A Study on Network Media-aware Scheduling for Robust P2P Streaming
Yong-Hyuk Moon
t
, Jae-Hoon Nah
t
,
and Chan-Hyun Youn
tt
tElectronics
and
Telecommunications Research Institute (ETRI), Daejeon, South Korea
tt
LANSA, Information
and
Communications University (ICU), Daejeon, South Korea
{yhmoon, j hnah}@etri.re.kr; {chyoun}@icu.ac.kr
Abstract-
Currently, network media (i.e., video) tends to
be delivered to users through IP-based networks,
particularly P2P. However, due to operational
complexities of risky P2P-based streaming model and less
reflecting about media characteristics, the optimized
performance (e.g., QoS
or
QoE)
is
rarely expected.
Therefore,
we
describe constraints and then discuss our
solutions of P2P video streaming services with respects to
structure, operation, network, and media.
Keywords
- Network Media-aware Scheduling,
Streaming scheduling, P2P IPTV
1.
Introduction
Recently, P2P has shown great possibilities with
respect to scalable collaboration and interaction among
distributed resources, in various research and industrial
areas such
as
virtual office, VoIP, file sharing, video
streaming, and so
on.
In particular, video
is
the key
source
of
multimedia services and streaming technique
of
using P2P manner
is
widely used for real-time or
on-demand Internet TV service, for example P2P IPTV
[1
].
Generally, a video data consists
of
many encoded-
frames, depending on codec specifications such
as
MPEG4 [2], H.264 [3], and SVC (H.264/AVC)
[4].
A
frame
is
segmented into one or more packets for
transmission whose size
is
less than MTU (Maximum
Transmission Unit) because
of
avoiding fragmentation.
Then this packetized media
is
transmitted
to
heterogeneous rendering devices with different
requirements. However, a video quality easily varies
with network conditions and media characteristics;
in
other words, media packets are characterized with
dynamic variations in bandwidth, loss rate, delay, and
jitter and these network conditions can be
unpredictably changeable in any instant
of
time during
video transmission. As a good example
of
that in
perspective
of
P2P networks, random peer departures
(called chum)
[6]
or network congestion
is
a primary
reason to cause the unreliable video streaming.
For solving these constraints, a receiver for
instance, a playback device or movie viewer,
try to
request a retransmission
of
lost or discarded packet
during video streaming. This retransmission process
can be achievable by feedback mechanism
as
probing
technique which
is
necessary for rapid adaptation
of
network conditions; thus, a model
of
estimating the
probability
of
a video packet loss and discarding
is
significantly required
in
overlay streaming
environments. Nevertheless, many previous studies [7,
8,
9,
and
10]
on scheduling
of
media streaming
in
P2P
networks tend to mainly focus on networking issues
which are strongly depend on a particular P2P
architecture such
as
a tree-based model and mesh-pull
model. Therefore, it
is
considerably necessary to reflect
on media characteristics such
as
inter-frame
dependency, motion prediction, and others. Therefore,
in
this paper,
we
will present our study on packet-level
scheduling algorithm with awareness
of
network
conditions and media characteristics simultaneously by
using a feedback strategy and deadline expectation
scheme, respectively for guaranteeing high quality
of
P2P streaming. Furthermore,
in
a full paper,
we
will
show comparative and contrastive features
of
each
detailed specification
of
previously proposed
scheduling algorithms and propose several important
findings which can be helpful to improve a
performance
of
video streaming scheduling
in
P2P-
based network.
2.
Related Works
Mostly, a degradation
of
video quality during
transmission
is
caused by an unexpected packet loss
and discarding due to unstable network status and late
arrival, respectively. This problem can be definitely
condensed
as
follows [11,
12].
ISBN 978-89-5519-139-4
-1852-
Feb. 15-18,2009 ICACT 2009