IntroductionThe purpose of this network is to serve as a backbone for the legal database currently in development by Patrick and his team. Ten cantons need to be connected to the Ministry of Justice at Sarajevo. The main database server will sit at the Ministry of Justice, which will mirror of ALL the information available at each of the individual cantons.The first decision that needed to be made about the network was what kind of networking technologies should be used. This depends on how the database works. If all the cantons need to be able to talk to each other, we would essentially have a Metropolitan Area Network (MAN). This means that there would be a lot of network traffic flowing through all the data lines. This would require us to use LAN extenders along with CSU/DSUs (CSU/DSU's are essentially modems for leased lines). However, the problem with this solution is that high bandwidth solutions would be required. Patrick decided to set up the database so that the main server at Sarajevo will mirror all of the information contained at each individual canton. This means that each canton only needs to be able to exchange data with the main server, and not with any other canton. As far as network traffic goes, this is a much more efficient solution. WAN (Wide Area Network) technologies can be used to segment each canton into having its own "network". Each canton will then communicate with the main network at Sarajevo to upload its information, and to downlaod any information that has been requested.
56K Leased Lines (Schematics)The ideal solution for such a network would be to use 56K leased lines going from Sarajevo to each of the cantons. This solution is quite expensive.Equipment Required at EACH canton:
Equipment Required at the Ministry of Justice:
The Cisco 1600 series is a low-end range of routers. The 1601 is the one of the simplest routers you can buy. However, a 1602 router would serve as better as it has a built in CSU/DSU, eliminating the need for extra equipment. The router at the Ministry of Justice would need to be a high end router capable of handling 10 WAN connections (this is handled by setting up 10 virtual circuits, one for each canton). Note about routing: Routing can also be performed by an NT, Solaris or Linux server. All we would need to do is stick another network card into the server and set up the server to perform routing. This is quite easy and also very cheap. A network card for an NT server would only be around $20, and for a Sun system, maybe around $200. However, the problem here is that we'd need to interface the server with the CSU/DSU and I'm not sure what hardware is available to do this. If anyone knows, please contact me and let me know.
DSL (Schematics)DSL is a relatively new technology that works over the standard telephone network. Its main advantage is VERY high bandwidth. Upstream rates for ADSL can vary from 16-640Kbps depending on the down stream rate. Down stream rates range from 1.5Mbps to 6Mbps. This type of technology would make our network amazingly fast. 100s of times faster than a standard modem.Equipment Required at EACH canton:
Equipment Required at the Ministry of Justice:
This is a fast and very reliable solution. However, there are numerous problems with DSL, with cost being number one. Another problem is availability. Since its a new technology, it is hard to find. Also, in order for DSL to work, each canton would have to be located within a couple of miles from a telephone company's Central Office.
Dial-Up (Schematics)Dial-up modems can also serve as a solution, though we'd have to worry about telephone bills. The equipment and setup would be rather simple. The telephone network would serve as a backbone for the whole network.Equipment Required at EACH canton:
Equipment Required at the Ministry of Justice:
Terminal servers are essentially a pool of modems all in one box.
SatelliteFernando has come across some interesting satellite technologies for operation Kosavo which we could also use for networking the cantons. The equipment that's needed will be similar to the dial-up solution. The satellite technology works over the phone network. A modem is plugged into the client PC. The modem connects into the satellite transmitter, which transmits to the phone network. The client PC dials a phone number which connects it to a modem (or terminal server) connected to the server.Equipment Required at EACH canton:
Equipment Required at the Ministry of Justice:
I believe Fernando is in the process of writing up a report on the technologies he has discovered. Wireless (Schematics)I'm not exactly sure about the hardware requirements for wireless communication. I believe (but I'm not sure) that a wireless transmitter acts just like a CSU/DSU does for leased lines. If this is the case, then once again, we would need routers. There are numerous problems with wireless network though. They provide low bandwidth, they are more susceptible to interference, and cost a lot more than wired networks. I'm not sure about the hardware, but here's my best guess.Equipment Required at EACH canton:
Equipment Required at the Ministry of Justice:
I'm not sure if one wireless transmitter would work at Sarajevo to serve all 10 cantons. Other CommentsAlthough I mentioned five different technologies that we could utilize, in reality our network will probably use a mixture of all of them. Each canton might have its own "best way" it can be hooked up to the main Sarajevo site. Also, the sixth technology that was not discussed at all is simply to use the internet as a solution. However, Patrick informs me that there is a lack of ISPs in Bosnia, so this may be hard to do. If this is feasible at some cantons, all that's needed to work off the internet is a modem at each location. It is a cheap solution, but we also have to take into account phone and ISP service charges.
 |
