dear sir
we have steel industry head office located at kolkata and above 20 branches all over india
we WANT to implement online erp software. but in some locations we dont have internet
connection. In how many ways we can implement it. How to implement online erp software without internet. It should be cost effective also. please suggest us best erp software.
can we use the methods like VPN, satellete internet or intranet or any similer best method?
thank u
Good day.

Dear venkat2014, you are asking a very technical question. If erp software requires network connection (not internet necessarily) you are obliged to obtain at least a phone line to be able to communicate through modems.
You are asking for a "RESEARCH operation" from our side, and this is not fair.

Small answers though: vpn - you need an internet connection or a network connection available. Satellite internet - it could be a good option (compare the prices of internet satellite connection with the prices to obtain a wireless or wired connection to the sites without wan network connection - and I mean implementation, monthly fees and maintenance).
Intranet - how big are those unlinked sites? Are there tens or hundreds of computers? What is the work volume at those sites? How much those sites affect the enterprise general volume of work, the general volume of changes? What do you mean by intranet? (If you mean a "part of the great company network - you need wan access to the rest of the network).

Your DEMAND is so general, so big and not refined.
We can help you with an opinion, with help to a small problem. Don't ask us to propose a plan for your company. It is much work, it is not for free, I don't want to work for no money. I can advice, I can give a very small advice for free, yes. But more than that...

My small advice: estimate the situation. You don't know how? Search a company that knows (ussually an ISP has people with knowledge about CONNECTING such far sites, but they are not necessarily the only option).

(Your demand seems to be a homework to me, I just hope that I misunderstand you. "thank u"? )