voice, Data, Wired, Wireless) Network Mobile Data Voice PSTN Internet ATM Switch IP Router z STM ATM IP C PDsN Ci IP Router Exchange MSC .MSC: Mobile Switching Center .ATM: Asynchronous Transport Mode . PDsn Packet Data Service Node IP: Internet Protocol STM: Synchronous Transport ModeTransformation of Telecommunication Network Transformation of Telecommunication Network Past Separated Network Separated Network (Voice, Data, Wired, Wireless) (Voice, Data, Wired, Wireless) Present Present Partially Integrated Voice & Data Partially Integrated Voice & Data Network Network Mobile Mobile N/W PSTN Data N/W MSC ATM Switch IP Router Switch Data Voice Exchange IP Router STM ATM IP MS C PDSN PSTN Internet •PDSN : Packet D ata Service N ode •STM : Synchronous Transport Mode •M SC : Mobile Switching Center •ATM : Asynchronous Transport Mode IP : Internet Protocol