Keio University, Graduate School of Media and Governance
MAUI Project
Ph.D. Dissertation

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ACADEMIC YEAR 2007 ( February 27th, 2008 )
NAME OHARA, Yasuhiro
TITLE Routing Architecture for the Dependable Internet

Intra-domain routing technology to forecast and improve network availability is discussed in this dissertation, as a first step toward the Dependable Internet.

The current Internet consists of combinations of reliability research technologies for individual components. The combinations do not improve practical reliability of entire communication network sufficiently because of two reasons. First, research on reliability does not cover all network components. Second, no fall-back plan is provided when the responsible reliability technology fails. Consequently communication network may cease to function until it is manually repaired. The reliability of Internet is not yet sufficient for mission critical communications.

This dissertation realizes forecast and improvement of the network availability of communication network. The method of provisioning multipath routes aggressively in advance and bypassing failures stochastically is provided. Routing technologies required for highly available Internet are constructed without adding any complex notion.

This dissertation contributes to improvements of network availability by the proposals of : 1) a simulator "SimRouting" to calculate network availability considering routing methods and to evaluate routing methods, 2) a method to stabilize OSPF, as a contribution to reliability research to cover all components, 3) a novel routing algorithm "MARA" that calculate many multipaths in hop-by-hop networks, 4) a novel routing architecture "Drouting" where connection reestablishment is assigned to another path within multipaths randomly, and 5) a network optimization method on Drouting architecture.

Routing technologies have remained for approximately 30 years as the single shortest-path routing. Considering feasibility, this dissertation introduces a new notion of using maximum number of alternative paths. The new routing architecture decouples failure detection and path change function, and enables the flexible utilization of them. The routing architecture is expected to be extended for new features such as Quality of Service based routing. A proposal of fundamental routing architecture for the next generation Internet is given.

Keyword: Multipath Routing, Routing Algorithm, Routing Architecture, Network Reliability, Network Availability, Failure Avoidance

CONTACT To obtain the whole paper, please contact;
OHARA, Yasuhiro ( yasu at )

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