BGP ist often used in order to Censor the Internet on behalf of the government.
From the technical side this is an interesting process when asking yourself “How would a government shutdown the Internet if they had/want to – and is this even possible?”
Well, the current situation in Egypt shows that a goverment backened takedown is possible.
From the bgpmon blog: http://bgpmon.net/blog/?p=450
Different media are reporting that Internet and other forms of electronic communications are being disrupted in Egypt. Presumably after a government order in response to the protests. Looking at BGP data we can confirm that according to our analysis 88% of the ‘Egyptian Internet’ has fallen of the Internet. In this post I’ll share some observations I made with regards to the reachability of Egyptian networks and providers.
The article lists the biggest ISPs in Egypt and the current prefix changes made. Using the Autonomous System Nr. (ASN), you can visualize the BPG route announcements.
The most noteable prefix changes involve AS8452 AS24863 and AS36992.
Go to http://bgplay.routeviews.org (requires Java) and set the timeframe around 2011-01-27 at around 10PM and watch.
With all prefixes removed, LINKdotNET-AS using AS24863 and the Prefix 18.104.22.168/17 shows the greatest impact.
By the way, one of the most noteable events in the last years involving BGP was the failed censorship of youtube by Pakistan Telecom. I recommend watching this video before looking at the Egypt situation because it includes commentary on what is happening.