Yesterday we noted how a single errant BGP announcement by an unknown Czech ISP created brief outages at several large hosting companies. In subsequent discussion at Slashdot and elsewhere, there has been skepticism about whether the problems were all that serious. Renesys, which monitors Internet routing, has published a detailed analysis that quantifies the incident's impact, saying the update from Czech provider Supronet "single-handedly caused a global Internet meltdown for upwards of an hour." An excerpt:
While most of the core routers run by major ISPs fared just fine, processing the ridiculous path and sending it on, others choked. Perhaps they weren't as well maintained or were running buggy software. These routers viewed the update as malformed and so tore down their session with whoever sent them the update. In other words, two routers that were happily exchanging traffic with each other just moments before suddenly stopped all communication. ... Multiply this by thousands of routers around the world and you can begin to appreciate the ensuing pandemonium.
Renesys said its sensor network saw a 100-fold jump in routing updates. Will this prompt efforts to better maintain or police Internet routing system? Similar issues were widely discussed a year ago following the YouTube hijacking, and here we are again. Here's a key point: While the incident was widespread, it was also brief. Major Internet routing snafus are noticed quickly and addressed quickly, and the network goes on about its business of routing around problems.