3 research outputs found
LEGOStore: A Linearizable Geo-Distributed Store Combining Replication and Erasure Coding
We design and implement LEGOStore, an erasure coding (EC) based linearizable
data store over geo-distributed public cloud data centers (DCs). For such a
data store, the confluence of the following factors opens up opportunities for
EC to be latency-competitive with replication: (a) the necessity of
communicating with remote DCs to tolerate entire DC failures and implement
linearizability; and (b) the emergence of DCs near most large population
centers. LEGOStore employs an optimization framework that, for a given object,
carefully chooses among replication and EC, as well as among various DC
placements to minimize overall costs. To handle workload dynamism, LEGOStore
employs a novel agile reconfiguration protocol. Our evaluation using a
LEGOStore prototype spanning 9 Google Cloud Platform DCs demonstrates the
efficacy of our ideas. We observe cost savings ranging from moderate (5-20\%)
to significant (60\%) over baselines representing the state of the art while
meeting tail latency SLOs. Our reconfiguration protocol is able to transition
key placements in 3 to 4 inter-DC RTTs ( 1s in our experiments), allowing
for agile adaptation to dynamic conditions
On the Exploration of FPGAs and High-Level Synthesis Capabilities on Multi-Gigabit-per-Second Networks
Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Escuela Politécnica Superior, Departamento de Tecnología Electrónica y de las Comunicaciones. Fecha de lectura: 24-01-2020Traffic on computer networks has faced an exponential grown in recent years.
Both links and communication equipment had to adapt in order to provide
a minimum quality of service required for current needs. However, in recent
years, a few factors have prevented commercial off-the-shelf hardware from
being able to keep pace with this growth rate, consequently, some software tools are
struggling to fulfill their tasks, especially at speeds higher than 10 Gbit/s. For this reason,
Field Programmable Gate Arrays (FPGAs) have arisen as an alternative to address the
most demanding tasks without the need to design an application specific integrated
circuit, this is in part to their flexibility and programmability in the field. Needless to say,
developing for FPGAs is well-known to be complex. Therefore, in this thesis we tackle
the use of FPGAs and High-Level Synthesis (HLS) languages in the context of computer
networks. We focus on the use of FPGA both in computer network monitoring application
and reliable data transmission at very high-speed. On the other hand, we intend to shed
light on the use of high level synthesis languages and boost FPGA applicability in the
context of computer networks so as to reduce development time and design complexity.
In the first part of the thesis, devoted to computer network monitoring. We take advantage
of the FPGA determinism in order to implement active monitoring probes, which
consist on sending a train of packets which is later used to obtain network parameters.
In this case, the determinism is key to reduce the uncertainty of the measurements.
The results of our experiments show that the FPGA implementations are much more
accurate and more precise than the software counterpart. At the same time, the FPGA
implementation is scalable in terms of network speed — 1, 10 and 100 Gbit/s. In the context of passive monitoring, we leverage the FPGA architecture to implement algorithms
able to thin cyphered traffic as well as removing duplicate packets. These two algorithms
straightforward in principle, but very useful to help traditional network analysis tools to
cope with their task at higher network speeds. On one hand, processing cyphered traffic
bring little benefits, on the other hand, processing duplicate traffic impacts negatively in
the performance of the software tools.
In the second part of the thesis, devoted to the TCP/IP stack. We explore the current
limitations of reliable data transmission using standard software at very high-speed.
Nowadays, the network is becoming an important bottleneck to fulfill current needs, in
particular in data centers. What is more, in recent years the deployment of 100 Gbit/s
network links has started. Consequently, there has been an increase scrutiny of how
networking functionality is deployed, furthermore, a wide range of approaches are
currently being explored to increase the efficiency of networks and tailor its functionality
to the actual needs of the application at hand. FPGAs arise as the perfect alternative to
deal with this problem. For this reason, in this thesis we develop Limago an FPGA-based
open-source implementation of a TCP/IP stack operating at 100 Gbit/s for Xilinx’s FPGAs.
Limago not only provides an unprecedented throughput, but also, provides a tiny latency
when compared to the software implementations, at least fifteen times. Limago is a key
contribution in some of the hottest topic at the moment, for instance, network-attached
FPGA and in-network data processing