SoC Projects : Peer To Peer Streaming
There was one project application in this area that is summarised
here. This page contains the depersonalised content, which can be
consolidated as necessary. The depersonalisation is for privacy
reasons, credit is here due to those who spent the time writing these
Peer-to-Peer streaming architecture using Kamaelia
In recent years the concept of peer-to-peer streaming has received increased attention from the academic and
research communities, partly because the Internet doesn't widely support multicast, and because of the need for
a large scale content distribution system.
The project I would like to work on is an experiment with such an architecture. The core idea is that each peer
that takes part in such an architecture can receive data segments from several other peers, aggregate and play them,
and also server data segments (at various rates), to other peers. The Kamaelia-based approach is to have a component
that receives media streaming segments from a number of similar components, and can also serve a number of other components with the media it receives. It should be able to take advantage of local multicast facilities.
From the perspective of the challenges that BBC Research is facing, this project would be an attempt to integrate
P2P and Multicast, because it provide a way to deliver media streaming information between smaller multicast islands,
where effective communication will be achieved by more efficient, lower-level, mechanisms.
Here is a selected list of papers regarding these topics:
The core component to the architecture is a component that can receive data segments from N other components, aggregate them, and send them to a "player" component. Also, based on the underlying allocation algorithm, it can serve data segments to other peers itself. For the beginning the streaming data will be a simple integer stream, and the "player" a checker for consistency (mainly, whether the segments are in the right order, and whether there are missing segments).
A subset of peers will have only one input, from a component named a "seeder", which will generate the data. The discovery and the process of building the architecture still present some challenges, and I will probably start with a statically specified architecture; using a "building" utility, that reads this topology's description from a file and builds its logical structure in Python by interconnecting the "peer" components. Also, I will try to explore different algorithms and strategies for initial building of the topology, and its maintenance.
A special case is that of the multicast islands. Because they support more efficient ways of communication, it is reasonable that they are treated as a single peer by the external network. This possibility suggests the following architecture choice: each peer can be linked to its own Multicast_transceiver, that communicates to the multicast island this peer takes part in. This separation allows us to receive data "into" the multicast island through more than one peers, a more realistic approach to a high demand network.
To sum up we have:
* seeders, that generate the data
* peers, that have a sense of the topology surrounding them; they receive streaming data from several other peers and feed it into the player; moreover, it can be connected to a Multicast_transceiver in case it takes part in a multicast island, and can relay streaming data to a number of other peers
* player, which will aggregate the data segments in the correct order, perform buffering, if required, and "play" the data, depending on its type
Problems that need to be addressed:
* initial topology setup
* topology maintenance
* multicast islands identification
* from a peer's point of view, the network discovery
Finally, I would like to try some experiments using "real" audio or video streaming, as opposed to simplified mock-up data.
* 20 June - detailed specifications for the architecture and the peer component
* 30 June - implementation of the peer, seeder and player components, for a simplified data stream
* 20 July - multicast and support for audio or video data
* 1 August - automatic topology discovering, using one or more directories
* 20 August - documentation, testing, experimenting
* the implementation of the "peer", "seeder" and "player" components, with documentation
* the utilities used to set up a topology
* a detailed report describing the approach and algorithms used
* a tutorial for using the components