SDNP

To assist in the establishment of the SDN, UNDP has provided Bangladesh Institute of Development Studies (BIDS) with a starter kit comprising of computer hardware and software, key databases management and training tools, decision support tools, and other resources to meet individual need and ensure long-term compatibility with SDNs operating in other developing countries.

SDNP is successfully imminent to the Network development programme in Bangladesh through some pilot phases at this stage.

In First phase (Pilot) SDNP established local information centers, recruit professional, linkages to sources of technical expertise, provides them training and established target.

In Second phase SDNP organized the information center, acquire the equipments for nodal and remote stations and established the network. In this phase SDNP arranged various workshop, seminar, tours, initiate the training and support services.

Here are some very brief descriptions:

Experiment with SCPC (Single Channel Per Carrier) satellite equipment for central node. Testing with radio Equipments like Bi-directional Amplifiers, GSM Modem and SIMM-12 sets for strategic locations, Setup Access Server at central node for dialup connectivity to the remote users, etc.

In this phase three servers have connected at the central node. One NT server and two Linux base servers. NT server has been supporting more than 150 in-house LAN users as a file server. One tape drive is connected with the NT server, which is taking backup at every 24 hours. Linux servers are acting as primary and secondary servers providing services as mail server, ftp server, web server and database server.

In this phase SDNP successfully completed Mymensingh regional node while BAPTC link at Saver, LGED link at Agoargoan, Comfort diagnostics at Green road at Dhaka. Khamar-bari at Farm gate, BCS Academy at Shahbag, and IUCN at Banani Dhaka are under waiting to be connected to SDNBD Server.

At this moment SDNP is implementing several pipeline pilots as per recommendation of the Evolution mission, Pilot-1 related to development of a MDG portal in Bangla, Pilot -2 relates to establishment of multipurpose community centers along the costal belt of Bangladesh. Pilot-3 SDNP is assisting local ISP (Internet Service Provider) in routing domestic emails inside the country by establishing an internet Exchange. A few other pilots are at hand.

Pilot Phase:

The Primary server
Server Model: Compaq Proliant ML530

It was planned that this server will perform the task of Database server along with other primary jobs. But due to the fact that the main task of SDNP is to maintain a robust database and the database server will have to process numerous queries and tasks, a separate server has been dedicated as Database Server. Now the prime task of the Primary server is to authenticate the PPP dial-in users and act as Primary Domain Name System (DNS) server. In addition, it is also configured for World Wide Web server and newsgroup server (which will be served by the secondary server) so that in case of failure of the secondary server, it can resume those services to the users without interruptions.

The Secondary Server
Server Model: Compaq Proliant ML530

The Secondary server provides WWW (World Wide Web) service, FTP (File Transfer Protocol) service, News Group service. This secondary server does perform as Secondary DNS server as well. But this server has the similar setup as of the main server. Again this strategy was taken to keep the internet services as much uninterrupted as possible. Whenever it will be detected that the primary server has failed to respond it will start acting as primary server till the primary server is restored back to its previous working level. The data backup device is connected to this server for backing up important data periodically.

The Domain Controller
Server Model: Compaq Proliant ML530

The purpose of this server is to authenticate the LAN users. LAN users keep their important data and share those data here. So it operates as a file server. Another purpose of this server is to act as a print server.

This Server is powered by Windows 2000 Advanced Sever. All applications are run into it, including SDNP designed customized software.

A separate server is maintained to keep the valuable data in it. Linux was selected to be the OS of this server. For database Oracle 9i has been selected.

Other Major Hardware
The other major hardware is the Terminal server (TS2000), the Modem pool and the Local Area Network (LAN) Switch. The details are provided below.

Terminal server
A Terminal server acts as an answering machine for the users connecting over phone lines using modems. Since most of the users connect over phone lines, a Terminal server is required. Without the help of the Terminal Server it is not possible to provide a good service. It provides very reliable connectivity both in terms of speed and reliability. All the ports of the Terminal server will be configured for dial-in. The users will get connected to the Terminal server from outside the BIDS by dial-up method and the Terminal server will connect them to the whole network. Now for the pop dial in users modems are connected using a multiport serial card.

Terminal Server:
Model: TS2000
Manufacturer: Cyclades
Number of Ports:
Port Type: 32 RS-232 DTE on RJ-45, 921 Kbps

The Modem pool is nothing but a group of modems in a single box or chassis with better management options and utility. The Modems in the modem pool will be connected to the Terminal server. The phone lines that are engaged for dial in users will be connected to each of the modems in this modem pool.

LAN Switch
For a UTP cable based Ethernet network, a LAN Hub or a Switch is a must. For a large LAN like we do have only a switch can provide the most reliable and high speed connection because it provides much better bandwidth utilization over a Hub by reducing collision and caching the hardware addresses of the network adapters in its internal database. Currently we are using a 24 port switch. It is capable to provide VLAN service and have the options to install a optical module into it.

Switch Model: Cisco 2900 XL Series
Switch Model: 3Com
ADSL Concentrator-01
Brand/Model: IES-1000
IES-1000 enclosure with two slide-in slots for DSL modules, DC power input
Dimensions 440(L) x 320(D) x 44.5(H) mm
IES-1000 enclosure with two slide-in slots for DSL modules, AC power input
8-port Annex A ADSL line card (over POTS) with splitters built-in

The Operating System (OS) and the various server software used for the project has to be highly reliable, stable and well performed. That is why Linux has been selected as the Operating System for the servers. All other various server software that are required are available under Linux, a Unix like platform. The added advantage of Linux is that it is completely free of cost. The other SDN projects are also using Linux for their servers all around the world. Using Linux will give the flexibility of configuring the system better suited to the SDNP targets.

The Network protocol selected is TCP/IP (Transmission Control Protocol/Internet Protocol ). TCP/IP is the standard protocol for the Internet service. It is also the native network protocol for the selected operating system - Linux. TCP/P gave us the option of connecting to the Internet and exchanging information without any major modification to the setup.

The servers (Primary, Secondary server and the Terminal Server) are connected to the Switch, thus forming the server LAN. The main Hubs at each floor of the Local Area Network consisting the workstations are connected directly to the ports of the Switch. This design gave us the less collision in the LAN.

Both the primary and the secondary servers are running under Linux. To make the setup robust, both servers are configured to run all common services. The domain controller was setup under Windows NT to ease the life. Maintaining the LAN users with NT is much simpler than with other OS.

When someone will try to log in over phone lines, the Terminal server will have to verify that the person is indeed a valid user with appropriate access. The Terminal server does this by contacting the authentication server. The primary server holds all the user accounts and passwords. Therefore, the authentication service is running on the primary server. The authentication service for dial-in is the standard Remote Authentication Dial In User Service (RADIUS). The primary server runs the RADIUS service. The secondary server keeps a duplicated copy of the user database in case it has to serve as the Authentication server.

Sendmail is used as our mail server software. It is just a Mail Transfer Agent (MTA). All Linux distribution comes with the Sendmail software. However, Sendmail only acts as the transport agent. If a user wants to send or receive his/her mail he/she must use different service called MUA (Mail User Agent). The standard protocols for this purpose are POP3 or IMAP. POP3 is most popular. However IMAP is getting more popular. Both of these services will be running on the primary server, since the user accounts are going to be on that. The Secondary Server also has these services configured.

In the network world based on TCP/IP, each computer (either a user or a server) is identified by a numeric address. This numeric address is known as the IP Address. But for human usability and convenience, all the machines are given a name as well. The name to IP address mapping is known as the Domain Name System (DNS). Both the Primary and the Secondary servers run the DNS service. The DNS server software used here is Berkeley Internet Name Domain (BIND). BIND itself has the feature of running in primary and secondary mode. Secondary DNS server is maintained for redundancy. If the Primary DNS server fails to respond the Secondary server takes over.

A gateway server is the link between two networks (such as between a local network site and the Internet). Each Internet site has a gateway server. A communications server, which provides access between networks, which use different access protocols.

Print Server

A computer and/or software to provide users or a network with access to a central printer. The printer server acts as a buffer, holding the information to be printed out in memory until the printer is free. It is possible to program the printer server to print jobs in the order they arrive or to give priority to particular users who, in effect, jump the queue. The advantages of a printer server include maximum exploitation of expensive resources like laser printers and not having to retry if the printer is initially busy.

The purpose of this server is to serve the web pages when someone starts browsing this site. HTTP (Hyper Text Transfer Protocol) is the standard protocol for this purpose. Apache is the most popular web server and has the most flexibility in operation. The Secondary Server also runs this service. But the Primary Server is configured for it mainly.

A File Transfer Protocol (FTP) server acts as a server that has many files (could be information, could be programs) which the user can transfer (known as download) to his or her computer. The Secondary server will provide this service. That means, all the downloadable files will also reside on the Secondary server. The primary server will also have this service configured.

A Newsgroup is a discussion group, where any user can post an article or respond to an article posted by someone else. The Newsgroup server going to be used is Internet News (INN). INN is the most used Newsgroup server software on the Internet and comes with Linux as well.

The PP in Operation When a user needs some information and accesses the servers over the phone line, this is what happens:

For LAN users they also have to prove their authenticity. The domain controller does check this.

During the normal operation of the servers, the major maintenance job is to take backup of the servers on a regular basis. We have selected to use DLT4000 tape drives, which can hold up to 2OGB of uncompressed (40GB compressed) data. Backup is taken every other day to a new tape. The tape is received after 30 days, which means there are going to be 15 tapes, each holding the backup of the servers for the past 30 days at an interval of 2 days.

The backup device is connected to the secondary server. The Primary server is backed up over the network and the secondary server is backed up directly.

UPS
Two worlds standard UPSs (Uninterruptible Power Supply) are constantly monitoring the power lever and backing up the equipments.

Generator
A self-starting Generator is engaged for backing up the power for as long as 6 hours in case of power failure for long time. After the power failure occurrence the ATS (Auto Transfer Switch) kick starts the generator within 4 seconds. It is extremely reliable design for power backup.

Data Backup System
Manufacturer: Compaq
Capacity: 20/40Gbyte
Model: Compaq 20/40 GB DLT

Function of the server: LAN users in BIDS and SDNP authenticate themselves through this server. This server backs up the important data to a backup media. All users share the software, Library information and update virus information from it.

This server also acts as a print server. Print server can control all user printing.

Activities of this server: This is the primary DNS server. This mail server handles all the email accounts. Our domain is ‘sdnbd.org’. Users can send and receive their mails either from LAN or by dialing into our servers. We have 24 hours dialup connectivity to BOL. We also use this server as proxy server for LAN stuff.

FTP server: This server we use as a FTP server. We upload important software (Shareware) in FTP server and latest virus information.

This is the secondary DNS server. This is proxy server as well. This server authenticates all dial-in users when they dial into it. Radius is used for authentication and maintains the billing information. After authentication they can send mails and do browsing. Proxy server has one 16-port Multi I/O card and 13 modems connected with telephone lines for dial up users.

This server is connected to the external world through a Radio Link with Main POP (point of premises). This server also acts as a router. At present the link speed is 10 Mbps full duplex.

Activities of the server: This server has four SCSI Hard Disk Drives. We configured it as a database server for web hosting and as a secondary proxy server. This database server is powered by Oracle. Online data can be accessed.

A separate server is maintaining the master database. The dynamically distributed databases are located in different regional nodes at different geographically distributed locations.