NavTalks
From Navigators
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<td style="width:10%">4 October</td> | <td style="width:10%">4 October</td> | ||
- | <td style="width:30%"> Marcus Völp (Research Scientist, CritiX, SnT, Univ. of Luxembourg) </td> | + | <td style="width:30%">Marcus Völp (Research Scientist, CritiX, SnT, Univ. of Luxembourg) </td> |
<td style="width:50%"><span title="As you are well aware, many practical concerns in systems aiming at Byzantine fault and intrusion tolerance require reaching consensus in difficult situations. For example, to remain exhaustion safe, replacing permanently damaged replicas requires relocating the replicated functionality to a fresh set of spares, necessitating conensus on the new group of active replicas. While group membership protocols exists for this task, we are also aware of their limitations (faults in the adaptation infrastructure (recurring the problem in the servers implementing it), operation modes that cannot reach consensus (aka Cheap / ReBFT minimal mode), etc.) that make it extremely difficult (if not impossible) to perform these reconfigurations in a reliable manner. In this talk, I would like to give you an overview over some of the current (unsolved) research problems we work on in CritiX and which I would like to discuss with you while here. I would like to share my view on our hinge that in some of the above settings, there is still hidden an impossibility result, possibly rendering CheapBFT (or at least generalizations of it to arbitrary quorums) incorrect, but motivating a novel design principle, which we call reflective consensus: Rather than solving the difficult, but naturally arising consensus problem (e.g., consensus on group membership in case of exhaustion failure due to an increasing threat level), we reflect consensus to the same set of replicas where it will occur, but in a simpler version that is possibly even executed at a different time (e.g., proactively when the system is not yet exhaustion failed). ">Reflective Consensus</span></td> | <td style="width:50%"><span title="As you are well aware, many practical concerns in systems aiming at Byzantine fault and intrusion tolerance require reaching consensus in difficult situations. For example, to remain exhaustion safe, replacing permanently damaged replicas requires relocating the replicated functionality to a fresh set of spares, necessitating conensus on the new group of active replicas. While group membership protocols exists for this task, we are also aware of their limitations (faults in the adaptation infrastructure (recurring the problem in the servers implementing it), operation modes that cannot reach consensus (aka Cheap / ReBFT minimal mode), etc.) that make it extremely difficult (if not impossible) to perform these reconfigurations in a reliable manner. In this talk, I would like to give you an overview over some of the current (unsolved) research problems we work on in CritiX and which I would like to discuss with you while here. I would like to share my view on our hinge that in some of the above settings, there is still hidden an impossibility result, possibly rendering CheapBFT (or at least generalizations of it to arbitrary quorums) incorrect, but motivating a novel design principle, which we call reflective consensus: Rather than solving the difficult, but naturally arising consensus problem (e.g., consensus on group membership in case of exhaustion failure due to an increasing threat level), we reflect consensus to the same set of replicas where it will occur, but in a simpler version that is possibly even executed at a different time (e.g., proactively when the system is not yet exhaustion failed). ">Reflective Consensus</span></td> | ||
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<td style="width:10%">18 October</td> | <td style="width:10%">18 October</td> | ||
- | <td style="width:30%"> Yair Amir (Professor, Johns Hopkins University) </td> | + | <td style="width:30%">Yair Amir (Professor, Johns Hopkins University) </td> |
- | <td style="width:50%"> Timely, Reliable, and Cost-Effective Internet Transport Service using Structured Overlay Networks</td> | + | <td style="width:50%"><span title="Emerging applications such as remote manipulation, collaborative virtual reality, or remote robotic surgery require communication that is both timely and reliable, but the Internet natively supports only communication that is either completely reliable with no timeliness guarantees (e.g. TCP) or timely with only best-effort reliability (e.g. UDP). We present an overlay transport service that can provide highly reliable communication while meeting stringent timeliness guarantees (e.g. 130ms round-trip latency across the US) over the Internet. |
+ | |||
+ | To enable routing schemes that can support the necessary timeliness and reliability, we introduce dissemination graphs, providing a unified framework for specifying routing schemes ranging from a single path, to multiple disjoint paths, to arbitrary graphs. Based on an extensive analysis of real-world network data, we develop a timely dissemination-graph-based routing method that can add targeted redundancy in problematic areas of the network. We show that this approach can cover close to 99% of the performance gap between a traditional single-path approach and an optimal (but prohibitively expensive) scheme.">Timely, Reliable, and Cost-Effective Internet Transport Service using Structured Overlay Networks</span></td> | ||
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Revision as of 11:38, 12 November 2018
The Navtalks is a series of informal talks given by Navigators members or some special guests about every two-weeks at Ciências, ULisboa.
Leave mouse over title's presentation to read the abstract.
Contents |
September 2018
20 September | Alysson Bessani | SMaRtChain: A Principled Design for a New Generation of Blockchains | |
20 September | Rui Miguel | Named Data Networking with Programmable Switches |
October 2018
4 October | Bruno Vavala (Research Scientist in Intel Labs) | Private Data Objects | |
4 October | Marcus Völp (Research Scientist, CritiX, SnT, Univ. of Luxembourg) | Reflective Consensus | |
18 October | Yair Amir (Professor, Johns Hopkins University) | Timely, Reliable, and Cost-Effective Internet Transport Service using Structured Overlay Networks |
November 2018
13/11 | Salvatore Signorello | The Past, the Present and some Future of Interest Flooding Attacks in Named-Data Networking | |
13/11 | Tiago Oliveira | Vawlt - Privacy-Centered Cloud Storage | |
27/11 | Nuno Neves | ||
27/11 | Ricardo Mendes |
December 2018
11/12 | António Casimiro | |||
11/12 | Carlos Nascimento |
January 2019
15/01 | Fernando Alves | ||
15/01 | Ibéria Medeiros | ||
29/01 | Fernando Ramos | ||
29/01 | Miguel Garcia |
February 2019
19/02 | Ana Fidalgo | ||
19/02 | João Sousa |
March 2019
12/03 | Pedro Gaspar | ||
12/03 | Ricardo Morgado | ||
26/03 | André Oliveira | ||
26/03 | Nuno Dionísio |
April 2019
09/04 | Adriano Serckumecka | ||
09/04 | Tulio Ribeiro | ||
30/04 | Miguel Moreira | ||
30/04 | Pedro Ferreira |
May 2019
14/05 | Diogo Gonçalves | ||
14/05 | Vinicius Cogo | ||
28/05 | Francisco Araújo | ||
28/05 | Miguel Matos |
June 2019
11/06 | Eric Vial | ||
11/06 | Robin Vassantlal | ||
25/06 | João Pinto | ||
25/06 | Tiago Correia |