The Internet may does not meet all the demands required by applications sensitive to delay. Voice, video or even game applications demand low delay. The distance of hops between client and server, link traffic and the randomness of the packet path, may cause delays. There is motivation and even implementation of alternative infra-structure to improve access. This book proposes a high speed infra-structure network, exclusive for delay sensitive applications. This network, named IXnet, has it''s origins in experiments with shared routing IXP, traffic studies of a sensitive to delay application and use of network simulator. The use of IXnet may increase the business front for operators and users that utilize sensitive to delay applications, improving the quality of the services provided.