Yeunwoong Kyung

Software defined service migration through legacy service integration into 4G networks and future evolutions

With the ongoing worldwide deployment of 4G networks and consequent drop of the utilization ratio of legacy networks, network operators need a cost-effective way to flexibly operate and manage networks. The obligatory continuation of legacy services in their respective legacy networks consistently incurs OPEX. In this situation, we argue that network operators can benefit from the recent advances in SDN and NFV. This article introduces a blueprint for designing a novel network architecture that integrates legacy network services into 4G networks through SDN/NFVs software-based characteristics. In addition, our architecture reduces time to market for employing newly emerging services without mandating any changes in 4G infrastructures.

Mobile flow-aware networks for mobility and QoS support in the IP-based wireless networks

Abstract As the volume of mobile traffic consisting of video, voice, and data is rapidly expanding, a challenge remains with the mobile transport network, which must deliver data traffic to mobile devices without degrading the service quality. Since every Internet service holds its own service quality requirements, the flow-aware traffic management in fine granularity has been widely investigated to guarantee Quality of Service (QoS) in the IP networks. However, the mobile flow-aware management has not been sufficiently developed yet because of the inherent constraints of flow routing in the mobile networks regarding flow-aware mobility and QoS support. In this paper, we propose a flow-aware mobility and QoS support scheme called mobile flow-aware network (MFAN) for IP-based wireless mobile networks. The proposed scheme consists of dynamic handoff mechanisms based on QoS requirements per flow to reduce the processing overhead of the flow router while ensuring QoS guarantee to mobile flows. The performance analyses of the proposed scheme demonstrate that MFAN successfully supports the mobile flow traffic delivery while satisfying the QoS requirement of flows in the wireless mobile IP networks.

A load distribution scheme over multiple controllers for scalable SDN

In this paper, we propose a load distribution scheme on a per-flow basis over multiple controllers in SDN (Software-Defined Networking). Specifically, when the capacity of a controller reaches a threshold, the controller makes incoming messages be migrated to other controllers to prevent them from being blocked. Analytical results show that our scheme has lower blocking probability and higher controller capacity utilization ratio than the conventional scheme.

QoS-aware dynamic resource allocation for wireless broadband access networks

The development of the advanced wireless access technologies is focusing on the enhancement of mobile user satisfaction in terms of quality of service (QoS). As the number of mobile users increases, the amount of traffic passing through base station (BS) significantly increases so that the preplanned capacity of downlink or uplink can be exceeded from time to time resulting in the degradation of users’ QoS satisfaction. A way to utilize the downlink (DL) and the uplink (UL) of an orthogonal frequency division multiple access frame efficiently is therefore needed subject to users’ bandwidth demand which changes continuously over the time. In this paper, we propose a QoS-aware dynamic resource allocation (QDRA) scheme which dynamically adjusts the DL/UL ratio to allocate bandwidth for QoS support to users based on the usage statistics. The performance of the proposed QDRA scheme was examined by applying to the WiMAX standard specifications, to show its superiority of maintaining a higher QoS support for various classes of services compared to the pre-reported adaptive method.

Mobility-aware load distribution scheme for scalable SDN-based mobile networks

As the network grows, the centralized SDN (Software-Defined Networking) architecture causes a scalability problem. To handle this problem, multiple controllers have been used in many related works. However, if the load is concentrated on a certain controller, incoming messages to the controller can be blocked while other controllers are not busy. Especially, this problem becomes critical for handover requests in mobile networks because users will perceive severe QoS deterioration when these requests are blocked. Therefore, this paper presents a mobility-aware load distribution scheme for scalable SDN-based mobile networks. In the proposed scheme, incoming handover request messages can be differentiated among other messages and admitted with priority. In addition, these messages can be migrated to other controllers when the controller has no capacity to prevent them from being blocked. Analytical results confirm that the proposed scheme has lower blocking probability and higher resource utilization ratio than conventional schemes without much additional signaling load as offered load increases.

A provisioning scheme for guaranteeing recovery time in WDM mesh networks

This paper proposes a new provisioning scheme of the WDM networks to guarantee the recovery time defined in service level agreement (SLA). In our proposed scheme, the fault management scheme and working path or a pair of paths are selected based on the comparison of the pre-calculated recovery time with the recovery time required by the customer in resource efficient manner. Simulation results show that the proposed scheme outperforms the conventional schemes such as dedicated and shared path protection in terms of recovery time satisfaction ratio and resource utilization ratio.

A mobility-aware flow admission control scheme in OpenFlow-based mobile networks

This paper proposes a mobility-aware flow admission control scheme in OpenFlow based mobile networks. Proposed scheme performs classification of the input messages at the control plane considering mobility and types of services. Then, different amount of capacities are allocated according to the class for prioritized admission control. Proposed scheme is evaluated in terms of blocking probability and average waiting time in the control plane. The analytical results demonstrate that proposed scheme has both lower blocking probability and average waiting time for high prioritized messages.

SDN/NFV-based scalable mobile service integration for gradual network evolution

The coexistence of heterogeneous networks is becoming increasingly more common with the evolution towards 5G, increasing the complexity and cost of deploying and managing these networks. Network operators consequently need to find efficient ways of flexibly constructing and operating networks within a heterogeneous network environment in order to reduce operational expenditure (OPEX) and capital expenditure (CAPEX). One possible way to meet this requirement is the accommodation of previous legacy network services in the newly-deployed network while gradually reducing the reliance on physical legacy networks. Software-defined transitional network (SDTN) architecture is a strong candidate to achieve this. In the SDTN, the software-defined networking and the networkf function virtualization (SDN/NFV) plays a key role in integrating legacy network services into the newly-deploying network. This paper proposes an SDTN architecture and presents an example of its deployment in a mobile network evolution scenario in which 3G mobile services are integrated into a 4G network. The unified mobility management, in which 3G mobile services are integrated into a 4G access networks based on SDN/NFV is described. The network nodes for legacy mobility management services are virtualized at the control plane and accommodated into the SDTN architecture. As a result, the mobility management is interoperable between the virtualized legacy network service functions and the underlying 4G network. In order to support various heterogeneous services integration into the 4G mobile network, scalable edge switches are proposed for protocol mapping between incoming heterogeneous service traffic and 4G data. The proposed SDTN approach can be applied to the future deployment of 5G networks by accommodating various pre-existing legacy services in newly-deploying networks.

Scalable wireless-optical broadband access network using reconfigurable optical backhaul and gateway selection method

We propose a scalable optical-wireless access network that is composed of reconfigurable passive optical network and wireless mesh network architectures, which is to flexibly adapt to a large scale of traffic variation in the mobile networks. The reconfigurable PON is equipped with dynamic bandwidth reallocation capability by the arrayed waveguide grating, so that it can provide improved bandwidth efficiency and graceful scalability. Furthermore, a selection method of optical-wireless integrated gateway is included to balance the network load between the two architectures. The proposed network can enhance the network capacity and decrease the congestion probability of optical-wireless access network.

Mobile flow-aware management for mobility and QoS support in mobile networks

Mobility is the most important feature of a mobile communication system. Moreover, as the volume of mobile traffic consisting of video, voice, and data is rapidly expanding, the challenge rests with the mobile transport network which must deliver the data traffic to mobile devices without degrading the service quality. In this paper we proposed a flow-aware QoS and mobility management scheme for IP-based mobile wireless network. The proposed scheme consists of dynamic handoff mechanisms based on QoS requirements per flow, which is to reduce the processing overhead of the flow router while ensuring QoS guarantee to mobile flows. The performance analyses demonstrated that the proposed scheme successfully supports the mobile flow traffic delivery satisfying the QoS requirement of flows in the wireless mobile IP networks.