A novel survivable IP over WDM network design problem is proposed. The IP network uses lightpath services of the WDM network to implement its IP links. The WDM network can provide unprotected and protected lightpaths, as well as a new lightpath service referred to as survivable pair. The IP network must support two traffic matrices, one under normal conditions and the other whenever there is a ...

We investigate topologically biased failure in scale-free networks with a degree distribution P(k) proportional, variantk;{-gamma}. The probability p that an edge remains intact is assumed to depend on the degree k of adjacent nodes i and j through p_{ij} proportional, variant(k_{i}k_{j});{-alpha}. By varying the exponent alpha, we interpolate between random (alpha=0) and systematic failure. Fo...

background quality of health services is one of the most important factors for delivery of these services. regarding the importance and vital role of quality in the health sector, a concept known as “clinical governance” (cg) has been introduced into the health area which aims to enhance quality of health services. thus, this study aimed to assess private and public hospitals’ readiness to impl...

Intra-domain routing in IP backbone networks relies on link-state protocols such as IS-IS or OSPF. These protocols associate a weight (or cost) with each network link, and compute traffic routes based on these weights. However, proposed methods for selecting link weights largely ignore the issue of failures which arise as part of everyday network operations (maintenance, accidental, etc.). Chan...

Failure injection in distributed systems has been an important issue to experiment with robust, resilient distributed systems. In order to reproduce real-life conditions, parts of the application must be killed without letting the operating system close the existing network communications in a ”clean” way. When a process is simply killed, the OS closes them. SystemTap is a an infrastructure tha...