Modeling and analyzing the effects of firewalls and NATs in P2P swarming systems

D'Acunto, Lucia; Meulpolder, M.; Rahman, Rameez; Pouwelse, Johan; Sips, Henk

doi:10.1109/ipdpsw.2010.5470937

Cited by 8 publications

(9 citation statements)

References 20 publications

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“…Hence, when the unconnectable peers are the majority, the connectable ones receive a lot of bandwidth from them while giving only a smaller amount of bandwidth in return. This result was already predicted in our previous work on P2P swarming systems [12]. Consequently, it is clear that the presence of unconnectable nodes severely affects the performance of P2P swarming systems, and VoD systems in particular, and must be kept into account when designing a new P2P system or protocol.…”

Section: Influence Of Unconnectable Peerssupporting

confidence: 77%

BitTorrent-like P2P approaches for VoD: A comparative study

et al. 2013

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The enormous popularity of Video on Demand (VoD) has attracted substantial research attention into the effective use of peer-to-peer (P2P) architectures to provide solutions at large-scale. In particular, the high efficiency of BitTorrent has inspired many P2P protocols for VoD. However, these protocols use different approaches to adapt the design of Bittorrent to VoD, and in most cases their performance has been evaluated separately and in limited scenarios. As a consequence, the research community still lacks a clear understanding of how these protocols compare against each other and how well each of them would work in real world conditions, where, for instance, peers have heterogeneous bandwidths, may freeride or may be located behind NAT/firewall.In this paper, we propose a simulation based methodology which aims at putting forward a common base for comparing the performance of these different protocols under a wide range of conditions. We show that, despite their considerable differences, (i) existing BitTorrent-like VoD approaches all share some characteristics, such as that their bandwidth reciprocity based methods to incentivize cooperation do not always yield an optimal overall performance. Furthermore, we demonstrate that (ii) in these protocols there is a trade-off between QoS and resilience to freeriding and malicious attacks. We also discover that, (iii) when peers doing streaming coexist with peers doing traditional file transfer, the latter actually benefit from this coexistence, at the expenses of the former. Finally, we show that (iv) early departures of peers from the system do not significantly affect the QoS de- livered, while jumping to a different position in the file has a bigger negative impact. Overall, our findings provide important implications for both VoD service providers and future system designers. On the one hand, our results can guide VoD service providers in selecting the most appropriate protocol for a given environment. On the other hand, exposing the flaws of current approaches will help researchers in improving them and/or designing better ones.

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Section: Influence Of Unconnectable Peerssupporting

confidence: 77%

BitTorrent-like P2P approaches for VoD: A comparative study

et al. 2013

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“…A very recently published paper, [16], focused on a problem quite similar to ours, and the paper appeared after we had submitted our paper. In specific, [16] proposed a bandwidth allocation scheme, which is similar in principle to our biased optimistic unchoke scheme but is developed independently.…”

Section: Bittorrent and Related Workmentioning

confidence: 96%

Optimizing BitTorrent-like peer-to-peer systems in the presence of network address translation devices

Chang

Liu

Wei

et al. 2010

Peer-to-Peer Netw. Appl.

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BitTorrent nowadays is one of the most important peer-to-peer (P2P) file-sharing applications on the Internet, and it has also inspired many other P2P applications such as live or on-demand video streaming services. On the other hand, Network Address Translation (NAT) has become pervasive in almost all networking scenarios, from residential Internet access to enterprise networks. Despite the effort of NAT traversal, it is still very likely that P2P applications cannot receive incoming connection requests properly if they are behind NAT. To quantify the performance impact of NAT on BitTorrent-like P2P systems, we have created and validated a detailed but tractable mathematical model. We have also proposed and briefly examined a simple but effective strategy to mitigate the negative impact on NAT peers. In this paper, we further extend our model to cover the proposed biased optimistic unchoke strategy, and optimize the system performance in terms of both average peer download time and system finish time. We also create a new, faster Java-based BitTorrent simulator, which is used to validate the extended model and show the optimality of the proposed strategy and its boundary conditions.

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“…In [5], D'Acunto et. al introduce an analytical model to show the impact of NATs on P2P swarming systems, and in [21] Liu and Pan analyse the performance of bittorrentlike systems in private networks.…”

Section: Related Workmentioning

confidence: 99%

Gozar: NAT-Friendly Peer Sampling with One-Hop Distributed NAT Traversal

Payberah

Dowling

Haridi

2011

Lecture Notes in Computer Science

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Abstract. Gossip-based peer sampling protocols have been widely used as a building block for many large-scale distributed applications. However, Network Address Translation gateways (NATs) cause most existing gossiping protocols to break down, as nodes cannot establish direct connections to nodes behind NATs (private nodes). In addition, most of the existing NAT traversal algorithms for establishing connectivity to private nodes rely on third party servers running at a well-known, public IP addresses. In this paper, we present Gozar, a gossip-based peer sampling service that: (i) provides uniform random samples in the presence of NATs, and (ii) enables direct connectivity to sampled nodes using a fully distributed NAT traversal service, where connection messages require only a single hop to connect to private nodes. We show in simulation that Gozar preserves the randomness properties of a gossip-based peer sampling service. We show the robustness of Gozar when a large fraction of nodes reside behind NATs and also in catastrophic failure scenarios. For example, if 80% of nodes are behind NATs, and 80% of the nodes fail, more than 92% of the remaining nodes stay connected. In addition, we compare Gozar with existing NAT-friendly gossip-based peer sampling services, Nylon and ARRG. We show that Gozar is the only system that supports one-hop NAT traversal, and its overhead is roughly half of Nylon's.

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Modeling and analyzing the effects of firewalls and NATs in P2P swarming systems

Cited by 8 publications

References 20 publications

BitTorrent-like P2P approaches for VoD: A comparative study

BitTorrent-like P2P approaches for VoD: A comparative study

Optimizing BitTorrent-like peer-to-peer systems in the presence of network address translation devices

Gozar: NAT-Friendly Peer Sampling with One-Hop Distributed NAT Traversal

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