We developed a network architecture called information-centric elastic optical transport network (i-CEON) that enables efficient content delivery. The increasing volume of video traffic consumes network resources, so it is necessary to establish optical transport network architectures suitable for content delivery. For this purpose, we extend existing information-centric networking to be applicable to elastic optical networks. The main focus of this paper is presenting the method in i-CEON of optimizing optical-path routing by effectively using an in-network cache function to efficiently accommodate content traffic. This reduces redundant use of network resources. We formulate the joint optimization problem of elastic optical-path routing and content-replication placement as a mixed integer linear programming problem. We conducted intensive numerical experiments to demonstrate the effectiveness of our method and confirmed that it reduced network cost by 20% and server load by 33%.

In this paper, we consider the design of an optical aggregation network with network edge functions virtualization in order to reduce network cost. Here, an optical aggregation network connects a server accommodating virtual network functions (VNFs) with optical line terminals (OLTs) via a time-division-multiplexing (TDM)-based point-to- multipoint (P2MP) wavelength path to aggregate traffic from access networks. Each VNF must be placed on an adequate server in consideration of the efficiency of wavelength paths to reduce network cost. However, existing VNF placement algorithms determines VNF placement without considering the efficiency of P2MP wavelength paths, which deteriorates network performance and increases network cost. To solve the problem, VNF placement must be carried out so that a P2MP wavelength path can be efficiently shared by multiple OLTs for reducing network cost. For this purpose, we propose a VNF placement algorithm, called decomposition-based VNF placement algorithm (DVA), in a TDM wavelength-division-multiplexing (WDM)-based optical aggregation network. The DVA can find approximate solutions of sufficient quality with practical computation time.

NFV (network functions virtualization) enables carrier edge functions to be relocated from dedicated hardware to distributed pools of commodity servers, which reduces network cost and improves robustness to unpredictable demand changes. The key to this lies in how to place each VNF (virtual network function) on an adequate server among pools in conjunction with design of paths connecting servers with OLTs (optical line terminals). There have been extensive studies regarding VNF placement problems, but few have investigated the optimal placement of VNFs in consideration of carrier edge function virtualization. We thus study a design problem of carrier edge VNF placement in an optical aggregation network. We formulate a design problem as MILP (mixed-integer linear programming) and demonstrate the effectiveness of the proposed method through intensive mathematical experiments. The experiments showed that the proposed method reduced the maximum server load and network cost by up to by 29% and 21%, respectively.

Conventional flow-monitoring methods, such as sFlow, cannot detect low-rate HTTP GET Flooding denial of service (DoS) attacks, which are a threat even if the traffic rate is low. To solve this problem, we propose a method for detecting DoS attacks on the basis of the burst-state duration of traffic calculated using a quick packet-matching function of a general router such as TCAM. In addition, we prove that the burst-state duration is a good feature for distinguishing a normal user's traffic from a client to a server and low-rate HTTP-GET-Flooding attacker's traffic. Furthermore, we explain the results of an actual equipment evaluation carried out to evaluate the false-negative rate of our method and sFlow in an actual use case. The result shows that the proposed method is superior under the condition that the attack-traffic rate is low. The results also show that the proposed method can reliably detect such attacks under this condition.

Due to high-density implementation, large-capacity routers are very heavy and consume a huge amount of power. Such routers require the capability for power-supply and air-cooling equipment to be increased. Upon introducing such routers, the physical limitations of the infrastructure should be considered. In addition, wider space in machine rooms to maintain reliability criteria is required, even though space is a precious resource and the purpose of high-density routers is to save floor space. We describe earthquake resistance of high weight, power-supply stability of high power-supply current, and air-cooling reliability of high power consumption. We propose solutions for improved cabinets and power-supply devices and the allocation of this equipment to satisfy network reliability, such as earthquake resistance, power-supply stability, and continuous duration after air-cooling stops. This leads to saving floor area space.

We propose a virtual network edge architecture with a novel wavelength channel add/drop multiplexer configuration using virtualized network functions (VNFs) to save processor and bandwidth resources. The feature of this architecture is VNF live migration with wavelength-division-multiplexing/time-division multiplexing photonic switching technology to use metro network resources efficiently. To reduce the computation of reallocation, the live-migration of a VNF is limited to part of the VNF that contains a larger number of subscribers.

Power consumption of network equipment has been rapidly increasing, so it is therefore necessary to build a resource efficient network (NW). Router virtualization, which involves dynamically reallocating virtual routers to physical resources as a server virtualization, is becoming more common as a way to use network equipment effectively and robustly. Especially, edge router which is gateway of core network should be virtualized, because edge routers have many functions and resources just as servers do. A metro NW is wide area layer-2 aggregation NW that connects each user's residential gateway to edge routers. To achieve edge router virtualization, the metro NW must trace the dynamic edge router reallocation by changing a route of each Ethernet flow. Furthermore, access/metro NWs occupy a large proportion of the total NW power consumption, so logically centralized control architecture suits to the metro NW to change routes flexibly because it can use resources effectively by avoiding resource deployment in many locations. However, it is not scalable. When many Ethernet flows need to be accommodated in a metro NW, it can not change routes of the flows quickly enough. Therefore, we propose a virtual wide area layer-2 switch architecture with scale-out control that can improve the route control performance even in a worst case edge router node failure by processing in parallel flow-by-flow, by considering route information, and by rebalancing the load between parallel processes dynamically. We evaluated the proposed architecture through theoretical analysis and experiments with prototype. The results showed that the proposed architecture can increase the number of flows accommodated in a metro NW.

We consider a mechanism for providing a multi-reliability service in multilayer GMPLS networks. By introducing GMPLS restoration techniques and shared risk link group management, we can provide a highly reliable protected connection service. However, there is a trade-off between reliability and efficiency of network resource usage. In addition, reliability requirements differ depending on the type of service (e.g., Internet access or leased line). Thus, we propose a mechanism for calculating an efficient route for a protected connection that can satisfy specific reliability conditions requested by customers. We also present simulation results that indicate our schemes are remarkably effective for achieving a better balance between end-to-end reliability and efficiency. We also demonstrate the quantitative relationship between availability of service and resource efficiency through simulation experiments

We constructed a rack-mounted prototype photonic ATM switch based on the FRONTIERNET architecture. The advantages of the architecture are that its output-buffering scheme overcomes the bottlenecks that can occur when receiving and storing concurrent high-speed cells, and that there is no need to deal with contention resolution between input highways. The prototype has 16 input/output ports and 2.5 Gb/s transmission speed. Actually, six input ports and one output port are mounted in two racks. We demonstrated successful cell routing and buffering, and its stable operation, with 24-h bit-error-free switching operation. We also discussed problems to be solved in increasing the throughput of FRONTIERNET.

This paper describes large-capacity photonic ATM switching systems being developed that use FDM (or WDM) techniques. Our system is based on a simple star architecture with a modular structure. We show that it is possible to obtain a 320-Gb/s system that has enough S/N margin and can tolerate the polarization and frequency dependencies of optical devices. Our experiments using rack-mounted prototype modules to demonstrate the feasibility of our system, as well as successful 10-Gb/s 4/spl times/4 broadcast-and-select and 2.5-Gb/s 16/spl times/16 frequency-routing switch operations.