MCLC: internet outage

[Denton, Kirk]

MCLC LIST
From: kirk (denton.2 at osu.edu)
Subject: internet outage
***********************************************************

Source: The Wall Street Journal (4/13/12):
http://blogs.wsj.com/chinarealtime/2012/04/13/new-clarity-on-china-internet
-outage/

New Clarity on China Internet Outage

When China¹s internet goes haywire, it¹s not just eager microblog users
who notice. Thursday¹s two-hour blip, during which a chunk of China¹s
internet traffic stopped
<http://blogs.wsj.com/chinarealtime/2012/04/12/mystery-outages-put-china-in
ternet-on-edge/>, likely set off alarm bells at major internet companies
across the globe as they scrambled to ensure their networks weren¹t the
ones blocking Chinese traffic.

One such company, CloudFlare <https://www.cloudflare.com/> ‹ which
provides web performance and security services for hundreds of thousands
of small websites and which claims to handle more traffic than Amazon.com,
Twitter, Wikipedia, Apple.com and Bing combined ‹ similarly scrambled
their engineers to check on the disappearing China traffic.

CloudFlare chief executive and co-founder Matthew Prince said the company
quickly realized the problem wasn¹t on its side. But what they did
discover sheds some light on the blackout.

The company found that traffic from China Telecom and China Unicom¹s
networks both plummeted between 11 am and 1 pm on Thursday while traffic
from other smaller networks, like that operated by China Mobile and China
Railway, were relatively unaffected.

===========================================
Chart 1: Traffic to CloudFlare¹s network from China Telecom on Thursday,
April 12 (GMT):
CloudFlare
Chart 2: Traffic to CloudFlare¹s network from China Unicom on Tuesday,
April 12 (GMT):
CloudFlare
Chart 3: Traffic to CloudFlare¹s network from China Mobile on Tuesday,
April 12 (GMT):
CloudFlare
===========================================
The company¹s engineers also found that, contrary to what would be
expected if the blackout were due to an equipment failure or break in an
undersea cable ­ as many originally speculated after Wednesday¹s magnitude
8.6 earthquake near Indonesia ­ only certain types of data had stopped
flowing. China Telecom and China Unicom HTTP traffic ­ connections between
clients and sites directly ­ mostly stopped, but other types of traffic
that flow through different ports like Skype calls, email transfers and
DNS traffic (which functions like a phone book to link a web address with
an IP address) continued to flow.

Although Mr. Prince stresses that their conclusions remain speculative, he
said the fact that non-HTTP traffic continued likely points to the cut off
being the result of web filtering. An engineer at his firm who declined to
be named said: ³Non-HTTP (or DNS) traffic was able to pass, which suggests
that someone made a mistake when filtering something ­ likely they
filtered the entire internet.²

Whether that sort of filtering was an accident or some sort of test of an
internet ³kill switch² (as has been suggested by some others
<http://www.techinasia.com/infrastructure-problem-china-unicomtelecom-inter
net-issues/>), is almost certain to remain a mystery.

­ Paul Mozur. Follow him on Twitter @paulmozur
<http://www.twitter.com/paulmozur>