Feeds

Routing instability causes net traffic chaos

Interweb routing chart snarl-up

Top 5 reasons to deploy VMware with Tegile

Surfers experienced problems accessing parts of the internet Monday, following the flare-up of router instability problems.

Security watchers pinned the problem on "garbage" being thrown into global BGP (Border Gateway Routing) lookup tables, causing entries to become unnecessarily long. Some backbone routers with older software versions are unable to process this traffic, resulting in sessions getting dropped and problems reaching parts of the internet as a result.

BGP is a core routing protocol which, put simply, maps the best available routes for traffic to flow across the interweb. These routing tables have become snarled up with junk in the loose equivalent of motorists being instructed to go around a roundabout 20 times before proceeding with their journey. As a result traffic has become snarled up and, in some cases, may only be able to access parts of the net via the back-roads.

"The source of the problem appears to be with AS 47868 causing AS paths to become too long," writes 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."

BGP autonomous system (AS) numbers represent unique routing domains, which are typically linked to administrative domains. These work something like place names, indicating the fastest routes on the information super-highway, with the important difference that these routing tables are not fixed but periodically updated.

Danny McPherson, chief security officer at Arbor Networks, explained that routers still running versions of Cisco software older than three years old didn’t allocate enough buffer space for "silly long AS paths, and so they blow chunks when they receive the update".

"However, other vendor implementations and patched versions happily propagate the update, apparently through numerous intermediate ASes, so seemingly random sets of BGP routers in the routing system were taking a dump, or dropping sessions with malformed AS path complaints," he notes.

Similar problems caused global routing instability five years ago, McPherson notes in a detailed technical dissection of the problem here.

The practical upshot of the problem is not altogether clear.

UK traffic stats from LINX look normal, but elsewhere Slashdot reports a "single mis-configured router is apparently able to cause a DOS for a huge chunk of the net". ®

Choosing a cloud hosting partner with confidence

More from The Register

next story
729 teraflops, 71,000-core Super cost just US$5,500 to build
Cloud doubters, this isn't going to be your best day
Want to STUFF Facebook with blatant ADVERTISING? Fine! But you must PAY
Pony up or push off, Zuck tells social marketeers
Oi, Europe! Tell US feds to GTFO of our servers, say Microsoft and pals
By writing a really angry letter about how it's harming our cloud business, ta
SAVE ME, NASA system builder, from my DEAD WORKSTATION
Anal-retentive hardware nerd in paws-on workstation crisis
Microsoft adds video offering to Office 365. Oh NOES, you'll need Adobe Flash
Lovely presentations... but not on your Flash-hating mobe
Cray heaves out even mightier, Lustre-ous Sonexion 2000
Met Office and Los Alamos bomb boffins are apparently among its fans
prev story

Whitepapers

Why cloud backup?
Combining the latest advancements in disk-based backup with secure, integrated, cloud technologies offer organizations fast and assured recovery of their critical enterprise data.
A strategic approach to identity relationship management
ForgeRock commissioned Forrester to evaluate companies’ IAM practices and requirements when it comes to customer-facing scenarios versus employee-facing ones.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Choosing a cloud hosting partner with confidence
Download Choosing a Cloud Hosting Provider with Confidence to learn more about cloud computing - the new opportunities and new security challenges.
New hybrid storage solutions
Tackling data challenges through emerging hybrid storage solutions that enable optimum database performance whilst managing costs and increasingly large data stores.