The slowdown, which effected worldwide internet access on Monday morning and afternoon, was down to problems with overly long global BGP (Border Gateway Routing) autonomous system (AS) numbers.
Several readers have reported difficulty in reaching parts of the Internet today. The source of the problem appears to be with AS 47868 causing AS paths to become too long,” said Marcus H. Sachs, director of the SANS Internet Storm Center.
“Not much you can do about it unless you have access to your BGP router, in which case you might want to either block AS 47868 or limit the length of any AS path.”
The problems have apparently been traced to a router run by Czech ISP SuproNet, which issued a router update which caused some other routers running older firmware. The overly long AS numbers caused delays in processing data traffic said internet monitoring firm Renesys.
“We experienced an almost 100-fold increase in the rate of routing updates from our worldwide array of sensors,” said the company in a blog posting.
“We were heartened to see that most of Internet's core survived a single odd announcement, but this does speak to a lot of outdated equipment or software at the edge. And if you manage to get all of edge routers to reset, you aren't going to have many people to talk to no matter what the core is doing.”
“While it might be tempting to bash SuproNet, can anyone really defend a system where a failure in probably one of the weaker links can cause the entire system to unravel?”
The company pointed out that the bulk of the problems were with older routers, so less developed markets like Africa took the hardest hit, but networks were seriously affected in Europe (particularly France) and the United States.