Service Function Chaining (SFC) allows the forwarding of a traffic flow along a chain of Virtual Network Functions (VNFs, e.g., IDS, firewall, and NAT). Software Defined Networking (SDN) solutions can be used to support SFC reducing the management complexity and the operational costs. One of the most critical issues for the service and network providers is the reduction of energy consumption, which should be achieved without impact to the quality of services. In this paper, we propose a novel resource allocation architecture which enables energy-aware SFC for SDN-based networks. To this end, we model the problems of VNF placement, allocation of VNFs to flows, and flow routing as optimization problems. Additionally, we model the problem of flow rerouting to reduce the impact of resource fragmentation on the network utilization. Thereafter, heuristic algorithms are proposed for the different optimization problems, in order to find near-optimal solutions in acceptable times. The performances of the proposed algorithms are numerically evaluated over a real-world topology and various network traffic patterns. The results confirm that the proposed heuristic algorithms provide near-optimal solutions while their execution time is applicable for real-life networks.

Middleboxes have become a vital part of modern networks by providing services such as load balancing, optimization of network traffic, and content filtering. A sequence of middleboxes comprising a logical service is called a Service Function Chain (SFC). In this context, the main issues are to maintain an acceptable level of network path survivability and a fair allocation of the resource between different demands in the event of faults or failures. In this paper, we focus on the problems of traffic engineering, failure recovery, fault prevention, and SFC with reliability and energy consumption constraints in Software Defined Networks (SDN). These types of deployments use Fog computing as an emerging paradigm to manage the distributed small-size traffic flows passing through the SDN-enabled switches (possibly Fog Nodes). The main aim of this integration is to support service delivery in real-time, failure recovery, and fault-awareness in an SFC context. Firstly, we present an architecture for Failure Recovery and Fault Prevention called FRFP; this is a multi-tier structure in which the real-time traffic flows pass through SDN-enabled switches to jointly decrease the network side-effects of flow rerouting and energy consumption of the Fog Nodes. We then mathematically formulate an optimization problem called the Optimal Fog-Supported Energy-Aware SFC rerouting algorithm (OFES) and propose a near-optimal heuristic called Heuristic OFES (HFES) to solve the corresponding problem in polynomial time. In this way, the energy consumption and the reliability of the selected paths are optimized, while the Quality of Service (QoS) constraints are met and the network congestion is minimized. In a reliability context, the focus of this work is on fault prevention; however, since we use a reallocation technique, the proposed scheme can be used as a failure recovery scheme. We compare the performance of HFES and OFES in terms of power consumption, average path length, fault probability, network side-effects, link utilization, and Fog Node utilization. Additionally, we analyze the computational complexity of HFES. We use a real-world network topology to evaluate our algorithm. The simulation results show that the heuristic algorithm is applicable to large-scale networks.

No abstract

There are two main scalable methods for streaming live video over the Internet: Content Delivery Networks (CDNs) and Peer-to-Peer (P2P) networks. Though both have their own problems, P2P streaming systems challenge delivering video with constant quality and CDNs approaches require deployment of large number of servers throughout the Internet that is costly. Recently, using hybrid architectures based on both CDN and P2P networks has shown to be an efficient approach for large-scale video distribution over the Internet. This paper is compared the performance of two main hybrid CDN-P2P architectures includes: (i) CDN-P2P unconnected mesh in which independent P2P mesh networks are constructed under each CDN node, and (ii) CDN-P2P connected mesh in which CDN nodes and peers participate in construction of a single P2P mesh network. The comparison is preformed in addition, to the pure mesh-based P2P video streaming, using extensive simulation and based on different QoS metrics.

No abstract