22,585 research outputs found
ABC: A Simple Explicit Congestion Controller for Wireless Networks
We propose Accel-Brake Control (ABC), a simple and deployable explicit
congestion control protocol for network paths with time-varying wireless links.
ABC routers mark each packet with an "accelerate" or "brake", which causes
senders to slightly increase or decrease their congestion windows. Routers use
this feedback to quickly guide senders towards a desired target rate. ABC
requires no changes to header formats or user devices, but achieves better
performance than XCP. ABC is also incrementally deployable; it operates
correctly when the bottleneck is a non-ABC router, and can coexist with non-ABC
traffic sharing the same bottleneck link. We evaluate ABC using a Wi-Fi
implementation and trace-driven emulation of cellular links. ABC achieves
30-40% higher throughput than Cubic+Codel for similar delays, and 2.2X lower
delays than BBR on a Wi-Fi path. On cellular network paths, ABC achieves 50%
higher throughput than Cubic+Codel
Modeling Stochastic Lead Times in Multi-Echelon Systems
In many multi-echelon inventory systems, the lead times are random variables. A common and reasonable assumption in most models is that replenishment orders do not cross, which implies that successive lead times are correlated. However, the process that generates such lead times is usually not well defined, which is especially a problem for simulation modeling. In this paper, we use results from queuing theory to define a set of simple lead time processes guaranteeing that (a) orders do not cross and (b) prespecified means and variances of all lead times in the multiechelon system are attained
Collaborative Uploading in Heterogeneous Networks: Optimal and Adaptive Strategies
Collaborative uploading describes a type of crowdsourcing scenario in
networked environments where a device utilizes multiple paths over neighboring
devices to upload content to a centralized processing entity such as a cloud
service. Intermediate devices may aggregate and preprocess this data stream.
Such scenarios arise in the composition and aggregation of information, e.g.,
from smartphones or sensors. We use a queuing theoretic description of the
collaborative uploading scenario, capturing the ability to split data into
chunks that are then transmitted over multiple paths, and finally merged at the
destination. We analyze replication and allocation strategies that control the
mapping of data to paths and provide closed-form expressions that pinpoint the
optimal strategy given a description of the paths' service distributions.
Finally, we provide an online path-aware adaptation of the allocation strategy
that uses statistical inference to sequentially minimize the expected waiting
time for the uploaded data. Numerical results show the effectiveness of the
adaptive approach compared to the proportional allocation and a variant of the
join-the-shortest-queue allocation, especially for bursty path conditions.Comment: 15 pages, 11 figures, extended version of a conference paper accepted
for publication in the Proceedings of the IEEE International Conference on
Computer Communications (INFOCOM), 201
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