forked from quentin/quentin.dufour.io
62 lines
1.7 KiB
Text
62 lines
1.7 KiB
Text
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---
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layout: post
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slug: understanding-bittorrent
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status: draft
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sitemap: false
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title: Understanding BitTorrent
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description: From the network perspective
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categories:
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tags:
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- p2p
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- distributed system
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---
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In this blog post, we will only review the core of BitTorrent.
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We are not interested in its extensions, its optimizations, how it manages spam, etc.
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Compared to the specifications, we will focus our analysis on the importance of parameters and the emerging behaviours that arise when many BitTorrent clients communicate together.
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Moreover, as this (hopefully series of) article will be written in a goal to evaluate Peertube planned implementation of "webstream" (live-streaming over webtorrent), we will use the webtorrent implementation as reference for everything outside specifications.
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We will also try to connect BitTorrent design to some academic papers to put things in perspective.
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## A problem well stated is a problem half solved
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**Discover content**
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**Discover peers**
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**Discover peers' content**
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**Induce a desirable emerging behavior**
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## The .torrent file
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Describes the content of the file to download.
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Multiplexing.
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## The role of the tracker
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Discovering peers.
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What property it must enforce.
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Random sample of the network
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You will have some neighbors.
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## Discovering the chunks known by your neighbors
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introduce some Xerox Taxonomy {% cite DBLP:journals/sigops/DemersGHILSSST88 %}.
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"bitfield" puis "have" -> le push sur l'anti entropy
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If it's done symmetrically, we are in a push+pull model.
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## Downloading the data
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The importance of Local Rarest First {% cite DBLP:conf/infocom/BharambeHP06 %}
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## Conclusion
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BitTorrent is efficient as it multiplexes chunks.
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## References
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{% bibliography --cited %}
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