A five-day Internet shutdown in Egypt failed to stop the protests that forced President Hosni Mubarak to resign. 
埃及互联网关闭5天，却没能阻止迫使总统胡斯尼·穆巴拉克辞职的抗议行动。

But it raised a technical question. 
但这也提出了一个技术上的问题。

Just how were Egyptian officials able to shut down Internet service in their country?
即埃及政府官员如何能够关闭国内互联网服务？

Craig Labovitz is chief scientist at Arbor Networks, an Internet security company in the American state of Michigan. 
阿伯网络是一家位于美国密歇根州的网络安全公司，公司首席科学家是克雷格·拉伯维兹。

Mr. Labovitz says the Internet is not as indestructible as people might think. 
拉伯维兹表示，互联网并非人们所想的那样不可摧毁。

He says there are points where the flow of computer traffic can be restricted.
他说，其中有一些节点，在这些节点上就可以限制计算机通信流量。

"From a technical standpoint, the popular imagination of the Internet is as a network that can survive nuclear wars, can't be stopped, is everything, everywhere. 
从技术角度来看，对互联网通常的想象就是这是一个可以从核战争中幸存下来、不可阻止的网络，这个网络就是一切，它无处不在。

But the engineering realities are a lot more prosaic. 
但网络工程的真相却要乏味得多。

In many countries there are a few natural bottlenecks, whether it be large data centers or right-of-ways."
在很多国家，网络有一些天生的瓶颈——不管是大型数据中心方面还是网络通行权方面。

Mr. Labovitz says his researchers tracked the Internet shut down in Egypt as it was being carried out. 
拉伯维兹称，埃及互联网关闭期间，他的研究员们对其过程进行了跟踪。

He explains that in Egypt, Internet users connect to the outside world through a small number of providers with international links.
他解释说，埃及的网络用户通过为数不多的国际联网提供商跟外界联系。

"Although there are 100 or more providers within the country -- domestic providers -- there really are only four providers that maintain external links to the external world. 
尽管埃及国内的网络提供商有100个或更多——这些国内提供商——但其实只有4家提供商运营跟外界联系的国外联网。

And there's an even a smaller number of data centers where the fiber optics cross Egypt. 
而有光纤经过埃及境内的数据中心的数量就更少了。

So you really just need to turn off a handful of machines to have this type of disruption."
所以你其实只需关闭少数几台机器就能中止网络服务。

News reports suggested that the fiber optic links for those networks are even all housed in the same building.
新闻报道显示，那些网络的光纤链接甚至都置于同一座建筑物内。

Could a similar Internet shutdown take place in the United States? 
类似的网络服务关闭现象会在美国发生吗？

Craig Labovitz says that is less of a possibility because of a larger number of Internet providers and data centers.
克雷格·拉伯维兹表示这种可能性比较小，因为美国的网络提供商和数据中心数量很多。

Still, the recent shutdown in Egypt has raised new concerns about a proposal in the United States Congress. 
但埃及最近的网络关闭再次引起了人们对国会一项提案的关注。

Critics say the legislation could make similar action possible in America.
批评者称，该法规使在美国发生类似的事件成为可能。

The measure is known as the Protecting Cyberspace as a National Asset Act. 
该议案叫做“像保护国有资产网络空间法案”（PCNAA）。

Senator Joseph Lieberman of Connecticut first proposed the bill last June. 
康涅狄格州参议员约瑟夫·利伯曼于去年6月首次提出。

Supporters say it would help protect the country's economic and national security from cyber attack. 
法案支持者认为这样有助于保护国家经济和国家安全免遭网络袭击。

It would give the president the emergency power to shut down or seize parts of the nation's Internet in the event of a major threat.
根据该法案，总统将有权在面临重大事件威胁时紧急关闭或控制国内的部分网络。

Critics say the bill would give the president too much power. 
批评者认为该法案会赋予总统过多的权力。

Some people call it the "Kill Switch Bill" -- an easy way to shut off the Internet. 
一些人则称之为“开关毁灭法案”，因为这样一来关闭互联网将变得很容易。

They say the government could use it to censor the Web and control the flow of information.
他们称政府可以因此对网络内容进行审查，并控制信息的传播。