we have 8 branch offices in my city and all of us work on same application, so we want to connect all the branches with WAN(private network) and use this application by keeping a server at main office and user the server from all other branches. The complete distance between all the branches on a total was around 4KM can any one help me out and suggest the best to config them and at a low cost.
i have the fallowing questions running in my mind
1. how much it cost for cabling 4km.
2. whom to contact to have cabling
3. who will provide cabling
4. will my network be secure
Best config and low cost in this case are mutually exclusive.
The best config would be to lease dedicated lines from your local telco provider. Pricing can be very high, but speed and reliability will be the very best. You might want to contact a local network services company to provide recommendations and consulting services.
The cheapest config would be to just get consumer Internet connections at each site and use a site-to-site VPN to connect all the offices to a single "central" office. There are lots of ways to do this, but it could be done for a few hundred dollars in equipment and probably $300-$400 per month in ISP charges. It would be slower and less reliable, but much cheaper - assuming down time doesn't cost you too much money.
Both solutions can be completely secure.
Running your own cable, or having someone do it for you is probably not possible.