Monday, November 4, 2002		Feature

Can the Internet go down?

The Internet is a modern-day electronic cockroach; it adapts and survives, says Roopinder Singh, as he examines how most users were not even aware of the biggest attack on the World Wide Web.

TO those of us in India who are usually disconnected from the Internet for one reason or the other, the answer to the question, "Can the Internet ever go down?" would be surprising: No. The proof of this came on October 21 when a powerful attack was launched on the Internet, and yet most of us were not even aware of it.

The Internet is the world’s largest distributed computer network and has been designed such that it has a high degree of redundancy and resilience. When two computers connect on the Internet, they can do so from a variety of routes and connections, and the system is designed in a way that if a part of it is not functioning for whatever reason, other parts take over.

Why Internet?

The Internet was designed by US defence experts with active help from various universities to be a network that could survive nuclear hits and still connect vital personnel. Over the years the civilian use of the Internet has eclipsed the military origins and it has become the world’s largest dispenser of information.

We are used to one or a couple of companies providing us with services like electricity and water. The Internet, on the other hand, is not controlled by any company, or even any government, not even the US Government that started it. It is an international matrix of lakhs of networks owned by tens of thousand of entities. There are said to be as many as 10,000 Internet service providers (ISPs) and they are the ones that provide access to the Internet to individuals and businesses.

How Internet works

Traffic on the Internet is through packets of data. Your data is first chopped into small, manageable packets. They go to your local ISP, which in turn sends them to a bigger network and so on, till they reach the destination, where they are seamlessly reassembled.

How do you get to a site on the Internet? Well, actually, you access the World Wide Web, which is a part of the Internet. Let us say that you want to go to the Website of The Tribune. You input the Web address (www.tribuneindia.com) in the browser window. This address is also called the universal resourse locator (URL). Now, actually The Tribune Website’s Internet address (IP number) is 64.14. 239.174.

Your service provider’s network has computers that have a list know as domain name service (DNS). This matches the name (www.tribuneindia.com) and supplies the IP number 64.14. 239.174. Once you have this information, you are well on the way to access the information you wanted.

The root

At the very basic level, there are 13 big name servers, called root servers, which direct queries to top-level domains. The attack on Monday briefly brought to knees nine out of these 13 servers and is considered one of the most powerful attacks on the Internet. We need to remember that the servers are place at different geographical locations all over the world and designed to operate independent of each other. The attack was severe, and it lasted an hour, but most of the Internet users did not even notice it.

The attack

At the basic level, this was a denial of service or smurf attack. Such attacks are typically launched after hackers take over thousands of computers of unprotected networks like those of universities and corporations, and use them to send unnecessary or junk data packets at a particular time to the selected targets, which tie themselves in knots in trying to answer meaningless queries. This attack was a large attack, though experts said it was not a particularly vicious one and the computers were temporarily overwhelmed, i.e., they were unreachable or debilitated by the traffic, though defensive measures by experts restored them soon. Network administrators do admit that the service was degraded during this time, though it did not break down.

The US Government has been aware of this problem and, in fact, President Bush’s top computer security adviser, Richard Clarke, has been warning for months of this very kind of an attack. Some computer experts contend that Monday’s attack was a close call, and in case one more computer had failed, e-mails and Web browsing for many people across the Internet would have been disrupted.

Theoretically, the Internet could function even if only one of the root servers is functioning, though this has never been tested. The two most serious outages concerning root servers occurred in August 2000 when four of the 13 root servers failed for a brief period because of a technical glitch and in July 1997 after experts transferred a garbled directory list to seven root servers. The problem was not corrected for four hours and traffic on much of the Internet ground to a halt.

Kinds of disruptions

Typically, the disruptions that we experience are different. When we normally say that the Internet is down, we refer to the connectivity between our computer and the Internet. A telephone dial-up connection is most commonly used for this purpose and in areas where it is unreliable, the Internet can’t be accessed.

Some lucky souls have cable connectivity that gives them much better access and near-broadband capabilities, but this is for a minority, the rich one, and even this is susceptible to disruptions or outages. In fact, all "last mile" delivery systems—modem dialup, ISDN, DSL, cable modem, wireless, leased line, etc.—are like approach ramps to the information superhighway. If one ramp is not accessible, you can get on the highway through another ramp.

Once you are on the superhighway, there is a vast network, with built-in redundancies, to get you to your destination. On the Internet, most of the rerouting is dynamic, and happens automatically.

Decentralised strength

Of course, if the biggest highways, called backbones, are backed up, there are delays, but till now there have not been too many. Last year, a main Internet access cable was cut in the South China Sea, traffic slowed down for a few hours, another route was found and connectivity restored.

The very nature of the Internet, its decentralised structure, is its greatest strength. It is a network that has shown resilience. No wonder, it is called the cockroach of the modern age—it survives, it adapts.