Content Delivery
Infrastructures for Live Streaming Progress Report
held
at the TF-VVC Face 2 Face meeting of June 9 2005, Poznam
Outline
OpenCDN
is an application-level
Content
Delivery Network for
replication and splitting of live multimedia content
and distributed caching of VoD, by deployment of a
Streaming Relay Overlay
Network. It has grown as an
OpenSource project, and can be adapted to any kind of streaming
technology. Free participation can be in the form of development and
testing, set up of remote replication nodes, and contribution of live
feeds.
Goals
When
and if the OpenCDN project will be widely endorsed, netcasting to large
audiences will become as easy as meeting friends at pub. No ubiquitous
multicast routing will be necessary, and TV will become
obsolete.
Artistic
and cultural events will reach broader audiences, students
will attend to courses from home, videoconferences will become
Internet
talk-shows.
Achievements
Started
in 2004, development still proceed unfounded (but I'm a bad
manager). Despite this, two streaming technologies are actually
supported, Apple
Darwin Streaming Server, and Real
Helix Universal
Server, which can be hosted on the same machine. Contributing
sources announce Metadata about their contents, and these are
published at
a Portal, where viewers can ask for an appropriate surrogate
server. Request Routing,
Distribution, and Delivery,
is
performed in the background by an XML-RPC based distributed
architecture, which benefits of an inter-entity authentication
infrastructure, and of a UDP
probing mechanism, which also provides resilience against nodes and
network outages.
Forthcoming features
Actual
determination of a topologically efficient surrogate for a given
viewer,
is based on manually configured routing information. It will be
substituted by an RTT estimate
in between the candidate Last Hop
Relays,
and the viewer location
A web-based configuration
interface
will be
developed in order to ease administration tasks
Better documentation
will be provided, as well as How-To guides, about replication node and
content source provision
Embedding of the requested
content
playback within the request page at the portal will be analyzed and
developed
Aging of stale information
will
be performed, both at the centralized control entity, and at the
distributed nodes
A policy agreement to
be subscribed by contributors will be drawn, together with a community
registration and communication paradigm
A graphical representation of
the resulting topology will
be provided, together with an easy access
to statistical information about nodes usage
Participation
Installation
and configuration of a replication node requires no more than a few
hours work, and costs really nothing, as a cheap LinuxBox will
suffice. Contents contribution just requires an ADSL connection,
and only needs a publicly available multimedia encoder (such as
VideoLAN, MPEG4IP, Real Producer). Development is made in Perl, and a
rich ToDo list is present in the distribution. Code can be downloaded
from
SourceForge,
where some mailing lists can be found also.
Alessandro
Falaschi - June
8, 2005