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25 September 2010, Volume 8 Issue 3

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The whole issue of ZTE Communications September 2010, Vol. 8 No. 3

2010, 8(3):  0. 

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Special Topic

Study of the China PTN Industry Standard and Its Key Issues

Zhang Haiyi, Li Fang

2010, 8(3):  1-4. 

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In the area of carrier technologies, Packet Transport Networking (PTN) continues to attract significant research interest. Although international standards are not yet complete, China is leading the way in developing PTN equipment and network applications. General Technical Requirements for Chinese Packet Transport Networks is the PTN industry standard in China defined by China Communications Standards Association (CCSA). This article introduces the background of PTN technology and standards, then illustrates four important aspects: PTN network architecture, multi-services bearing and data transfer function, PTN network protection, and OAM architecture and functional requirements. Taking the profit motives of Chinese carriers and vendors into consideration, some key issues in PTN technology selection, network applications, and future evolution are discussed.

Standardization Progress of Packet Transport Networks

Yang Jian

2010, 8(3):  5-8. 

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Global operators are in the process of constructing next generation IP packet-switched networks, with the view of moving towards full IP-based networks. As data services increase, improvements in bandwidth, Quality of Service (QoS), Operation Administration and Maintenance (OAM), and network reliability are required. Convergence of network data transmission and network communications technology has been driven by converged IP services (including video, voice, and data), and unified multi-service load demand. Packet Transport Networking (PTN) has come into being to meet these requirements, and PTN Standards are being developing rapidly.

Several Issues in the Development of Packet Transport Networks

Jing Ruiquan

2010, 8(3):  9-12. 

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Several key issues affect the development and standardization of Packet Transport Networks (PTN) and Multiprotocol Label Switching Transport Profile (MPLS-TP). These include the end-to-end Quality of Service (QoS) mechanism, layered network architecture, introduction of layer-3 functions, and data-plane loopback functions. This paper introduces several views on the construction and maintenance of PTN, and on the requirements of PTN services. After an analysis of Traffic Engineering (TE) based on Multiprotocol Label Switching (MPLS) and Differentiated Service (DiffServ), a service-oriented end-to-end QoS guarantee mechanism is proposed. An alternative to introducing layer-3 functions into PTN is also proposed, based on PTN layered architecture defined in the available MPLS-TP standards and drafts. Requirements of data-plane loopback functions are discussed in conclusion.

Features of PBB-TE Architecture and GMPLS Control Technology

Wei Jianwen, Xie Rui, Jin Yaohui

2010, 8(3):  13-16. 

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Time Division Multiplexing (TDM) transport networks are evolving to packet-oriented, and a variety of carrier-class packet transport technologies have emerged. Provider Backbone Bridge with Traffic Engineering (PBB-TE) is a connection-oriented packet transport technology that provides good scalability and manageability, and guarantees Quality of Service (QoS). Generalized Multi-Protocol Label Switching (GMPLS) is a mature transport network control plane technology that supports multiple data planes with different switching granularity. GMPLS-controlled PBB-TE is a promising solution for Packet Transport Networks (PTN)

Ring Protection and Survivability Mechanisms for Packet Transport Networks

Lu Yueming

2010, 8(3):  17-21. 

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Packet Transport Networks (PTNs) must resolve issues in their protection and recovery mechanisms. These issues include the detection performance of Operation, Administration and Maintenance (OAM), network resource optimization, resource allocation deadlock, and resource deployment blocking. Traditional protection and recovery mechanisms cannot meet the requirements of PTN. In order to improve the protection and recovery performance, network resource use, probability of service recovery, and to decrease the probability of service blocking, this paper introduces overlapped segment shared protection, Pre-configured Multi-Cycle (P-mcycle), conflict-free algorithm, and delay restoration algorithm. Only with appropriate protection and restoration mechanisms is it possible to achieve smooth evolution from TDM networks to integrated packet-based bearer networks and all-IP services.

Service Adaptation and Label Forwarding Mechanism for MPLS-TP

Zhang Yongjun，Zhang Zhihui，Gu Wanyi

2010, 8(3):  22-26. 

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Most services borne by transport networks have been transitioned away from Time Division Multiplexing (TDM) towards IP-based. New technology is therefore required to effectively transport packet services. Multiprotocol Label Switching Transport Profile (MPLS-TP) is such a technology which is connection-oriented, capable of multiservice adaptation, and has a flexible label forwarding mechanism. This paper analyzes the characteristics of MPLS-TP, and introduces its latest standardization development. Key issues including data forwarding plane, service adaptation, and label forwarding mechanism are discussed, as well as service implementation of Virtual Private Network (VPN) based on dual-label transport. MPLS-TP applications are summarized in conclusion.

PTN Clock Synchronization Technology and Its Applications

Li Qin

2010, 8(3):  27-31. 

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Clock synchronization is an important issue for packet transport networking. Current clock synchronization technologies include synchronous Ethernet, IEEE 1588v2, and Network Time Protocol (NTP). However, individually, these technologies are beset with certain problems. Synchronization Status Message (SSM) algorithm for synchronous Ethernet standards suffers clock ring, and has difficulty tracing and counting nodes. An extended SSM algorithm can improve clock synchronization. NTP is too imprecise to meet the requirements of telecom networks, yet IEEE 1588v2 alone can lead to slow convergence time and influence time delay precision when the network is heavily loaded. ZTE therefore proposes an IEEE 1588v2 solution based on synchronous Ethernet in order to effectively raise the precision of Packet Transport Network (PTN) time synchronization.

PTN and IP-Based Mobile Backhaul

Cong Kai, Zhao Fuchuan

2010, 8(3):  32-36. 

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Packet Transport Networks (PTN) combine the advantages of packet technology and Synchronous Digital Hierarchy (SDH) technology. Taking the packet switch as its core, PTN has a high statistical multiplexing ability, which allows it to become a more efficient packet transfer service. Its strong Operation Administration and Maintenance (OAM)—similar to SDH and carrier-class security protection services—ensures efficient mobile backhaul business management and transmission quality. MPLS Transport Profile (MPLS-TP) packet transport network eliminates connectionless features, such as Penultimate Hop Popping (PHP), label merge and Equal-cost multi-path (ECMP), and is enhanced in terms of OAM, protection, and synchronization. This is ideally suited for carrying IP-based mobile backhaul services and key account services. PTN, original Multi-Service Transport Platform (MSTP), Metro Ethernet, and IP over Wave Division Multiplexing (WDM)/Optical Transport Network (OTN) of organic complexes, contribute to an "all IP" era of telecommunications services.

Research Paper

Analysis of Time Synchronization in PTN

Li Han

2010, 8(3):  37-41. 

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For Time Division Synchronous Code Division Multiple Access (TD-SCDMA) and Time Division Long Term Evolution (TD-LTE) wireless systems, using Global Positioning System (GPS) for time synchronization is problematic. In these wireless systems, GPS is costly, insecure, and difficult to deploy. Nowadays, transportation of high precision time/phase synchronization signals via fiber, and based on Precision Time Protocol (PTP) has become mainstream technology. This paper analyzes the main factors affecting time synchronization in a Packet Transport Network (PTN) adopting IEEE 1588v2. Laboratory experiments and field tests prove the feasibility of transporting high precision time synchronization signals through a PTN adopting IEEE 1588v2. A comparison is also made between different networking modes for a PTN adopting IEEE 1588v2.

Vehicular Ad-Hoc Networks:An Information-Centric Perspective

Bo Yu, Chengzhong Xu

2010, 8(3):  42-49. 

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Emerging Vehicular Ad-Hoc Networks (VANET) have the potential to improve the safety and efficiency of future highways. This paper reviews recent advances in wireless communication technologies with regard to their applications in vehicular environments. Four basic demands of future VANET applications are identified, and the research challenges in different protocol layers are summarized. Information dissemination is one of the most important aspects of VANET research. This paper also discusses the primary issues in information dissemination from an information-centric perspective, and provides two case studies. Finally, future research directions and possible starting points for new solutions are considered.

Applying Analytical Hierarchy Process to a WiMAX Performance Evaluation Model

Ronald Shiu Keung Kwan, Kim Fung Tsang

2010, 8(3):  50-55. 

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Evaluating performance of individual features of WiMAX technology is a topic of widespread discussion. Currently, there is no quantitative way of measuring WiMAX technology so that wireless operators can meet their design objectives. This paper outlines a set of design criteria for WiMAX and provides a decision-making aid that ranks the importance of criteria using Analytic Hierarchy Process (AHP). This ranking should sufficiently reflect market expectations of the relative importance of various design criteria. A model integrating AHP priorities with enhanced Data Envelopment Analysis (DEA) is the basis for formulating a technological value in simple, comparable format. A case study is provided to show how this technological value is used to evaluate a three year network deployment plan. In the future, this model could be extended to WiMAX equipment suppliers for the purpose of validating performance targets of individual criteria, and enhancing supplier roadmaps for future network development.

Development Field

Research on Convergence Network of EPON and WiMAX Based on ROF

Zhang Shu, Liu Deming, Wu Guangsheng

2010, 8(3):  56-58. 

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Convergence of optical and wireless networks is a promising development for future access network architecture. A Radio over Fiber (ROF)-based network that converges Ethernet Passive Optical Network (EPON) and Worldwide Interoperability for Microwave Access (WiMAX) technologies makes it possible to simultaneously transmit EPON baseband signals and WiMAX wireless Radio Frequency (RF) signals. This article elaborates on uplink and downlink transmission, redundancy protection, and roaming features of such a network.

Lecture Series

Cloud Computing (3)

Wang Bai, Xu Liutong

2010, 8(3):  59-64. 

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