Dejan Kostic

Dejan Kostic

Institute of Radiology, Military Medical Academy, Belgrade, Beograd, Serbia
orcid

Research Focus & Metrics

Academic Career Length

25Years (2002-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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4 March 2015
Verified
Book Chapter
Closed access
PDF file
MKMaciej Kuźniar
Maciej Kuźniar
PPPeter Perešíni
Peter Perešíni
DKDejan Kostic
Dejan Kostic

13 June 2024 in Proceedings of the ACM on Networking
Verified
Journal Article
Open access
CWChangjie Wang
Changjie Wang
MSMariano Scazzariello
Mariano Scazzariello
AFAlireza Farshin
Alireza Farshin
SFSimone Ferlin
Simone Ferlin
DKDejan Kostic
Dejan Kostic
MCMarco Chiesa
Marco Chiesa
This paper explores opportunities to utilize Large Language Models (LLMs) to make network configuration human-friendly, simplifying the configuration of network devices & development of routing algorithms and minimizing errors. We design a set of benchmarks (NetConfEval) to examine the effectiveness of different models in facilitating and automating network configuration. More specifically, we focus on the scenarios where LLMs translate high-level policies, requirements, and descriptions (i.e., specified in natural language) into low-level network configurations & Python code. NetConfEval considers four tasks that could potentially facilitate network configuration, such as (i) generating high-level requirements into a formal specification format, (ii) generating API/function calls from high-level requirements, (iii) developing routing algorithms based on high-level descriptions, and (iv) generating low-level configuration for existing and new protocols based on input documentation. Learning from the results of our study, we propose a set of principles to design LLM-based systems to configure networks. Finally, we present two GPT-4-based prototypes to (i) automatically configure P4-enabled devices from a set of high-level requirements and (ii) integrate LLMs into existing network synthesizers.

13 April 2010
Verified
Conference Paper
Open access
PDF file
NVNedeljko Vasić
Nedeljko Vasić
DKDejan Kostic
Dejan Kostic
Energy consumption,of the Internet is already substantial and it is likely to increase as operators deploy faster equipment,to handle popular bandwidth- intensive services, such as streaming and video-on-demand. Existing work on energy saving considers local adaptation relying primarily on hardware- based techniques, such as sleeping and rate adaptation. We argue that a complete solution requires a network-wide approach that works in conjunc- tion with local measures. However, traditional traffic engineering objectives do not include energy. This paper presents Energy-Aware Traffic engineer- ing (EATe), a technique that takes energy consumption into account while achieving the same traffic rates as the energy-oblivious approaches. EATe uses a scalable, online technique to spread the load among multiple paths so as to increase energy savings. Our extensive ns-2 simulations over re- alistic topologies show that EATe succeeds in moving 21% of the links to the sleep state, while keeping the same sending rates and being close to the optimal energy-aware solution. Further, we demonstrate that EATe suc- cessfully handles changes in traffic load and quickly restores a low overall energy state. Alternatively, EATe can move links to lower energy levels, re- sulting in energy savings of 8%. Finally, EATe can succeed in making 16% of active routers sleep.

10 December 2012
Verified
Conference Paper
Open access
PDF file
MKMaciej Kuzniar
Maciej Kuzniar
PPPeter Peresini
Peter Peresini
MCMarco Canini
Marco Canini
DVDaniele Venzano
Daniele Venzano
DKDejan Kostic
Dejan Kostic
The increasing adoption of Software Defined Networking, and OpenFlow in particular, brings great hope for increasing extensibility and lowering costs of deploying new network functionality. A key component in these networks is the OpenFlow agent, a piece of software that a switch runs to enable remote programmatic access to its forwarding tables. While testing high-level network functionality, the correct behavior and interoperability of any OpenFlow agent are taken for granted. However, existing tools for testing agents are not exhaustive nor systematic, and only check that the agent’s basic functionality works. In addition, the rapidly changing and sometimes vague OpenFlow specifications can result in multiple implementations that behave differently. This paper presents SOFT, an approach for testing the interoperability of OpenFlow switches. Our key insight is in automatically identifying the testing inputs that cause different OpenFlow agent implementations to behave inconsistently. To this end, we first symbolically execute each agent under test in isolation to derive which set of inputs causes which behavior. We then crosscheck all distinct behaviors across different agent implementations and evaluate whether a common input subset causes inconsistent behaviors. Our evaluation shows that our tool identified several inconsistencies between the publicly available Reference OpenFlow switch and Open vSwitch implementations.QC 20140704

3 March 2012
Verified
Conference Paper
Open access
NVNedeljko Vasić
Nedeljko Vasić
DNDejan Novaković
Dejan Novaković
SMSvetozar Miučin
Svetozar Miučin
DKDejan Kostic
Dejan Kostic
RBRicardo Bianchini
Ricardo Bianchini
Effective resource management of virtualized environments is a challenging task. State-of-the-art management systems either rely on analytical models or evaluate resource allocations by running actual experiments. However, both approaches incur a significant overhead once the workload changes. The former needs to recalibrate and re-validate models, whereas the latter has to run a new set of experiments to select a new resource allocation. During the adaptation period, the system may run with an inefficient configuration.Qc 20140707

25 March 2019
Verified
Conference Paper
Open access
PDF file
AFAlireza Farshin
Alireza Farshin
ARAmir Roozbeh
Amir Roozbeh
GMGerald Q. Maguire
Gerald Q. Maguire
DKDejan Kostic
Dejan Kostic