Thesis (MSc)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: MPLS-based recovery is intended to effect rapid and complete restoration of traffic affected by a fault in a Multiprotocol Label Switching (MPLS) network. Two MPLS-based recovery models have been proposed: lP re-routing which establishes recovery paths on demand, and protection switching which works with pre-established recovery paths. lP re-routing is robust and frugal since no resources are pre-committed but it is inherently slower than protection switching which is intended to offer high reliability to premium services where fault recovery takes place at the 100 ms time scale. This thesis presents an overview of various recovery techniques and addresses the problem of how to find an in some sense optimal set of pre-established traffic engineered recovery paths, given a network with link capacities and traffic demands. We present and motivate our choice of a nonlinear objective function and optimization method for finding traffic engineered working and recovery paths. A variant of the flow deviation method is used to find and capacitate a set of optimal label switched paths. We present and evaluate two simple methods for computing a set of pre-established traffic engineered recovery paths by using the flow deviation method. / AFRIKAANSE OPSOMMING: MPLS-gebaseerde herstel is daarop gemik om verkeer wat deur 'n fout in 'n Multiprotokol Etiketwisseling (Multiprotocol Label Switching) (MPLS) netwerk geaffekteer is, vinnig en volledig te herstel. Twee MPLS-gebaseerde herstelmodelle is voorgestel: Internetprotokol-herroetering (lP rerouting) wat herstelpaaie op aanvraag tot stand bring, en beskermingsoorskakeling (protection switching) wat met voorafbeplande herstelpaaie werk. IP-herroetering is robuust en voordelig aangesien geen netwerkbronne vooraf gereserveer word nie, maar dit is inherent stadiger as beskermingsoorskakeling wat veronderstel is om 'n hoë graad van betroubaarheid aan belangrike dienste te bied waar die herstel van foute in die 100 ms tydskaal plaasvind. Hierdie tesis verskaf 'n oorsig oor verskeie hersteltegnieke en ondersoek die probleem hoe om 'n optimale versameling van voorafbeplande herstelpaaie te vind, gegee 'n netwerk met skakelkapasiteite (link capacities) en verwagte netwerkverkeer. Ons stel voor en motiveer ons keuse van 'n nie-lineêre objekfunksie en optimeringsmetode om verkeersontwerpde (traffic engineered) aktiewe en herstelpaaie te vind. 'n Variant van die vloeideviasie (flow deviation)-metode word gebruik om 'n optimale versameling van etiketwisseling (label switched) paaie te vind en om 'n optimale hoeveelheid kapasiteit aan die paaie toe te ken. Ons stel voor en evalueer twee eenvoudige metodes om 'n versameling van optimale voorafbeplande herstelpaaie te bereken deur die vloeideviasie-metode toe te pas.