20 research outputs found
Online multipath convolutional coding for real-time transmission
Most of multipath multimedia streaming proposals use Forward Error Correction
(FEC) approach to protect from packet losses. However, FEC does not sustain
well burst of losses even when packets from a given FEC block are spread over
multiple paths. In this article, we propose an online multipath convolutional
coding for real-time multipath streaming based on an on-the-fly coding scheme
called Tetrys. We evaluate the benefits brought out by this coding scheme
inside an existing FEC multipath load splitting proposal known as Encoded
Multipath Streaming (EMS). We demonstrate that Tetrys consistently outperforms
FEC in both uniform and burst losses with EMS scheme. We also propose a
modification of the standard EMS algorithm that greatly improves the
performance in terms of packet recovery. Finally, we analyze different
spreading policies of the Tetrys redundancy traffic between available paths and
observe that the longer propagation delay path should be preferably used to
carry repair packets.Comment: Online multipath convolutional coding for real-time transmission
(2012
Early Experiences in Traffic Engineering Exploiting Path Diversity: A Practical Approach
Recent literature has proved that stable dynamic routing algorithms have
solid theoretical foundation that makes them suitable to be implemented in a
real protocol, and used in practice in many different operational network
contexts. Such algorithms inherit much of the properties of congestion
controllers implementing one of the possible combination of AQM/ECN schemes at
nodes and flow control at sources. In this paper we propose a linear program
formulation of the multi-commodity flow problem with congestion control, under
max-min fairness, comprising demands with or without exogenous peak rates. Our
evaluations of the gain, using path diversity, in scenarios as intra-domain
traffic engineering and wireless mesh networks encourages real implementations,
especially in presence of hot spots demands and non uniform traffic matrices.
We propose a flow aware perspective of the subject by using a natural
multi-path extension to current congestion controllers and show its performance
with respect to current proposals. Since flow aware architectures exploiting
path diversity are feasible, scalable, robust and nearly optimal in presence of
flows with exogenous peak rates, we claim that our solution rethinked in the
context of realistic traffic assumptions performs as better as an optimal
approach with all the additional benefits of the flow aware paradigm
Programmable overlays via OpenOverlayRouter
Among the different options to instantiate overlays, the Locator/ID Separation Protocol (LISP) [7] has gained significant traction among industry and academia [5], [6], [8]â[11], [14], [15]. Interestingly, LISP offers a standard, inter-domain, and dynamic overlay that enables low capital expenditure (CAPEX) innovation at the network layer [8]. LISP follows a map-and-encap approach where overlay identifiers are mapped to underlay locators. Overlay traffic is encapsulated into locator-based packets and routed through the underlay. LISP leverages a public database to store overlay-to-underlay mappings and on a pull mechanism to retrieve those mappings on demand from the data plane. Therefore, LISP effectively decouples the control and data planes, since control plane policies are pushed to the database rather than to the data plane. Forwarding elements reflect control policies on the data plane by pulling them from the database. In that sense, LISP can be used as an SDN southbound protocol to enable programmable overlay networks [5].Peer ReviewedPostprint (published version
Exploiting the Path Propagation Time Differences in Multipath Transmission with FEC
We consider a transmission of a delay-sensitive data stream from a single
source to a single destination. The reliability of this transmission may suffer
from bursty packet losses - the predominant type of failures in today's
Internet. An effective and well studied solution to this problem is to protect
the data by a Forward Error Correction (FEC) code and send the FEC packets over
multiple paths.
In this paper we show that the performance of such a multipath FEC scheme can
often be further improved. Our key observation is that the propagation times on
the available paths often significantly differ, typically by 10-100ms.
We propose to exploit these differences by appropriate packet scheduling that
we call `Spread'. We evaluate our solution with a precise, analytical
formulation and trace-driven simulations. Our studies show that Spread
substantially outperforms the state-of-the-art solutions. It typically achieves
two- to five-fold improvement (reduction) in the effective loss rate. Or
conversely, keeping the same level of effective loss rate, Spread significantly
decreases the observed delays and helps fighting the delay jitter.Comment: 12 page
Distortion Optimized Multipath Video Streaming
This paper addresses the problem of choosing the best streaming policy for distortion optimal multipath video delivery, under delay constraints. The streaming policy consists in a joint selection of the video packets to be transmitted, as well as their sending time, and the transmission path. A simple streaming model is introduced, which takes into account the video packet importance, and the dependencies among packets, and allows to compute the quality perceived by the receiver, as a function of the streaming policy. We derive an optimization problem based on the video abstraction model, under the assumption that the server knows the state of the network. A detailed analysis of the timing constraints in multipath video streaming provides helpful insights that lead to an efficient algorithm to solve the NP-hard policy optimization problem. We eventually propose a fast heuristic-based algorithm, that still provides close to optimal performance. Thanks to its limited complexity, this novel algorithm is finally implemented in live streaming scenarios, where it only induces a negligible distortion penalty compared to the optimal strategy. Simulation results finally show that the proposed scheduling solutions perform better than common scheduling algorithms, and represent very efficient strategies for both stored and live video streaming scenarios
Exploiting the Path Propagation Time in Multipath Transmission with FEC
We consider a transmission of a delay-sensitive data stream from a single source to a single destination. The reliability of this transmission may suffer from bursty packet losses - the predominant type of failures in today's Internet. An effective and well studied solution to this problem is to protect the data by a Forward Error Correction (FEC) code and send the FEC packets over multiple paths. In this paper we show that the performance of such a multipath FEC scheme can often be further improved. Our key observation is that the propagation times on the available paths often significantly differ, usually by 10-100ms. We propose to exploit these differences by appropriate packet scheduling that we call `Spread'. We evaluate our solution with a precise, analytical formulation and trace-driven simulations. Our studies show that Spread substantially outperforms the state-of-the-art solutions. It typically achieves two- to five-fold improvement (reduction) in the effective loss rate. Or conversely, keeping the same level of effective loss rate, Spread significantly decreases the observed delays and helps fighting the delay jitter