| There is a growing interest
among service providers to offer their customers new revenue-generating
services with Quality of Service (QoS) guarantees e.g., Virtual Private
Networks (VPNs). This is facilitated by current efforts to provide resource
reservations and explicit path routing, e.g., Multi- Protocol Label Switching
(MPLS). A key requirement for such services is that they also be resilient
to failures. This goal can be achieved by provisioning primary and restoration
paths that satisfy the QoS constraints.
We undertake a comprehensive
study of problems related to finding QoS Paths with Restoration. We consider
both bottleneck QoS constraints, such as bandwidth, and additive QoS constraints,
such as delay and jitter. This is the first study to provide a rigorous
solution, with proven guaranties, to the combined problem of computing
QoS paths with restoration. It turns out that the widely used approach
of disjoint primary and restoration paths is not an optimal strategy. Hence,
the proposed algorithms construct a restoration topology, i.e., a set of
bridges, each bridge protecting a portion of the primary QoS path. This
approach guaranties to find a restoration topology with low cost when one
exists.
Joint work with Y. Bejerano,
Y. Breitbart, A. Orda, R. Rastogi |
