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Now showing 1 - 9 of 9

NAT-Aware Peer Grouping and Chunk Scheduling for Mesh-Pull P2P Live Streaming Systems
(2015)
Jia, Wen-Kang
;
Liu, Gen-Hen
;
Chen, Yaw-Chung
;
資訊工程學系
;
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.
To Call or To Be Called Behind NATs is Sensitive in Solving the Direct Connection Problem
(2011-01-01)
Ho, Cheng-Yuan
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Tseng, Chien-Chao
;
Wang, Fu-Yu
;
Wang, Jui-Tang
;
Lin, Ying-Dar
In this article, we first depict the call-role sensitivity problem in Network Address Translation (NAT) traversal, and then propose an approach to resolving the problem. The problem is whether a direct connection can be found between two peers across NATs mainly depends on the NAT type at the caller's side. We propose the extra-candidate connectivity check where both peers initiate a direct connectivity check to eliminate the effect of the call role. We have implemented the extra-candidate connectivity check and conducted experiments with 18 different NATs. Experimental results show that our approach can indeed resolve the call-role sensitivity problem, and maximize the direct connectivity rate (DCR) which is improved by 18.71% from the original scheme.
NAT-Compatibility Testbed: An Environment to Automatically Verify Direct Connection Rate
(2011-01-01)
Ho, Cheng-Yuan
;
Wang, Fu-Yu
;
Tseng, Chien-Chao
;
Lin, Ying-Dar
;
資訊工程學系
In this article, an NAT-compatibility testbed is designed to automatically conduct the repeated experiments, collect the test results, and verify the direct connection rate (DCR) of any NAT traversal programs. Achieving a high DCR is important because using relays may unnecessarily increase the bandwidth cost, processing load of the relay servers, and the end-to-end packet delay. The NAT-compatibility testbed is constructed with 4 components: two peers, an automatic execution mechanism, NAT devices, and signaling/intermediate servers such as STUN, TURN, and SIP. It is also called the fully meshed testbed because the test result of all NAT combinations is a square. It measures the DCR of ICE, KeyStone, and PJNATH as 53.7%, 59.87%, and 50.93%, respectively. Experimental results show that asymmetric and unexpected direct connectivity check results occur in the real Internet. In order to enhance NAT traversal capability, the findings, like "port prediction" and "call-role sensitivity problem," are also described in the experimental results.
Can: A context-aware NAT traversal scheme
(2013-07-01)
Tseng, Chien-Chao
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Lin, Chia-Liang
;
Yen, Li-Hsing
;
Liu, Jyun-Yan
;
Ho, Cheng-Yuan
Network Address Translation (NAT) is a technique commonly used to share one public IPv4 address among several hosts located behind a NAT device. NAT devices typically block session requests originating from outside, causing NAT traversal problem that prevents the establishment of peer-to-peer (P2P) sessions. There have been many proposals for the NAT traversal problem. However, existing methods induce high connectivity check delay and resource demand when finding a communicating path, calling for a routine that determines the path best suited for a given pair of communicating peers. This study proposes CAN, a Context-Aware NAT traversal scheme which gathers and exchanges network-context information to find the most appropriate path for two communicating peers behind NAT devices. We have implemented CAN and conducted extensive experiments with off-the-shelf NAT devices to compare the performance of CAN with Interactivity Connectivity Establishment (ICE), the most acknowledged approach to creating a session across NATs. Experimental results show that CAN outperforms ICE in terms of direct communication ratio, connectivity check delay and message overload when checking connectivity. (c) 2013 Elsevier Ltd. All rights reserved.
Tunneling IPv6 through NAT with Teredo mechanism
(2005)
Huang, SM
;
Wu, Q
;
Lin, YB
;
資訊工程學系
;
Department of Computer Science
Teredo is a service that enables hosts located behind one or more IPv4 NATs to obtain IPv6 connectivity by tunneling packets over IPv4 UDP Under the national IPv6 deployment project in Taiwan, we developed the first Linux-based Teredo service in 2003. In this paper we explain how IPv6 candidates located behind NATs can enlist the help of "Teredo servers" and "Teredo relays" to learn their "global addresses" and to obtain connectivity, and how clients, servers and relays can be organized in Teredo networks. We also describe in details our strategies for implementing Teredo server and Teredo relay under Linux, and show the performance of different Teredo implementations in public domain.
Enhancing teredo IPv6 tunneling to traverse the symmetric NAT
(2006-05-01)
Huang, SM
;
Wu, Q
;
Lin, YB
;
資訊工程學系
;
Department of Computer Science
By tunneling IPv6 packets over IPv4 UDP, Teredo supports IPv4/IPv6 dual-stack nodes in private IPv4 networks behind Network Address Translation (NAT) to access IPv6 networks. However, the current Teredo protocol does not work with symmetric NAT. This letter proposes SymTeredo, an extension of Teredo with capability to traverse the symmetric NAT. Our extension preserves the Teredo architecture, and offers backward compatibility with the original Teredo protocol.
SIP mobility and IPv4/IPv6 dual-stack supports in 3G IP multimedia subsystem
(2006-08-01)
Huang, Shiang-Ming
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Wu, Quincy
;
Lin, Yi-Bing
;
Yeh, Che-Hua
;
資訊工程學系
In the Universal Mobile Telecommunications System (UNITS), session initiation protocol (SIP) and IPv6 are the default protocols for IP multimedia core network subsystem (IMS). However, a user equipment (UE) may not be allowed to roam or hand off from UNITS to a private-lPv4 GPRS network. In this paper, we utilize SIP mobility and an automatic IPv6 tunneling mechanism, called Teredo, to support roaming/handoff of a UE between different networks. We have developed the first non-commercial Linux-based Teredo mechanism, and compared our solution with other Teredo implementations in the public domain. Our study indicates that our solution can reduce the tunneling overhead and transmission delay over two other implementations by 44-74%. Copyright (C) 2006 John Wiley & Sons, Ltd.
A network address translation approach to the inbound session problem in private networks
(2007-02-01)
Hsieh, Ming-Deng
;
Chang, Hung-Chun
;
Tseng, Chien-Chao
;
Wang, Tsan-Pin
;
資訊工程學系
This paper proposes a Dynamic-Configurable NAT (DCNAT) approach to the inbound session problem for private networks behind NAT routers. DCNAT is a port-based NAT scheme that adopts a registration procedure for a host to register a session with a DCNAT router before originating a communication session to a host behind the DCNAT router. With the registration procedure, the DCNAT router can create NAT binding entries dynamically for address: port translation before the inbound session starts. Furthermore the dynamic creation of NAT binding entries makes DCNAT very flexible in supporting inbound accesses to a large number of services opened dynamically by the private nodes behind an NAT router. Although DCNAT requires minor modification to the originating host and the NAT router, it is highly suitable for proxy-based applications, such as web browsing, or instant message delivery.
A Survey of NAT Behavior Discovery in VoIP Applications
(2011-03-01)
Hunag, Shiang-Ming
;
Wu, Quincy
;
資訊工程學系
;
Department of Computer Science
Because of the foreseeing depletion of Internet Protocol (IP) addresses, Network Address Translation (NAT) is ubiquitously deployed to allow hosts to connect to the Internet through a single shared public IP address, which is a popular approach in deploying wireless local area network (WLAN). Although NAT proves to work well with traditional client/server applications, its existence and non-standard behaviors are the major problem which cripples voice over IP (VoIP) applications. In addition to some efforts which attempt to devise complicated protocols to tackle all NAT varieties, there are also efforts in Internet communities trying to standardize the behaviors of NAT. Therefore, it becomes crucial for a network device to discover the existence of NAT in its subnet and to determine the NAT behaviors, so that it can choose the optimal NAT traversal mechanisms to apply. In this paper, we surveyed the divergent NAT behaviors and then proposed a simplified NAT behavior discovery approach which is more suitable for VoIP applications. The proposed approach can reduce the call establishment time of VoIP applications, which is useful in scenarios where VoIP devices are administrated within a specific domain, e.g., 3G cellular networks.

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🏛️國立陽明交通大學機構典藏

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