Method and apparatus for improving the resilience of content distribution networks to distributed denial of service attacks

摘要

Several deterrence mechanisms suitable for content distribution networks (CDN) are provided. These include a hash-based request routing scheme and a site allocation scheme. The hash-based request routing scheme provides a way to distinguish legitimate requests from bogus requests. Using this mechanism, an attacker is required to generate O(n2)amount of traffic to victimize a CDN-hosted site when the site content is served from n CDN caches. Without these modifications, the attacker must generate only O(n) traffic to bring down the site. The site allocation scheme provides sufficient isolation among CDN-hosted Web sites to prevent an attack on one Web site from making other sites unavailable. Using an allocation strategy based on binary codes, it can be guaranteed that a successful attack on any individual Web site that disables its assigned servers, does not also bring down other Web sites hosted by the CDN.