Setting Beetel BX220 (Modem provided with Airtel) in Always On Mode
Though of documenting it "Har baar bhool jata hu"

Configure Machine IP to some in 192.168.1._ subnet as modems default ip is 192.168.1.1.

IP: 192.168.1.3
Subnet: 255.255.255.0
Default Gateway: 192.168.1.1 (Modem's IP)

Follow following steps:
1 ) Open ADSL's Setup page http://192.168.1.1
Username:admin
Password:password
2 ) At the left side click on "WAN"
3 ) Remove all rows.
4 ) Add new entry VPI & VCI 1 & 32 respectively.
5 ) In connection type select PPPOE and Encapsulation type is LLC/SNAP - BRIDGING
6 ) PPP username : 0102xxxxxxxxxx@touchtelindia.net PPP Password : xxxx
PPPOE Service Name : Airtel Authentication Method : PAP
7 ) Again give next and Save
8 ) After Save the information select Reboot and click Save/Reboot button

After this setup Modem will get a IP from DHCP. We need to assign static IP to PC.
Follow following steps:

1 ) IP: 192.168.1.3 (Modems subnet)
2 ) Subnet: 255.255.255.0
3 ) Default Gateway: 192.168.1.1 (Modems IP)
4 ) DNS: 202.56.215.6 & 202.56.230.6

Woof!!! its done. Now you don't need to dial up from your PC.

Let me extend this to capture some configuration settings to NetGears WGR614 WiFi Modem so it connects smoothly to Beetel BX220.

Note: Select is shown with a (x)

1 ) http://192.168.1.1
Username:admin
Password:password
2 ) Goto Basic Settings
a ) Does Your Internet Connection Require A Login?
Yes
No (x)
b ) Internet IP Address
Get Dynamically From ISP
Use Static IP Address (x)
IP Address: 192.168.1.3
IP Subnet Mask: 255.255.255.0
Gateway IP Address: 192.168.1.1
c ) Domain Name Server (DNS) Address
Get Automatically From ISP
Use These DNS Servers (x)
Primary DNS: 202.56.215.6
Secondary DNS: 202.56.230.6

Default IP of Beetel ADSL modem & Netgear WiFi modem is same 192.168.1.1 and same is the default gateway so lets change Netgears IP address.
3 ) Goto LAN IP Setup
a ) LAN TCP/IP Setup
IP Address: 192.168.2.1
IP Subnet Mask: 255.255.255.0
b ) Use Router as DHCP Server (x)
Starting IP Address: 192.168.2.2
Ending IP Address: 192.168.2.51