As the Software Defined Networking (SDN) paradigm gains momentum, every network operator faces the obvious dilemma: when and how to migrate from existing IP routers to SDN compliant equipments. A single step complete overhaul of a fully functional network is impractical, while at the same time, the immediate benefits of SDN are obvious. A viable solution is thus a gradual migration over time, where questions of which routers should migrate first, and whether the order of migration makes a difference, can be analyzed from techno economic and traffic engineering perspective. In this paper, we address these questions from the techno economic perspective, and establish the importance of migration scheduling. We propose optimization techniques and greedy algorithms to plan an effective migration schedule, based on various techno economic aspects, such as technological gains in combinations with CapEx limitations. We demonstrate the importance of an effective migration sequence through two relevant network management metrics, namely, number of alternative paths availed by a node on migration, and network capacity savings. Our results suggest that the sequence of migration plays a vital role, especially in the early stages of network migration to SDN.
This paper extends our recent studies on network migration. In @cite_5 , we proposed an agent-based model to study benefits of joint migration to multiple technologies, on a case study of Path Computation Element (PCE) and SDN. In @cite_7 , we defined the SDN , and found optimal solution. In this paper, however, our focus is entirely on devising computationally inexpensive but effective heuristics to schedule migration to a single technology, with consideration of techno-economic factors, such as limitations on CapEx investment. To this end, we propose novel greedy algorithms and establish their practical impact in terms of computational complexity, run times, network capacity gains, etc.
@cite_5 @cite_7
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Conventionally, network migration models study competition between emerging and incumbent technologies by considering the revenue increase and migration cost. We propose to extend the existing network migration models with new critical factors, including (i) synergistic relationships across multiple technologies, (ii) reduction in operation expenditures (OpEx), and, (iii) effect of social factors on human decisions. To this end, we propose a novel agent-based migration model considering these factors. Based on the model, we analyze the case study of optimal path computation with joint migration to two emerging networking paradigms, i.e., IETF Path Computation Element (PCE) and Software-Defined Networking (SDN). Our results demonstrate the synergistic effects of migration to multiple complementary technologies, and shows that a technology migration may be eased by the joint migration to multiple technologies. In this paper, we analyze the question of network migration to Software Defined Networking (SDN) from the perspective of Traffic Engineering (TE). For a given network topology and migration planning horizon, we ask the question of which routers in the IP network should migrate to SDN-enabled operation to reduce the need for network capacity upgrades over a given time horizon. We propose an algorithm to determine the optimum schedule for node substitution within a network, which shows that already a few SDN routers, when strategically located, provide a stably large number of path alternatives to be used in TE, thus substantially reducing the need for large network capacity upgrades. Distributed controller architectures have been proposed for Software-Defined Networking (SDN) to ensure scalability and reliability. One major drawback of the existing architectures is the uneven load distribution among controllers stemming from the static binding between controllers and switches. To address this issue, several existing studies introduce dynamic binding by adopting some switch migration mechanisms that re-associate switches from overloaded controllers to underutilized controllers. However, the migration process adds a considerable amount of complexity to the system and may incur significant network latency. In this paper, we propose BLAC, a novel BindingLess Architecture for distributed Controllers (BLAC), in which load balance is achieved with the help of the proposed scheduling layer, which intercepts flow requests from switches and dispatches them to different controllers as determined by selected scheduling algorithms. The process is proceeded transparently with no extra modification required for off-the-shelf SDN switches. Besides, the scheduling layer can flexibly support various scheduling algorithms and causes neither disruption of service nor significant network delay. We build a prototype that can work with various distributed controller systems and conduct experiments to demonstrate its efficacy. The results show that our design outperforms the static-binding controller system in terms of both system throughput and response time without the complexity of the dynamic-binding controller system. Virtualizing network functions is becoming a major trend in today's research on cloud computing. Among networking elements, the Home Gateway appears to be one with the most diverse functions to handle and thus, with great potential for virtualization. To this end, the paper proposes a solution to ease adoption by Service Providers of the latest breakthroughs in cloud computing technologies towards a virtualized Home Gateway. Although the NFV approach globally pretends bringing operational advantages in terms of CAPEX and OPEX, it is essential to prove them for Home Gateways scenarios where compatibility and versatility are strong requirements. To achieve this goal, we introduce the concept of Surrogate vNF, which makes Home Gateways NFV aware. The paper highlights a migration path towards full Home Gateway virtualization and proves its concept through a real implementation and a simulated evaluation on a practical use case related to video content distribution.