Survivable virtual network mapping to provide content connectivity against double-link failures

Abstract

In recent years, large scale natural disasters (such as earthquakes, or tsunami) have caused multiple Internet outages in different parts of the world, resulting in high infrastructures damages and capacity losses. Content providers are currently investigating novel disaster-resiliency mechanisms to maintain the service continuity in their Content Delivery Networks (CDNs). In case of such widespread failures, the content providers might not be able to guarantee Network Connectivity (i.e., the reachability of all nodes from any node in the network) and researchers have started investigating the concept of Content Connectivity (i.e., the reachability of the content from any point of the network), that can be achieved even when the network is disconnected, as long as a replica of the content can be retrieved in all the disconnected components of the network. In this paper we focus on double-link failures and consider different combinations of content connectivity and network connectivity. As guaranteeing network connectivity against double-link failures may result in very high network-resource consumption, in this work we present an Integer Linear Programming (ILP) formulation for survivable virtual network mapping to guarantee the network connectivity after single-link failures and maintain the content connectivity after double-link failures. We show that maintaining content connectivity against double-link failures costs almost the same, in terms of network resources, as providing network connectivity against single-link failures. We also investigate the trade-off between datacenter placement and the amount of resources needed to provide content connectivity in case of double-link failures

Logical Network Mapping With Content Connectivity Against Multiple Link Failures in Optical Metro Networks

“…In case of NC-1, this work is similar to [5]. Compared to [2], [3], and [5], our approach better prepares networks for an arbitrary number of physical link failures under disaster conditions.…”

“…In this section, we compare complexity of our problem formulation to complexity in [2] and [3]. We also evaluate the cost in terms of number of wavelength channels of CC in various scenarios.…”

“…In [2], the authors solved the CC problem against single-link failures. In [3], the authors extended the CC problem to doublelink failure scenarios. In both works, the CC problem was examined for backbone optical networks with mesh topologies.…”

“…Our contributions can be summarized as follows. First, we propose a problem formulation that is more scalable than the ones in [2] and [3]. By improving scalability, our work can not only cope with larger networks with a higher number of nodes and links but can also concurrently preserve problem optimality.…”

A survey of strategies for communication networks to protect against large-scale natural disasters

“…The concept of content connectivity was first introduced in [40], where the authors developed an Integer Linear Program (ILP) model that guarantees content connectivity against single-link failures. Following the same methodology, the authors in [41] formulated a more practical version of the Survivable Virtual Network Mapping (SVNM) problem, where network connectivity is guaranteed against any single failure, while content connectivity is guaranteed against any double-link failures. Finally, a generalization of the content connectivity concept, referred to a k-content connectivity, has been proposed to ensure that any node in the network can still reach the content after k−1 link failures in [42], where a flexible and cost-saving algorithm of the problem is also presented.…”