Jongtae Song

Overview of ITU-T NGN QoS Control

This article presents an overview of standards activities defining the QoS control architecture. Several standards bodies define the QoS control architectures based on their scope of work. This article first reviews the QoS control architectures defined in the standards bodies such as Cable Lab, DSL Forum, MSF, ETSI, and ITU-T. ITU-T NGN architecture provides the generic framework to cover the results of each standards body. Other architectures focus on solving specific problems. We explain in more detail the ITU-T QoS control architecture defined in resource and admission control functions (RACF) and discuss future standards developments.

DiffProbe: one way delay measurement for asynchronous network and control mechanism in BcN architecture

Recently NGN standard organizations provide significant effort to implement the QoS guaranteed service in the IP based packet switching network. The NGN architecture assumes the admission control for all the premium service and monitoring the service performance to meet the QoS requirement. In Korea, broadband convergence network (BcN) architecture has been developed. BcN strategy is delivering NGN solution by converging different types of services. The service reliability and performance of BcN is maintained by OAM over virtual switched path (VSP). However, no clear solution for monitoring the delay performance network is available for asynchronous packet switching network. This paper presents the BcN architecture and introduces the performance monitoring and control algorithm for packet switching network. First part of the paper presents BcN architecture in both transport and control plane. The second part introduces a delay measurement algorithm designed for BcN network called DiffProbe (differentiated probe). DiffProbe is OAM based delay measurement algorithm that can be used for delay measurement in asynchronous transport network where the clock synchronization is not available. Network control strategy using DiffProbe is also presented. Based on the simulation result, DiffProbe captures the delay dynamics in high load condition

Performance Monitoring for Multimedia Traffic using Differentiated Probe (DiffProbe)

Guaranteeing end-to-end QoS for multimedia traffic in the IP transport network is a challenging issue. Monitoring the one way delay of the multimedia traffic is necessary but no clear solution for the performance monitoring in the core network exists. In the previous work, we introduced an one-way delay monitoring mechanism called DiffProbe. We introduced the basic concept and the implementation details in the MPLS core network. In this paper, we provided an analytical model of the scheme and investigated the performance of the proposed delay measurement mechanism. We evaluate the accuracy of the delay measurement mechanism and the efficiency of the control mechanism with the simulation. The numerical result shows that our proposed algorithm captures the delay performance of the real traffic when the traffic load is high.

Review on the operation, administration, and maintenance (OAM) of BcN

This paper briefly reviews ITU-T recommendations associated with multi protocol label switch (MPLS) and Ethernet operation, administration, and maintenance (OAM). The broadband convergence network (BcN) architecture with a centralized network controller is introduced. An aggregation structure employing Ethernet, MPLS, and time division multiplexing (TDM) signal is presented for the BcN. A physical link failure scenario is examined to investigate how the maintenance signal is propagated between different layers.

Seamless and Secure service Framework using multiple network interface terminal

In this paper, we propose a Seamless and Secure service Framework (SSF) which guarantees secure association between users terminal and safety critical system such as payment gateway by exploiting both user information and network information. Despite the leaks of personal sensitive information, SSF provides very safe service environment in wired and wireless convergence network that vertical handover happens frequently.

Integrated mobility control mechanism in next generation network

This paper presents a seamless handover mechanism. First, we proposed a host based layer 2 handover mechanism. The proposed algorithm is based on the API defined in MIH (Media Independent Handover) standard. By distributing the key intelligence to the mobile terminal, control overhead in the network side can be reduced. The principle of our mechanism is to put intelligence in the mobile terminal while the transport and control function of the network remains simple. For the HO support in the wide area, we also proposed HO mechanism that uses L2, L3, and application level handover capability. The integrated HO algorithm is based on the host based L2 HO algorithm. By using the mobility server as the pre-authorization controller, we can achieve fast handover.

Philosophy & key design principles of BcN as an enhanced NGN

Existing Internet has problem in many areas such as reliability, service availability, and manageability. Active research has been done to solve this problem. In Korea, BcN was developed to solve the well known Internet problem and to achieve the fixed-mobile convergence services. This paper explains the philosophy and design principles of BcN architecture. We first explains the background of BcN activities and its key result of BcN. We then also introduce the design principle of BcN architecture. We also present the overview of the BcN architecture and briefly describe the issues and our approaches.

Delay bounds in tree networks with DiffServ architecture

We investigate the end-to-end delay bounds in large scale networks with Differentiated services (DiffServ) architecture. It has been generally believed that networks with DiffServ architectures can guarantee the end-to-end delay for packets of the highest priority class, only in lightly utilized cases. We focus on tree networks with DiffServ architecture and obtain a closed formula for delay bounds for such networks. We further show that, in tree networks with DiffServ architecture, the delay bounds for highest priority packets exist regardless of the level of network utilization. These bounds are quadratically proportional to the maximum hop counts in heavily utilized networks; and are linearly proportional to the maximum hop counts in lightly utilized networks. We argue that based on these delay bounds DiffServ architecture is able to support real time applications even for a large tree network. Considering that tree networks, especially the Ethernet networks, are being adopted more than ever for access networks and for provider networks as well, this conclusion is quite encouraging for real-time applications. Throughout the paper we use Latency-Rate (LR) server model, with which it has been proved that First In First Out (FIFO) and Strict Priority schedulers are LR servers to each flows in certain conditions.

Congestion detection algorithm using DiffProbe

Recently NGN standard activity is going on to provide the end-to-end QoS guarantee in the IP transport network. However, monitoring the one way delay performance in the packet network has no clear solution. In the previous work [1], we introduced an one-way delay performance monitoring mechanism called DiffProbe. We introduced the basic concept and the implementation details in the MPLS core network. In [12], we provided an analytical mode of the scheme and investigated the performance of the propose delay measurement mechanism. In this paper, we propose a congestion detecting mechanism. The numerical result shows that our simple proposed congestion detection algorithm can detect the network congestion efficiently.

Review on the Operation, Administration and Maintenance (OAM) of BcN

The BcN architecture of VPWS is introduced as a service model. The network elements forming the BcN data plane and a centralized controller forming the BcN control plane functionality are briefly described. A mapping architecture which transports the VPWS signal is presented. We examine the propagation of the maintenance signal under the network failure condition. The main purpose of this architecture is to find out the relationship between the maintenance signals in each layer. Finally, we briefly review the MPLS OAM ITU-T Rec. Y.1711 and Ethernet OAM being recommended in ITU-T Rec. Y.1731.