zte k2525 problem

GPRS modem disconnects after browsing two or the pages. even with ordinary dialup created and used, behavoiur remains the same. on using vodafone propriety software for this modem same problem appears. the connections disconnections after two or three pages. on doing a continuous ping the network stays without disconnection. but text messages can be sent without any hussle. can anyone help? anything from the GGSN to SSGN level configuration that needs to be change?