Bridged mode conection to the DSL modem

Hello all,

I m very new to Linux.... I having a problem solving a network issue....
I have connected a DSL modem to Eth0 of the RHEL 6.4 system.... The DSL modem is configured to work in BRidged mode....
I assigned the WAN IP address to the eth0 XXX.XXX.XXX.XXX and subnet mask 255.255.252.0 and gatway...
The problem is connection drops frequently ..... If i ping my ISP gateway it works for few minutes and after there is no response ....
Can you please help me out guys .....

Regards,
Karthik P