Boyoung Rhee

Overlay Multicast Architecture Supporting QoS over NGN

NGN is a communication network which can make use of multiple broadband and QoS-enabled transport technologies. One of the main service issues over NGN is a multimedia service, like IPTV and VOD, which is using multicast technology. And overlay multicast technology is one of the promising solutions instead of general multicast technology which has a few problems, and supports flexibility and scalability for multicast services. Also, the main controversial topic in NGN and overlay multicast at present is QoS. In the present paper, we designed an agent in each receivers network and a manager which is in a source network and which manages the whole multicast network. Both of them are communicating with each other and applying resource policies to their multicast network. This mechanism enables overlay multicast to support QoS, focusing on RACF in NGN architecture.

Design and implementation for reducing zapping time of IPTV over overlay network

The QoE improvement provides improvement in the speed of internet service. If we can reduce one second of the delay of internet service, there will be a big improvement for the QoE. There is the same situation with IPTV service. Reducing zapping time is the linchpin in the QoE of the IPTV service. The main reason of the zapping time occurrence is the latency when user joins IGMP group. The second causation is the latency of transporting video, and the third one is latency that a settop box takes to encode the video. In this paper, we mainly research how to reduce the latency when the user joins into the IGMP[2] group. In IPTV, each user must join the group according to the IGMP group. We are proposing to tie join messages of the same IPTV groups users together and after send to the server. With this way we can reduce the latency of the joining to the IGMP. In this paper, we analyzed zapping time problem about IPTV service, and we also addressed network performance and user management. We tested our solution in the overlay multicast testbed and analyzed the results of test.

Multi-session Method to Reduce Handover Latency and Data Losing in FHMIPv6

Mobile IPv6 has several defects such as overloading of nodes, loss of wireless signals, packet loss, movement problem and so forth. In this paper, we proposed a scheme to deal with F-HMIPv6 (Fast-Hierarchical Mobile IPv6) handover packet loss. With our scheme, we use the Multi-Session technology which connects among NAR, PAR and MAP to reduce the data losing during MN handover time. Data losing can be reduced mostly with our scheme.

An Overlay Multicast that Supports a Distinguished QoS Based on Service Levels and User Environments in the Next Generation Network

Next Generation Network (NGN) is a broadband network that guarantees the quality of data transfers, independent of the lower transfer media, as real-time broadcasting services that are featured as a key service of the NGN require the multicast technique. Nevertheless, the existing IP multicast contains many limitations of application. Overlay multicast IP, an alternative to IP multicast, is a network studied widely for its ability to offer effective multimedia multicast transfers through flexibility and scalability. In this paper, we designed an agent for the destination network of each receiver and a manager that manages the entire overlay multicast topology for the source network where the media server is located. The manager and agent communicate with each other to assume the role of providing services based on network resource status. In this way, we can create a multicast environment that guarantees QoS in the NGN environment, which will be based on RACF (Resource and Admission Control Functions).

Effective sensing movement of objects in ring sensor networks

A sensor uses nearby sensors to collect information and sends the information to sinks. Then, the sink forwards this collected information to users. However, if the purpose of these sensors is not to collect general data but to sense the movement of movement objects, it is difficult to sense fast moving objects with a clustering technique, which is used to collect general data. In this paper we propose a ring cluster technique that is an extended method from the basic cluster method, and this method is suitable for sensing of moving objects movement.

QoS-Adaptive Router Based on Per-Flow Management over NGN

In the present paper, we designed a specific router which provides the required level of QoS over NGN(Next Generation Network) by controlling data flows. We called this router QoS-Adaptive router, which consists of two parts, a legacy routing part and a QoS guarantee routing part. In order to provide differentiated services, QoS-Adaptive router enables data taking broad bandwidth or data requiring high-level QoS to be processed immediately and not to be affected by other services. And, we used the definition of flow for per-flow management, and assigned new service types to the flow label field of IPv6 header so as to provide differentiated services according to the packet type. By doing this, we designed a distinguishing mechanism in order to adapt to NGN that concentrates upon QoS. We built not only a small network to test QoS-Adaptive router but also a simulation environment called OMNeT++, and we could verify the performance of QoS-Adaptive router supporting QoS based on subscriber and service levels.

Design of User Bandwidth Management in Transport Layer of NGN

Current networks are evolving to NGN (Next Generation Network) which supports guaranteed quality of broadband multimedia services that are integrated with communication, broadcast and the Internet. In NGN environment should enable various services which are requiring high-level quality of service like real-time services to be provided seamlessly even though users use many kinds of communication networks and terminals. This paper proposes not only a solution for a problem that a user networks bandwidth is so insufficient that all services cannot be supported, but also a mechanism that tries to improve services efficiency for the user network over NGN by designing the user bandwidth control function, named UBCF (User Bandwidth Control Function).

Overlay Multicast Mechanism Supporting Differentiated QoS According to Service Level and User Environment over NGN

ABSTRACT NGN(Next Generation Network) is a communication network which can make use of broadband and QoS-enabled transport technologies. One of the main service issues over NGN is a multimedia service, such as IPTV, using a multicast method. And overlay multicast technology is one of the promising solutions instead of traditional multicast technology which has a few problems, and supports flexibility and scalability for multicast services. Also, the main controversial topic in NGN and overlay multicast is QoS. In the present paper, we designed an agent in each receiver’s network, and a manager which is in a source network and which manages the whole multicast network. Both of them are communicating with each other and applying resource policies to their multicast network. This mechanism enables overlay multicast to support QoS, focusing on RACF(Resource and Admission Control Functions) in NGN QoS architecture.Keywords:NGN(Next Generation Network), Overlay Multicast, QoS, Differentiated Service, Resource Management, RACF(Resource and Admission Control Functions)

Extended-RACF Mechanism of Resource Management in BcN Environment

In the aspect of the BcN, there needs to be a new method to measure performances. The ways to find it for the interworking relationship between quality measurement of BcN converge services and different measuring tool of businesses that requires service quality management and various service quality at the ends of a heterogeneous network environment. This paper is about the RACF-based BcN quality management architecture and the RACF architecture operating mechanism. Extended-RACF mechanism has been setup to efficiently run RACF- based BcN service quality management of which a quality measurement scenario has been designed.