19 research outputs found
A 3-player protocol preventing persistence in strategic contention with limited feedback
In this paper, we study contention resolution protocols from a game-theoretic
perspective. In a recent work, we considered acknowledgment-based protocols,
where a user gets feedback from the channel only when she attempts
transmission. In this case she will learn whether her transmission was
successful or not. One of the main results of ESA2016 was that no
acknowledgment-based protocol can be in equilibrium. In fact, it seems that
many natural acknowledgment-based protocols fail to prevent users from
unilaterally switching to persistent protocols that always transmit with
probability 1. It is therefore natural to ask how powerful a protocol must be
so that it can beat persistent deviators.
In this paper we consider age-based protocols, which can be described by a
sequence of probabilities of transmitting in each time step. Those
probabilities are given beforehand and do not change based on the transmission
history. We present a 3-player age-based protocol that can prevent users from
unilaterally deviating to a persistent protocol in order to decrease their
expected transmission time. It is worth noting that the answer to this question
does not follow from the results and proof ideas of ESA2016. Our protocol is
non-trivial, in the sense that, when all players use it, finite expected
transmission time is guaranteed. In fact, we show that this protocol is
preferable to any deadline protocol in which, after some fixed time, attempt
transmission with probability 1 in every subsequent step. An advantage of our
protocol is that it is very simple to describe, and users only need a counter
to keep track of time. Whether there exist -player age-based protocols that
do not use counters and can prevent persistence is left as an open problem for
future research.Comment: arXiv admin note: substantial text overlap with arXiv:1606.0658
Modeling and dimensioning hierarchical storage systems for low-delay video services
In order to cost-effectively accommodate a large number of titles in a video system, a hierarchical storage system can be used. In this system, not-so-popular video files are stored in a tertiary level such as a disk/tape library. These files are transferred, or "staged," to a secondary level composed of magnetic disks before being streamed to the users. This system overcomes the current limitations in using disk/tape libraries to stream videos and resolves the bandwidth difference between staging and streaming. In this paper, we present, via analysis, a model of the system and determine the minimum storage and bandwidth required, at each level, to meet a given user delay goal. We also analyze a number of system operations pertaining to whether or not a file is played while it is being staged (i.e., stage-streaming) and whether or not the displayed segments are deleted (i.e., trail-deletion). We show that stage-streaming and trail-deletion can achieve substantially lower bandwidth and storage requirements. In order to further increase the streaming and storage scalability, a distributed storage system can be used where multiple local servers are put close to user pools and get their files from one of the libraries through a network. We extend the models developed to such a system and specify the resource requirements to meet a given delay goal
Performance and Cost Comparison of Mirroring- and Parity-Based Reliability Schemes for Video Servers
Der 'kleine Parteitag' in Moskau (28. Juni - 1. Juli 1988)
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