14-02-2013, 10:17 AM
A Network Coding Equivalent Content Distribution Scheme for Efficient
Peer-to-Peer Interactive VoD Streaming
A Network Coding.pdf (Size: 1.26 MB / Downloads: 64)
Abstract
Although random access operations are desirable for on-demand video streaming in peer-to-peer systems, they are difficult
to efficiently achieve due to the asynchronous interactive behaviors of users and the dynamic nature of peers. In this paper, we
propose a network coding equivalent content distribution (NCECD) scheme to efficiently handle interactive video-on-demand (VoD)
operations in peer-to-peer systems. In NCECD, videos are divided into segments that are then further divided into blocks. These
blocks are encoded into independent blocks that are distributed to different peers for local storage. With NCECD, a new client only
needs to connect to a sufficient number of parent peers to be able to view the whole video and rarely needs to find new parents when
performing random access operations. In most existing methods, a new client must search for parent peers containing specific
segments; however, NCECD uses the properties of network coding to cache equivalent content in peers, so that one can pick any
parent without additional searches. Experimental results show that the proposed scheme achieves low startup and jump searching
delays and requires fewer server resources. In addition, we present the analysis of system parameters to achieve reasonable block
loss rates for the proposed scheme.
INTRODUCTION
MULTIMEDIA streaming is now a popular Internet
service. However, efficient streaming to a large client
population is hampered by server bandwidth constraints
and the fact that IP-layer multicast is not universally
supported. Peer-to-peer (P2P) collaborative streaming is a
promising solution to the problem of efficiency. In a P2P
system, each peer requests multimedia content from
specific supplying peers. Then, after receiving the data,
the peer caches it in local storage so that the (receiving) peer
can now become a new supplier for other peers. An
important challenge in a P2P collaborative video-ondemand
(VoD) streaming system is to develop an effective
content distribution scheme that can support a dynamic
network among peers, where autonomic peers can join or
leave the system at any time and any place in the network.
The situation is further complicated by the need to support
random access, such as the trick plays of pause/resume,
jump, fast forward (FF), and rewind.
RELATED WORK
Some P2P systems using linear network coding have already
been developed. Wang and Li [7] presented R2, a new
streaming algorithm designed to combine random network
coding with a randomized push algorithm. R2 focuses on
improving the efficiency of live streaming in terms of startup
buffering delays, resilience to the unpredictable behavior of
peers, and bandwidth saving of streaming servers. Wu et al.
[10] proposed some decentralized strategies to eliminate
conflicts among coexisting streaming overlays on contested
bandwidth and combined those strategies with networkcoding-
based content distribution to realize efficient multioverlay
streaming. Chi et al. [11] proposed a buffer-assisted
search (BAS) scheme to increase partner search performance
by decreasing the size of the index structure. They also
designed a novel scheduling algorithm using the dead-line
aware network coding (DNC) to fully utilize network
resources by adopting an appropriate coding window size.
Linear Network Coding of Segments
To reduce the cost of finding parents, the proposed NCECD
scheme, as illustrated in Fig. 3, utilizes linear network coding
technology [6] for media data distribution. When a sufficient
number of encoded blocks are read fromM different parents,
the original segment can be decoded. The proposed NCECD
scheme is a significant advance over the approach shown in
Fig. 2 because it has a much faster parent search time.
Whereas the basic interleaving scheme requires the child to
find a specific parent with the desired block, the NCECD
scheme does not require the search for specific parents.
Simulation Results
1) Startup and jump delays. Startup delay indicates the first
requested segment location latency. For an accurate comparison
of segment location latency, a child peer must always try
to first connect to the closest parent peer in all schemes. For
the competing schemes and the proposed scheme, a child
peer contacts a number of parent peers and begins downloading
media data in parallel. For the competing schemes, a
child peer only needs to find the first parent peer to start
streaming. While the child peer downloads, it continues to
connect to other parent peers for multisource streaming. In
the proposed scheme, a child peer must contact enough
parent peers to start streaming due to the network coding
limitation. However, since all parent peers can be selected,
the proposed NCECD scheme has a higher probability of
connecting to closer parent peers for downloading, and it
does not need to perform a costly search for parent peers
through a segment distribution topology, as used by other
competing schemes.
CONCLUSION
In this paper, we proposed a novel data distribution scheme
called NCECD to provide interactive VoD services in a P2P
network. In the NCECD scheme, videos are divided into
smaller segments, which are further divided into blocks. The
NCECD scheme applies network coding technology to
generate several encoded blocks by combining the encoding
of all blocks in one segment. These encoded blocks are
distributed to peers on the system.A child peer needs only to
find and link to a sufficient number of parent peers to view
the entire video.