TY - JOUR
T1 - EnhancedBit
T2 - Unleashing the potential of the unchoking policy in the BitTorrent protocol
AU - Atlidakis, V.
AU - Roussopoulos, M.
AU - Delis, A.
N1 - Funding Information:
We would like to thank the anonymous reviewers for their fruitful feedback. This work was partially funded by the iMarine EU-FP7 project and ERC Starting Grant #279237 . Part of this work appeared in the 18th International European Conference on Parallel and Distributed Computing [1] .
Funding Information:
M. Roussopoulos is an Assistant Professor of Computer Science at the University of Athens. She received her Ph.D. in Computer Science from Stanford University in 2003. Her interests are in the areas of distributed systems and networking. She is a recipient of the NSF CAREER Award (while on the faculty at Harvard), the ERC Starting Grant Award, and the Best Paper Award at ACM SOSP 2003.
PY - 2014/1
Y1 - 2014/1
N2 - In this paper, we propose a modification to the BitTorrent protocol related to its peer unchoking policy. In particular, we apply a novel optimistic unchoking approach that improves the quality of inter-connections amongst peers, i.e., increases the number of directly-connected and interested-in-cooperation peers without penalizing underutilized and/or idle peers. Our optimistic unchoking policy takes into consideration the number of clients currently interested in downloading from a peer that is to be unchoked. Our conjecture is that peers having few clients interested in downloading data from them, should be favored with optimistic unchoke intervals. This enables the peers in question to receive data since they become unchoked faster and in turn, they will trigger the interest of additional clients. In contrast, peers with plenty of "interested" clients should enjoy a lower priority to be selected as planned optimistic unchoked, since these peers likely have enough data to forward; nevertheless, they receive enough data due to tit-for-tat peer reciprocation and are not in need of optimistic unchoking slots. Armed with this realization, we establish an analytical model and prove a significant performance improvement under our modified BitTorrent protocol. Experimental results, also, indicate that our approach significantly outperforms the existing optimistic unchoking policy in three important aspects: first, there is a higher number of interested-in-cooperation and directly-connected peers. Second, since leechers now act as data intermediaries, the load on seeders eases up considerably. Last, a shorter bootstrapping period for fresh peers is achieved. Hence, we claim that our approach helps implement an enhanced BitTorrent protocol and we name it "EnhancedBit".
AB - In this paper, we propose a modification to the BitTorrent protocol related to its peer unchoking policy. In particular, we apply a novel optimistic unchoking approach that improves the quality of inter-connections amongst peers, i.e., increases the number of directly-connected and interested-in-cooperation peers without penalizing underutilized and/or idle peers. Our optimistic unchoking policy takes into consideration the number of clients currently interested in downloading from a peer that is to be unchoked. Our conjecture is that peers having few clients interested in downloading data from them, should be favored with optimistic unchoke intervals. This enables the peers in question to receive data since they become unchoked faster and in turn, they will trigger the interest of additional clients. In contrast, peers with plenty of "interested" clients should enjoy a lower priority to be selected as planned optimistic unchoked, since these peers likely have enough data to forward; nevertheless, they receive enough data due to tit-for-tat peer reciprocation and are not in need of optimistic unchoking slots. Armed with this realization, we establish an analytical model and prove a significant performance improvement under our modified BitTorrent protocol. Experimental results, also, indicate that our approach significantly outperforms the existing optimistic unchoking policy in three important aspects: first, there is a higher number of interested-in-cooperation and directly-connected peers. Second, since leechers now act as data intermediaries, the load on seeders eases up considerably. Last, a shorter bootstrapping period for fresh peers is achieved. Hence, we claim that our approach helps implement an enhanced BitTorrent protocol and we name it "EnhancedBit".
KW - BitTorrent
KW - Content distribution
KW - Incentive protocols
KW - Peer-to-peer (P2P)
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U2 - 10.1016/j.jpdc.2013.08.008
DO - 10.1016/j.jpdc.2013.08.008
M3 - Article
AN - SCOPUS:84890459996
SN - 0743-7315
VL - 74
SP - 1959
EP - 1970
JO - Journal of Parallel and Distributed Computing
JF - Journal of Parallel and Distributed Computing
IS - 1
ER -