Browsing by Author "Jia, Wen-Kang"

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A conflict-insensitive NATed roaming framework using NAToD for proxy mobile IPv4 in WLANs
(2013-07-01)
Jia, Wen-Kang
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Chen, Yaw-Chung
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資訊工程學系
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Department of Computer Science
Providing efficient mobility management in the current Internet is increasingly important due to the quick growth of wireless mobile users. The emerging Proxy Mobile IPv4 (PMIPv4) technique brings a possible solution for that purpose. Since NAT function is widely adopted in IPv4 environment nowadays because of lacking IPv4 addresses, the PMIPv4 interoperating with NAT must be considered. Unfortunately, owing to the possible conflict of private IP address, we encounter a problem in broadcasted point-to-multipoint wireless networks such as IEEE 802.11 networks. To address this issue, we proposed a novel Network Address Translation on Demand (NAToD) scheme, which can well interoperate with the PMIPv4 solution. With our scheme, single public IPv4 addresses can be shared by multiple mobile nodes in both home and foreign networks, low-latency handoff can be achieved, deployment cost can be reduced, and software upgrade can be avoided for mobile nodes in wireless LANs. Our work allows mobile users in WLAN to access Internet based on the advantages of both PMIPv4 and NAT.
A cross-layer error correction scheme based on multiple-CRC in OFDM/OFDMA wireless networks
(2013)
Chen, Chia-Yao
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Jia, Wen-Kang
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Chen, Yaw-Chung
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資訊工程學系
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Department of Computer Science
The orthogonal frequency division multiplexing access (OFDM/OFDMA) based wireless transmission technology has been widely deployed in recent years. The frame check sequence (FCS) scheme is employed to enhance the reliability of OFDM/OFDMA systems. Since the padding overhead cannot be effectively avoided in OFDM/OFDMA when medium access control frames are encapsulated, we propose a novel cyclic redundancy check based error correction scheme by utilizing the padding space to carry extra segmented FCS information as much as possible; compared with the legacy FCS scheme, our approach greatly enhance the error detection and correction upon the first retransmission (second transmission). A significant performance improvement based on the simulation results is also demonstrated.
A Cut-through Scheduling for Delay Optimization in TD-LTE Relay Enhanced Networks
(2017-01-01)
Jia, Wen-Kang
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Chen, Yaw-Chung
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資訊工程學系
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Department of Computer Science
The relaying is the most important feature as a practical solution in LTE technologies to improve performance and to extend coverage. This paper contributes to the performance on cut-through forwarding mode in relaying framework for applying in TD-LTE standard referred to as 3GPP release 10 and above, it provides lower forwarding latency per hop by rescheduling the alignment of sub-frame duration between each superordinate relay node and subordinate relay node. We demonstrate a significant performance improvement through simulation, the results show that the proposed scheme features lower forwarding latencies for both uplink and downlink in terms of one-way end-to-end delay as compared to legacy synchronous relaying of the relay enhanced TD-LTE networks.
A Hardware-based Preemptive Dynamic Bandwidth Allocation Mechanism for Real-time Applications in EPONs
(2012-01-01)
Jia, Wen-Kang
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Yang, Yuan-Rung
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Chen, Yaw-Chung
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資訊工程學系
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Department of Computer Science
with the emergence of Ethernet as a convergence layer in access network, Ethernet Passive Optical Network (EPON) has evolved. It is being considered as a promising solution to the "last mile" problem in next-generation broadband access network. An EPON is a point-to-multipoint tree topology, which carries 802.3 Ethernet frames between an optical line terminal (OLT) and multiple optical network units (ONUs) via a passive optical splitter. The multi-point control protocol (MPCP) for medium access control (MAC) in an EPON. In this paper, we investigate design issues for access networks based on passive optical network technology, and we present a preemptive transmission mechanism that works on MAC and PHY layer of OLT and ONU components. We conduct detailed simulation experiments to study the performance and validate the effectiveness. The proposed novel scheme effectively reduces the frame queuing delay as well as jitter, so as to enhance system throughput.
A Novel Optical Code-Based Label Switching Architecture for WDM Packet Switched Networks
(2010-12-01)
Wang, Zhao-Wei
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Liang, Man-Gui
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Jia, Wen-Kang
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Chen, Yaw-Chung
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資訊工程學系
To cope with ever-increasing traffic demands in transport networks, all-optical switching is currently perceived as a solution to remove bottlenecks imposed by O/E/O conversions. Optical label switching accomplishes packet switching using the optical-labels. It simplifies the design of switching devices in the optical domain and speeds up packet forwarding significantly. In this paper, we propose a novel design of optical switches, and present a performance analysis to show its in-depth behavior. The analysis results demonstrate the effectiveness of the proposed switching architecture.
A Novel Optical Code-Based Label Switching Architecture for WDM Packet Switched Networks
(2010-12-01)
Wang, Zhao-Wei
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Liang, Man-Gui
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Jia, Wen-Kang
;
Chen, Yaw-Chung
;
資訊工程學系
To cope with ever-increasing traffic demands in transport networks, all-optical switching is currently perceived as a solution to remove bottlenecks imposed by O/E/O conversions. Optical label switching accomplishes packet switching using the optical-labels. It simplifies the design of switching devices in the optical domain and speeds up packet forwarding significantly. In this paper, we propose a novel design of optical switches, and present a performance analysis to show its in-depth behavior. The analysis results demonstrate the effectiveness of the proposed switching architecture.
A Redundancy-Free Reliable Multicast in Wireless Multi-hop Relay Networks
(2011)
Chen, Chia-Yao
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Jia, Wen-Kang
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Yang, Yuan-Rung
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Chen, Yaw-Chung
;
資訊工程學系
The Orthogonal Frequency Division Multiplexing Access (OFDM-based) wireless transmission technology is widely deployed nowadays, and Frame Check Sequence (FCS) scheme is used to enhance the reliability of OFDM-based systems. Since the padding overhead cannot be effectively avoided in OFDM-based system when MAC frames are encapsulated, we propose a novel CRC based error correction scheme by utilizing the frame padding overhead to carry extra segmented FCS information as much as possible; compared with legacy FCS scheme, our approach achieves a significant improvement in error detection and correction for the multicast frame in transparent mode multi-hop relay network. We demonstrate a significant performance improvement based on the mathematical analysis.
A Scalable Multicast Source Routing Architecture for Data Center Networks
(2014-01-01)
Jia, Wen-Kang
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資訊工程學系
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Department of Computer Science
This paper introduces a new scalable, efficient and stateless source routing scheme to ensure that unified unicast and multicast packets can be delivered in the Data Center Networks (DCNs). This scheme, called Code-Oriented eXplicit multicast (COXcast), is based on unicast and eXplicit multicast (Xcast). It constructs the unicast path and multicast tree by encoding the corresponding output port bitmap of each intermediate node. Using a common identifier and a node-specific key, so packets can be self-routed to multiple receivers without requiring header modification. In addition, intermediate switches/routers on the path/tree can be stateless. Compared to traditional source-based unicasting and explicit-based multicasting schemes, COXcast has lowered the processing cost, protocol overhead and delivery latency, while simplifying the deployment and management of a large number of medium-scale multicast groups, especially when applied to large-scale DCNs.
A Scalable Source Multipath Routing Architecture for Datacenter Networks
(2015)
Jia, Wen-Kang
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Liu, Gen-Hen
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Chen, Yaw-Chung
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資訊工程學系
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Department of Computer Science
The continuous growth in traffic volumes on modern Data Center Networks (DCNs) can be classified into either delay-or throughput-sensitive applications. In order to providing quality delivery to such applications, it is important that multipath routing and/or forwarding can be supported in the DCNs. However, some inherent problems of multipath forwarding have not been totally solved by existing solutions. Aiming to balance all these requirements for the multipath DCNs, we propose a novel solution-Code-Oriented eXplicit MultiPath (COXMP) scheme which evenly distributes traffic along multiple paths, resulting in better network throughput, delay, jitter, and resilience. The simulation results show that COXMP outperforms existing solutions and achieves a reasonable tradeoff between scalability and overhead.
A Teletraffic Perspective on Relay-Node Selection Strategy in VoP2P System
(2009)
Jia, Wen-Kang
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Chen, Yaw-Chung
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資訊工程學系
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Department of Computer Science
This paper gives a theoretical approach to modeling and simulating the Grade of Service (GoS) of Voice over Peer-to-Peer Session Initiation Protocol system which is created based on various teletraffic parameters. VoP2P features a particular service characteristic due to its different GoS models originated from circuit switched telephone networks. Especially, most voice session in VoP2P is indirectly connected because peer-nodes usually locate behind NATs. This situation forces peer-node to select one or more relay-node for establishing sessions. However, the relay-node is a constrained resource because every relay-node can only support very limited relay services in VoP2P network. There are two strategies, the S(2)RS (Staged Single-Relay Strategy) and MRS (Multi-Relay Strategy), to solve the relay-node issue. We adopt three new parameters in VoP2P call-loss models, the first is callee-attendance rate, which is due to the characteristic of destination peer-nodes with a lower attendance probability; the second is call-blocking rate, which is a traditional definition just because the relay-node reaches the limitation of resource; the third is handoff-dropping rate (aka handoff-loss rate), which is caused by the relay-node being removed frequently. The simulation results provide useful reference in the study of teletraffic of VoP2P system.
A unified MIPv6 and PMIPv6 route optimization scheme for heterogeneous mobility management domains
(2014-12-24)
Jia, Wen-Kang
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資訊工程學系
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Department of Computer Science
Nowadays more and more wireless users are on move while accessing the Internet, and providing mobility support in IP networks has been a long-standing challenge. Client-based Mobile IPv6 (MIPv6) is the most widely known mobility management scheme, and fast emerging Proxy-based Mobile IPv6 (PMIPv6) scheme offers an alternative. However, some inherent problems such as route optimization in these schemes have not been totally solved. Although various proposals tried to tackle the route optimization problem, none of them has achieved a satisfactory success. Furthermore, most of them are not a comprehensive solution for coexisting MIPv6/PMIPv6 mobility environments. In this paper, we propose a unified approach to Route Optimization (RO) scheme based on a simplified MIPv6 Return Routability Procedure (RRP) protocol, called Traffic Driven Pseudo Binding Update (TDPBU), which can significantly improve the overall performance of mobility management schemes. Our proposed scheme can ensure immediate route optimization, regardless the heterogeneous MIPv6/PMIPv6 environment in which the MNs reside. Simulation results show that TDPBU can improve the performance in terms of the end-to-end latency, signaling cost, throughput, route optimization latency, route optimization blocking rate, and power consumption compared to original MIPv6 with RRP mechanism. Besides, the deployment cost and software complexity of both network entities and clients, are expected reduction. (C) 2014 Elsevier B.V. All rights reserved.
A Unified Unicast and Multicast Routing and Forwarding Algorithm for Software-Defined Datacenter Networks
(2013-12-01)
Jia, Wen-Kang
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Wang, Li-Chun
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電機工程學系
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Department of Electrical and Computer Engineering
In this article, we consider a scalability problem associated with software-defined datacenter, of which the unicast/multicast routing states is proven to be NP-complete. We introduce an efficient multiple membership query algorithm, called Scalar-pair Vectors Routing and Forwarding (SVRF), based on the prime theory such as Chinese Remainder Theorem (CRT). Our proposed algorithm simply calculates corresponding output ports of each multicast group by dividing a common scalar-pair with a group-specific key, within pseudo-polynomial time. The result is then used to make a forwarding decision within few cycles through a hardware accelerator. Compared to Bloom filter, our algorithm can achieve remarkable performance in terms of memory consumption, processing time, hardware cost, and 100% delivery accuracy, while applying for a large number of large-scale distinct flows (including unicast and multicast) in a large-scale datacenter networks. Our work may be applied to various research areas of computer science and networking.
ALEX: An Arithmetic-based Unified Unicast and Multicast Routing for MANETs
(2014)
Jia, Wen-Kang
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Chen, Chia-Yao
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Chen, Yaw-Chung
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資訊工程學系
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Department of Computer Science
Explicit multicasting protocols such as Differential Destination Multicast (DDM) in MANETs have been retaining advantages of traditional approach while eliminating their shortcomings especially for small-group applications. However, they still have some drawbacks especially in the group size limitation. In this work we discussed a new unified unicast and multicast routing scheme called Arithmetic Labeled EXplicit (ALEX) Multicast Routing based on arithmetic encoding of on tree node keys and recursive unicast for MANETs. Our scheme constructs the multicast tree by decoding the bitmap of its output ports for next hops in the forwarding path using a common Multicast Channel Mentifier (MCID) and a node-specific key, so that multicast packets can be self-routed to multiple receivers without requiring header modification, and intermediate nodes on the multicast mesh will be stateless. In addition to scaling up the multicast group size, our scheme can reduce the processing complexity, control overhead and delivery latency comparing to the existing works. The simulation results indicated that our proposed scheme achieves a remarkable improvement in scalability while simplifying the deployment and management for a large number of medium-size multicast groups in MANETs.
Analysis of Optical Code-Based Label Switching
(2010-01-01)
Wang, Zhao-Wei
;
Liang, Man-Gui
;
Jia, Wen-Kang
;
Chen, Yaw-Chung
;
資訊工程學系
To cope with ever-increasing traffic demands in transport networks, all-optical switching is currently perceived as a solution to remove bottlenecks imposed by O/E/O conversions. Optical label switching offers packet switching using the optical-labels. It simplifies the design of switching devices in the optical domain and speeds up packet forwarding significantly. In this paper, we propose a novel design for optical switch, and present a performance analysis to provide deeper insight in its behavior. The analysis results show the effectiveness of the proposed switch technology.
Challenge and solutions of NAT traversal for ubiquitous and pervasive applications on the Internet
(2009-10-01)
Chen, Yaw-Chung
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Jia, Wen-Kang
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資訊工程學系
;
Department of Computer Science
Network Address Translator (NAT) has brought up many changes and opportunities to the Internet. How do the ubiquitous and pervasive applications coexist with NAT and interoperate with each other? In this article, we discuss the essence of NAT sensitive applications as well as the challenge and response for various NAT traversal solutions. All questions pointed to redesign a new NAT framework with a major change to accommodate NAT problems all at once. We introduce a novel next generation NAT (NATng) framework, which consists of a Bi-directional NAT (BNAT) and a Domain Name System Application Level Gateway (DNS_ALG) with a Border Network Address Translator Control Protocol (BNATCP) function to control all BNATs. The above components coordinate and provide bidirectional access capability between intranet and Internet, so all private hosts can be addressed via Fully Qualified Domain Name (FQDN). Logistically, NATng extends the IPv4 address space from 2(32) to 2(48) or even more. It features high potential to solve the problems for ubiquitous and pervasive applications which may encounter IPv4 address exhaustion on the current Internet. (C) 2009 Elsevier Inc. All rights reserved.
Deploying Circuit Emulation Services (CES) Over EPON Using Preemptive Priority Medium Access Controller
(2013-03-01)
Jia, Wen-Kang
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Chen, Yaw-Chung
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資訊工程學系
;
Department of Computer Science
Circuit Emulation Services (CES) technology has emerged as an option to mitigate traditional Time Division Multiplexing (TDM) circuits supporting legacy applications across managed packet networks and the Ethernet Passive Optical Network (EPON) is becoming a major technology for pervasive access. The primary benefits of CES over EPON (CESoEPON) are the low cost and simplicity of deployment to support all types of legacy TDM applications across EPONs. Thus, the QoS-guarantee for highly delay-sensitive services on EPONs could be enhanced. This paper investigates a preemptive priority transmission technique that works on MAC and PHY layer of downstream EPONs. The proposed novel scheme effectively reduces the frame queuing delay as well as jitter, so as to enhance precise time synchronization in EPONs. Through simulation experiments, we show that the proposed scheme achieves superior and precise QoS control compared to existing non-preemptive priority methods. A feasible implementation of the proposed solution is also addressed. Finally, we present a general conclusion of the paper as well as address the pros and cons for practical deployment in future works.
Design and Development of Revolved 5G Core Networks Based on Lower-Layer Software-Defined and Upper-Layer Virtualized Approaches
(2018-01-01)
Jia, Wen-Kang
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Chen, Yaw-Chung
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Zheng, Yun
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Ying, Ruolan
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資訊工程學系
5G EPC over Network Functions Virtualization (NFV) complemented with Software Defined Networking (SDN) framework is envisioned to be a novel paradigm of network architecture that supports a variety of access technologies and solves growth challenges and requirements such as seamless mobility management. Using cloud and virtualization, it manages and orchestrates the execution of mobile core servers on virtual machines. SDN can be used to segregate the network allowing multiple virtual mobile networks to co-exist on a physical datacenter network. This design is free of redundant functionality and inter-node interfaces that increase costs and reduce performance in hardware-based packet cores. With proposed vEPC (Virtualized Evolved Packet Core) framework we could construct a network of any-size with linear performance scaling on general-purpose servers for cost-effective business growth.
Joint Resource Allocation for Multi-homing and Single-network Users in Heterogeneous Cognitive Radio Networks
(2017-01-01)
Chen, Feng
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Fu, Mingjian
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Jia, Wen-Kang
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交大名義發表
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National Chiao Tung University
This paper investigates the resource allocation problem in heterogeneous cognitive radio networks (HCRNs). In this paper, two types of users, i.e., multi-homing and single-network cognitive radio users (CRUs), are considered to coexist in HCRNs. Multi-homing CRUs can access multiple networks simultaneously, while single-network CRUs can be served by only one network at a time. With the aim of maximizing the system capacity of HCRNs, the resource allocation problem is formulated as a joint multi-dimension optimization problem which includes network selection, bandwidth and power allocation for both multi-homing and single-network CRUs. However, the joint multi-dimension optimization leads the problem to be non-convex and NP-hard. To solve the problem efficiently, continuous relaxation is performed firstly, and next a near-optimal solution using Lagrangian dual decomposition and Karush-Kuhn-Tucker (KKT) conditions is proposed in this paper. Numerical results show the proposed algorithm improves the system capacity significantly compared to the traditional ones.
MToS: Multi-Tenant Network over Software Defined Networking
(2019-01-01)
Jia, Wen-Kang
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Chen, Yaw-Chung
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Lin, Johanes
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資訊工程學系
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Department of Computer Science
MToS, a multi-tenant network service is designed and implemented under Software-Defined Network (SDN) environment. One of the solutions to establish multi-tenant network in non-SDN environment is Multi-Protocol Label Switching Virtual Private Network that involves numerous and complicated protocols to be configured prior to the establishment of multi-tenant network. With SDN, it opens new opportunities to create multi-tenant networks that are less complicated, more automated, and lower implementation cost via SDN commodity devices. MToS categorizes OpenFlow switches into three hierarchies, where matching fields and actions in flow entries are different depending on the switch hierarchy. Therefore, traffic forwarding can be scalable. MToS provides tenant isolation through dedicate flow table associated with each tenant, and tenant MAC address as the identifier which is used in flow table redirection and packet header modification. Traffic forwarding between Edge switches is achieved through Edge MAC address as the identifier which is used in packet header modification, and Edge switch serves as ARP Proxy for tenant end hosts. Comparing to MPLS VPN, MToS only requires essential information about tenants to construct a multi-tenant network. By taking advantage of SDN centralized global network information, MToS adds automations of IP address management and shortest path routes calculation. MToS is developed based upon OpenFlow version 1.3, and implemented in Python and runs on top of Ryu SDN framework.
NAT-Aware Peer Grouping and Chunk Scheduling for Mesh-Pull P2P Live Streaming Systems
(2015)
Jia, Wen-Kang
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Liu, Gen-Hen
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Chen, Yaw-Chung
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資訊工程學系
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Department of Computer Science
Live streaming (a.k.a. Internet Protocol Television (IPTV)) services have been popularly deployed on the Internet. Traditionally, IPTV service provider adopted client-server architecture. However, when the client population grows up to a certain amount, it usually faces the scalability and cost-effective problems. Fortunately, the development of Peer to Peer (P2P) content sharing application has proved that the P2P paradigm is an efficient solution to deliver many kinds of content over the Internet. P2P IPTV services may face the problem that there are more and more Network Address Translator (NAT) users, and peers behind NAT (NATed peer) cannot directly deliver its streaming data to other NATed peers. This situation easily leads to the so-called free rider problem. In this paper, we propose a grouping and scheduling scheme to increase the share rate of NATed peers. By restricting transmission connectivity of those peers with public IP address and properly arrange data chunks delivery, we could allow NATed peer to contribute more data on the overlay network. Simulation results show that proposed scheme can improve the performance in terms of the share rate and video playback quality compared to original NAT traversal mechanism. Besides, the deployment complexity of both P2P IPTV operators and peers, are expected reduction.