Accession Number : ADA320308

Title :   Performance Analysis of Dynamic Routing Protocols in a Low Earth Orbit Satellite Data Network.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH

Personal Author(s) : Janoso, Richard F.

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Report Date : DEC 1996

Pagination or Media Count : 120

Abstract : Modern warfare is placing an increasing reliance on global communications. Currently under development are several Low Earth Orbit (LEO) satellite systems that propose to deliver voice and data traffic to subscribers anywhere on the globe. However, very little is known about the performance of conventional routing protocols under orbital conditions where the topology changes on a scale of minutes rather than days. This thesis compares two routing protocols in a LEO environment. One (Extended Bellman-Ford) is a conventional terrestrial routing protocol, while the other (Darting) is a new protocol which has been proposed as suitable for use in LEO networks. These protocols are compared via computer simulation in two of the proposed LEO systems (Globalstar and Iridium), under various traffic intensities. Comparative measures of packet delay, convergence speed, and protocol overhead are made It was found both protocols were roughly equivalent in end-to-end delay characteristics, though the Darting protocol had a much higher overhead load and demonstrated higher instability at network update periods. For example, while steady state end-to-end delays were within a few milliseconds, in one case Darting showed an increase of 764% in convergence time over Extended Bellman-Ford with an increase of 149% in overhead. Over all cases, Darting required an average of 72.1% more overhead than Extended Bellman-Ford to perform the same work. Darting was handicapped by its strong correlation between data traffic and protocol overhead. Modifications to reduce this overhead would result in much closer performance.

Descriptors :   *COMMUNICATIONS TRAFFIC, *DATA TRANSMISSION SYSTEMS, *PERFORMANCE TESTS, *ROUTING, *SATELLITE NETWORKS, *TIME STUDIES, *GLOBAL COMMUNICATIONS, COMPUTERIZED SIMULATION, STEADY STATE, EARTH ORBITS, LOW ORBIT TRAJECTORIES, DYNAMICS, INTENSITY, THESES, TIME, TOPOLOGY, ARTIFICIAL SATELLITES, MILITARY APPLICATIONS, CONVERGENCE, DELAY, INSTABILITY.

Subject Categories : UNMANNED SPACECRAFT
      TELEMETRY

Distribution Statement : APPROVED FOR PUBLIC RELEASE

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