Christoph Gärtner

dblp:267/2834 · DBLP profile ↗
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8ranked-venue papers
4as first author
6since 2021 · last 2024
0000-0003-2083-9869ORCID · corroborated

Domains — the database's venue-derived domains; a paper can count in several

Computer networks · 4 · 3 first-author · 4 since 2021Artificial intelligence and machine learning · 1
YearPublicationVenuePosition
2024 RDA: Residence Delay Aggregation for Time-Sensitive Networking
abstract
Time-Sensitive Networking (TSN) enables deterministic and low-latency communication for real-time applications over Ethernet. That is accomplished by leveraging scheduling and shaping techniques configured for each egress port within the network switches. Although Time Aware Shaper (TAS) is a promising solution for TSN, its adoption often involves substantial complexity. In this work, we propose Residence Delay Aggregation (RDA), a novel asynchronous TSN mechanism that offers dynamic traffic scheduling adapted to the traffic load. Specifically, the proposed RDA mechanism provides upper bound delays similar to other asynchronous TSN mechanisms while improving the flexibility of traffic scheduling and reducing the deployment complexity.
Chengbo Zhou, Christoph Gärtner, Amr Rizk, Boris Koldehofe, Björn Scheuermann 0001, Ralf Kundel
NOMS2
2023 Demo: Flexibility-aware Network Management of Time-Sensitive Flows
abstract
We investigate the application of a recently published metric for flexibility in the context of combined port queue schedules of network paths in Time-Sensitive Networks (TSN). TSN comprises a set of specifications for deterministic networking, including support for scheduled traffic with guaranteed deterministic end-to-end delays. Typically, scheduler resource allocation in TSN disregards flexibility of scheduler configurations. Essentially, the notion of flexibility of paths comprising multiple concatenated ports having each a TSN configuration is based on the number of possible embeddings, i.e., resource allocations, for a new flow of a given specification (size and delay deadline) along that path. This demonstration allows the user to define TSN schedules along network paths and, hence, illustrates the behavior and benefit of performing flexibility-aware TSN configuration.
Christoph Gärtner, Amr Rizk, Boris Koldehofe, René Guillaume, Ralf Kundel, Ralf Steinmetz
SIGCOMM1
2023 Fast incremental reconfiguration of dynamic time-sensitive networks at runtime
Christoph Gärtner, Amr Rizk, Boris Koldehofe, René Guillaume, Ralf Kundel, Ralf Steinmetz
Comput. Networks1
2021 Poster: Reverse-Path Congestion Notification: Accelerating the Congestion Control Feedback Loop
abstract
Congestion control mechanisms in computer networks rely mainly on a feedback loop having a reaction time equal to the flow RTT. Reducing this feedback time helps the sender to react faster to changing network conditions such as congestion. In this work, we propose reverse-path congestion notification on top of programmable networking switches. Our approach can significantly lower the reaction time, such that the congestion control implementation can adapt much faster to changing network conditions. The proposed approach aims to work with current TCP implementations with no required changes to the communication endpoints. Last, we show how the presented approach could be realized by utilizing off-the-shelf programmable switches.
Ralf Kundel, Nehal Baganal Krishna, Christoph Gärtner, Tobias Meuser, Amr Rizk
ICNP3
2021 POSTER: Leveraging PIFO Queues for Scheduling in Time-Sensitive Networks
abstract
Time-Sensitive Networking emerged as a convergent Ethernet-based real-time networking standard for industrial applications. To support real-time, jitter-free isochronous traffic the corresponding TSN mechanism denoted Time Aware Shaper requires special hardware support. In this work, we propose a path to building TSN networks on top of programmable switches. Specifically, we show here how to leverage a data structure amenable to programmable data planes known as Push-in First-out (PIFO) queue to support TSN traffic scheduling for isochronous real-time, as well as, best effort traffic.
Christoph Gärtner, Amr Rizk, Boris Koldehofe, Rhaban Hark, René Guillaume, Ralf Kundel, Ralf Steinmetz
LANMAN1
2021 Leveraging Flexibility of Time-Sensitive Networks for dynamic Reconfigurability
abstract
In Time-Sensitive Networks (TSN) applications with the highest real-time flow requirements are deployed using the Time-Aware Shaper which requires careful planning and scheduling of flows before deployment. Such deployments lack support for dynamic industrial scenarios such as modular machine assembly and reconfiguration, which require a flexible transition between real-time tasks. In contrast, state-of-the-art techniques rely on flow rescheduling and deployment in conjunction with undesired network downtime. Existing works on adapting schedules to traffic admissions are limited in their ability to choose suitable flows to account for future tasks. In this paper, we aim to leverage the flexibility of scheduler configurations to enable TSN dynamic reconfigurability at runtime. We propose a notion of flexibility for TSN Time-Aware Shaper schedules which we utilize to decide the admissibility of consecutive real-time tasks.
Christoph Gärtner, Amr Rizk, Boris Koldehofe, Rhaban Hark, René Guillaume, Ralf Steinmetz
Networking1
2020 Online Meta-Forest for Regression Data Streams
abstract
Stream learning is essential when there is limited memory, time and computational power. However, existing streaming methods are mostly designed for classification with only a few exceptions for regression problems. Although being fast, the performance of these online regression methods is inadequate due to their dependence on merely linear models. Besides, only a few stream methods are based on meta-learning that aims at facilitating the dynamic choice of the right model. Nevertheless, these approaches are restricted to recommend learners on a window and not on the instance level. In this paper, we present a novel approach, named Online Meta-Forest, that incrementally induces an ensemble of meta-learners that selects the best set of predictors for each test example. Each meta-learner has the ability to find a non-linear mapping of the input space to the set of induced models. We conduct a series of experiments demonstrating that Online Meta-Forest outperforms related methods on 16 out of 25 evaluated benchmark and domain datasets in transportation.
Ammar Shaker, Christoph Gärtner, Shujian Yu
IJCNN2
2020 Flexible Content-based Publish/Subscribe over Programmable Data Planes
abstract
Publish/subscribe systems have to react fast on changes in their environment while handling many events with low end-to-end latency and high throughput. Moving the broker functionality of publish/subscribe systems to the underlying network layer reduces the path length of events and, in addition, forwarding benefits from powerful and programmable hardware. So far attempts of underlay publish/subscribe depend on a specific API of the network devices, e. g., the OpenFlow protocol, which have restrictions in dealing with dynamic devices and corresponding changes in the introduced attribute names for matching and filtering events.In this work, we focus on the next generation of network devices, which are envisioned to provide reconfigurable hardware components, specified by the open P4 description language. We introduce two new approaches that enable a flexible and generic attribute/value encoding, understandable by P4-capable packet processors, to benefit from the performance properties of hardware. Furthermore, the proposed approaches reduce the effort in encoding and decoding event messages.
Ralf Kundel, Christoph Gärtner, Manisha Luthra, Sukanya Bhowmik, Boris Koldehofe
NOMS2