6,241 research outputs found
Performance of TCP/UDP under Ad Hoc IEEE802.11
TCP is the De facto standard for connection oriented transport layer
protocol, while UDP is the De facto standard for transport layer protocol,
which is used with real time traffic for audio and video. Although there have
been many attempts to measure and analyze the performance of the TCP protocol
in wireless networks, very few research was done on the UDP or the interaction
between TCP and UDP traffic over the wireless link. In this paper, we tudy the
performance of TCP and UDP over IEEE802.11 ad hoc network. We used two
topologies, a string and a mesh topology. Our work indicates that IEEE802.11 as
a ad-hoc network is not very suitable for bulk transfer using TCP. It also
indicates that it is much better for real-time audio. Although one has to be
careful here since real-time audio does require much less bandwidth than the
wireless link bandwidth. Careful and detailed studies are needed to further
clarify that issue.Comment: 9 pages, 5 figures, ICT 2003 (10th International Conference on
Telecommunication
DTMsim - DTM channel simulation in ns
Dynamic Transfer Mode (DTM) is a ring based MAN technology that
provides a channel abstraction with a dynamically adjustable capacity.
TCP is a reliable end to end transport protocol capable of adjusting
its rate. The primary goal of this work is investigate the coupling
of dynamically allocating bandwidth to TCP flows with the affect this
has on the congestion control mechanism of TCP. In particular we
wanted to find scenerios where this scheme does not work, where either
all the link capacity is allocated to TCP or congestion collapse
occurs and no capacity is allocated to TCP. We have created a
simulation environment using ns-2 to investigate TCP over networks
which have a variable capacity link. We begin with a single TCP Tahoe
flow over a fixed bandwidth link and progressively add more complexity
to understand the behaviour of dynamically adjusting link capacity to
TCP and vice versa
MSPlayer: Multi-Source and multi-Path LeverAged YoutubER
Online video streaming through mobile devices has become extremely popular
nowadays. YouTube, for example, reported that the percentage of its traffic
streaming to mobile devices has soared from 6% to more than 40% over the past
two years. Moreover, people are constantly seeking to stream high quality video
for better experience while often suffering from limited bandwidth. Thanks to
the rapid deployment of content delivery networks (CDNs), popular videos are
now replicated at different sites, and users can stream videos from close-by
locations with low latencies. As mobile devices nowadays are equipped with
multiple wireless interfaces (e.g., WiFi and 3G/4G), aggregating bandwidth for
high definition video streaming has become possible.
We propose a client-based video streaming solution, MSPlayer, that takes
advantage of multiple video sources as well as multiple network paths through
different interfaces. MSPlayer reduces start-up latency and provides high
quality video streaming and robust data transport in mobile scenarios. We
experimentally demonstrate our solution on a testbed and through the YouTube
video service.Comment: accepted to ACM CoNEXT'1
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