Sara Ayoubi

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We propose in this paper a new approach for the dynamic enforcement of Web services security, which is based on a synergy between Aspect-Oriented Programming (AOP) and composition of Web services. Security policies are specified as aspects. The elaborated aspects are then weaved (integrated) in the Business Process Execution Language (BPEL) process at(More)
—This paper deals with the problem of proactive survivability of Virtual Networks (VNs) residing in a cloud data center. In all of the previous work, the protection schemes consists of augmenting the VNs with a predetermined number of backup nodes. Further, to reduce the amount of provisioned resources, various backup resource sharing schemes are(More)
In cloud data centers, where hosted applications share the underlying network resources, network-bandwidth guarantees have been shown to improve predictability of application performance and cost. However, recent empirical studies have also shown that often data center devices and links are not all that reliable and that failures may cause service outages,(More)
Virtual network embedding (VNE) is defined as the allocation of network resources to multiple virtual networks (VNs) and is recognized to be a challenging task to perform efficiently. Virtual network survivability is a new term that describes the measures taken to provide a failure-proof VN against physical link and/or node failure. Indeed, a single link or(More)
Network virtualization enables the multi-tenancy concept and paves the way towards more advancements and innovation in the underlying infrastructure. With network virtualization, allocating resources to Virtual Networks (VNs) that represent tenants' requests emerges as a challenging problem. This problem is commonly known as the Virtual Network Embedding(More)
Network virtualization enables the multi-tenancy concept where multiple tenants's services can cohabit the same substrate network and share its resources. With multi-tenancy, the problem of allocating resources to the various tenants emerges as a challenging problem. This former is commonly known as the virtual network embedding problem (VNE), which has(More)
In a virtualized infrastructure where multiple virtual networks or tenants are running atop the same physical network e.g., a data center network, a single facility node e.g., a server failure can bring down multiple virtual machines, disconnecting their corresponding services and leading to millions of dollars in penalty cost. To overcome losses, tenants(More)