PDP AUTHETICATION FAILURE FOR IPAD for idea celluar network in andhra pradesh in India
I see you're having cellular network troubles. I found this article and it sounds like it would help with what you are describing:
iPad (Wi-Fi + Cellular Models): Troubleshooting a cellular data connection
Step 4 states "Check for a carrier settings update." and links to "iOS: Updating your carrier settings" (http://support.apple.com/kb/HT1970), which I would also suggest trying.
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