Cisco router snafu disconnects Japan from the Net

Posted by Humphrey Cheung

Tokyo Japan - Thousands of Cisco routers belonging to Nippon Telephone and Telegraph East failed on Tuesday and knocked out millions of Japanese broadband Internet customers.  According to Network World, 2000 to 4000 routers failed to forward data packets when their routing tables overflowed.  This resulted in a 7 hour outage and many angry customers.

The outage was concentrated to eastern Japan where NTT East is testing out Cisco routers.  NTT West is using routers from Cisco’s archrival Juniper Networks.  Cisco representatives did not say which router models were affected.

Routers maintain tables to figure out which links are available and have the most bandwidth.  Decent routers can change the path that the data takes, if a neighboring router goes down.  Apparently the outage happened when NTT technicians tried to switch simulate a failure by switching over to backup routes.

Read more … Network World via Computer World Singapore .