Pune - Frequent disconnection

Since a last few days, I am facing this problem - I am able to dial into dataone(i haven't kept it as always ON connection), everything works perfectly for some time, but after random time, the sites just stop showing up! It gets stuck at something like 'waiting for timesofindia.com'.. i disconnect.. and dial in again.. gets connected perfectly, but still sites don't show up!Then I switch the modem off (dsl2640T) and turn in on again. Now the connection starts working fine.Guys if there is any input, please do tell me. Its hugely frustrating and during these crucial times when i need to really concentrate on my studies on the internet, I am facing this annoying problem !Help will be really appreciated.Thanks.

Try opendns 208.67.220.220 and/or googledns 8.8.8.8
Change to PPPoE mode .
( Uncheck "bridged" box in wan page. enter userid/pw in router page)
Change mod mode to(for a stable connection) GDMT if on adsl2+
Download manual as, this is a discontinued model.

{manual}http://207.150.194.182/resources/installation_guide/DSL-2640T_B3_QIG_v100.pdf
qig:http://207.150.194.182/resources/installation_guide/DSL-2640T_B3_QIG_v100.pdf

hey thanks a lot for the advice.. I will see if I face any random disconnection now and report back.. Just a query: i changed preferred dns server and alternate dns server... that was what i had to change right? Or was it primary dns server and secondary dns server in DHCP?also.. when i switch the router off and on again.. the setting is gone 🙁 (alternate and preferred dns setting) .. have to change it every time i guess..

Thanks essbebe! Seems like the problem was solved after changing to google DNS!! Although it did reoccur only once (in like last 8-10 days) but I will ignore it!