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February 25, 1999


Penguins can fly too! The best things for ISPs come free. Srikant Sreenivasan roots for Linux, OSS and freeware. An Internet service provider is first a business. And no entrepreneur will ever attribute the success or failure of a venture to just one variable.

Email this story to a friend. From market and finance strategies, through technology to human resources, there is so much to be done. And done right.

But technology is going to be critical for the ISP gig in India. That is because government regulation is likely to keep the bandwidth retail price uniform for some time to come. Competition then will work around quality, packaging and lower cost of operation.

Luckily, the best technology to run an ISP is either free or in the open source domain. And that cuts costs like nothing else.

But are things ever that easy! The water's been muddied by systems and networking vendors who are working hard to catch the big catches.

Only time will name the winner.

But, for now, here is a tip: Linux is the way to go! And don't tell me I didn't warn you. This is doubly true for at least ISPs. After all, they are supposed to have sufficiently tech savvy staff.

This article presents Linux as a cost-effective and viable alternative to commercial software and the freeware status of Linux notwithstanding, Linux as the platform on its own merit.


Throughout this article, I am going to assume that all hardware and infrastructure is already available.

What you need to be an ISP?

Lots of patience. And...

  1. Dedicated connectivity to the Internet via a leased line, microwave connection, satellite, etc.
  2. Dialup telephone lines, preferably with a single hunt number.
  3. Leased line modems.
  4. Router.
  5. Terminal servers / serial boards.
  6. Modem racks.
  7. At least one server. Recommended three.
  8. The current stable distribution of Linux. Please note that this article focuses on RedHat Linux 5.2.
  9. Related software such as RADIUS / TACACS servers, billing systems, user management utilities, system and network management utilities, etc.
  10. Additional services such as freebies, dialler, start-up kit and, of course, tech support.

Well, now on to each of the above in detail:

1. Dedicated connectivity to the Internet via a leased line, microwave connection, satellite, etc

As of date, a prospective ISP can get bandwidth only from VSNL in India. VSNL offers several kinds of packages starting from 64 KBPS leased lines to 2 MBPS.

This can be availed via conventional leased line circuits through the Department of Telecommunications and via microwave.

Alternatively, bandwidth can be bought from foreign backbone providers via satellite. However, note that this option can be quite expensive.

A cost-effective approach will be to source a 2 MBPS 'downstream' bandwidth and a conventional 128 KBPS leased line for 'upstream' traffic.

This solution should suffice for most applications because the downstream traffic is several times more than the upstream traffic.

2. Dialup telephone lines, preferably with a single hunt number

Now this may take some doing because the telephone infrastructure in most cities is well below acceptable standards.

Also being in the ISP business, it makes lots of sense to be on the good side of the local telephone authorities.

Ask the telephone company for a single hunt line because this will make dialling easy for the subscriber.

Try to locate your network centre as close to the area telephone exchange, which should preferably be a digital exchange.

3. Leased line modems

Depending on the distance of your network centre from the telephone exchange, you will need to procure two or more leased line modems.

One modem will be installed at your network centre and the other will be located at VSNL's premises. The leased line from DoT will terminate at this modem.

4. Router

The leased line modem (or microwave / satellite indoor unit) will in turn terminate on a WAN port of your router.

In the router market, Cisco is usually acknowledged as the leader. There are several other prominent players too such as Bay Networks, 3Com, etc.

Find a router that meets your requirements. It must have at least one WAN port, one LAN port and one serial port.

5. Remote access servers / terminal servers / serial boards

RAS, terminal servers and serial boards, each have their merits and demerits.

Even if your budget were challenged, I would recommend the terminal server approach.

Serial boards are applicable only for very small ISP's with a maximum of around 16 telephone lines.

Serial boards fit into an ISA/PCI slot on your server. You can pick from a range of boards that may have from 4 to 16 ports each. Using the supplied cables, like the octopus cables, for instance, you can connect a dialup modem to each port.

Terminal servers would be the best choice for most ISPs. Terminal servers can provide dial-in access for a large number of users on standard telephone lines and ISDN BRI lines.

These come in several flavours from a 10-port version to a 40-port version per unit. And multiple units can be stacked.

Most terminal servers are compatible with RADIUS and or TACACS for user authentication.

6. Modem racks

Unless the terminal server that you buy has integrated modems, you will need to look at some modem rack solutions.

Hayes and Microtech, among others, have several models ranging from 8 modems per bank to 48 modems per bank. Many models are SNMP compliant for easy management.

A major consideration while choosing modems is that they should have exceptional dial-in performance. Also, be sure to test modems at your location as the actual performance depends on the area telephone exchange.

7. Servers

At a pinch, you will need three servers. One for each of the following functions:

  • Authentication and billing server
  • Web server And Domain Name Server
  • Mail server

The authentication server will run the RADIUS / TACACS daemon and the ACUA user management software.

In addition, all billing systems will be installed here. This server will also give you valuable MIS reports like:

  • Number of users for the day
  • Average login duration per user
  • Number of simultaneous logins by the same user

Apache 1.3.4 will do as the Web server for your site and for hosting your client's sites.

Apache powers over 55 per cent of the Internet today and is very robust and feature-rich. Major Internet sites using Apache include Yahoo and Hotmail.

You can either use 'sendmail' or 'qmail' as your mail server software.

Sendmail is the mail workhorse of the Internet, powering over 80 per cent of the mail on the Internet.

Qmail is relatively new but far easier to set up and maintain. In fact, Hotmail, the popular Web based free email provider, uses qmail as its mail server to handle more than 11 million users!

8. Linux

Well, at last we come to the glue behind the entire ISP set-up.

There are several Linux distributions around. Amongst the easier ones to install is the RedHat distribution.

The current release is RedHat Linux 5.2. The official distribution comes with manuals. Support in India is limited but that should not usually be a problem because help is easily available on the Internet.

Also, be sure to check out for local Linux support groups.


TACACS is the older standard and was originally developed by Cisco Systems.

RADIUS is the newer protocol and was developed by Livingston that is now a part of Lucent.

Daemons for both are freely available on the Net for Linux. These are usually in the source code form and will need to be compiled and configured.

Usually each router / terminal server will produce a separate log file. These may have to be merged and fed to your billing software.

The format of the log files is standard and writing simple billing software should be straightforward.

Installing user management software like ACUA will help in controlling access and giving flexible access plans to your users.

10. Miscellaneous

Staff: Technology support, sales.

Value added services like virtual office and corporate email.

Technology support and user ware like dialler, browser and TCP/IP stack.

Srikant Sreenivasan is the Linux and OSS enthusiast at Rediff. He was involved in setting up a complete Linux and OSS based infrastructure for India's first ISP, WMINet.


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