Gábor Lencse

6508061114

Publications - 46

Performance Analysis of MPT-GRE Multipath Networks Under Out-of-Order Packet Arrival

Naseer Al-Imareen Gábor Lencse

Publication Name: Electronics Switzerland

Publication Date: 2025-06-01

Volume: 14

Issue: 11

Page Range: Unknown

Description:

Network packets may arrive out of their original order due to network delays, transmission speed variations, congestion, or uneven resource distribution. These factors cause significant challenges to network performance. These challenges result in jitter, packet loss, and reduced throughput, negatively affecting the efficient arrangement of packets. The Multipath tunnel-Generic Routing Encapsulation (MPT-GRE) architecture addresses this issue through a packet reordering mechanism designed for multipath GRE with User Datagram Protocol (UDP) encapsulation networks. This study investigates and analyses the path-specific delays, jitter, and transmission speed constraints to evaluate the influence of out-of-order packets on the MPT-GRE tunnel throughput aggregation capability. By comparing scenarios with and without the re-ordering mechanism, the results demonstrate that the reordering mechanism substantially improves the traffic throughput in symmetric and asymmetric channel configurations. Additionally, the study emphasizes the critical role of optimizing the reordering window parameter for effective performance. These findings confirm that packet reordering mechanisms significantly enhance MPT-GRE network performance by reducing the negative effects of delays and out-of-order arrivals.

Open Access: Yes

DOI: 10.3390/electronics14112138

Enhancing Real-Time Video Streaming Quality via MPT-GRE Multipath Network

Naseer Al-Imareen Gábor Lencse

Publication Name: Electronics Switzerland

Publication Date: 2025-02-01

Volume: 14

Issue: 3

Page Range: Unknown

Description:

The demand for real-time 4K video streaming has introduced technical challenges due to the high bandwidth, low latency, and minimal jitter required for high-quality user experience. Traditional single-path networks often fail to meet these requirements, especially under network congestion and packet loss conditions, which degrade video quality and disrupt streaming stability. This study evaluates Multipath tunnel- Generic Routing Encapsulation (MPT-GRE), a technology designed to address these challenges by enabling simultaneous data transmission across multiple network paths. By aggregating bandwidth and adapting dynamically to network conditions, MPT-GRE enhances resilience, maintains quality during network disruptions, and offers throughput nearly equal to the sum of its physical paths’ throughput. This feature ensures that even if one path fails, the technology seamlessly continues streaming through the remaining path, significantly reducing interruptions. We measured key video quality metrics to assess MPT-GRE’s performance: Structural Similarity Index Measure (SSIM), Mean Squared Error (MSE), and Peak Signal-to-Noise Ratio (PSNR). Our results confirm that the MPT-GRE tunnel effectively improves SSIM, PSNR, and reduces MSE compared to single-path streaming, offering a more stable, high-quality viewing experience. Our results indicate that analyzing the SSIM, MSE, and PSNR values for 4K video streaming using the MPT tunnel demonstrates a significant performance improvement compared to a single path. The improvement percentages of the SSIM and PSNR values for the MPT tunnel are (29.05% and 29.04%) higher than that of the single path, while MSE is reduced by 81.17% compared to the single path.

Open Access: Yes

DOI: 10.3390/electronics14030497

Equivalence and difference of the dual device under test setup and the single device under test setup of RFC 8219

Szabolcs Szilágyi Gábor Lencse

Publication Name: International Journal of Communication Systems

Publication Date: 2025-02-01

Volume: 38

Issue: 3

Page Range: Unknown

Description:

RFC 8219 has defined a comprehensive benchmarking methodology for the IPv6 transition technologies. It recommends two kinds of measurement setups: The dual device under test (DUT) setup facilitates the benchmarking of the customer edge (CE) and provider edge (PE) devices together using a legacy RFC 2544 or RFC 5180 Network Performance Tester, whereas the single DUT setup requires a separate technology-specific tester for the benchmarking of each device. As such, special-purpose testers do not exist for the vast majority of the IPv6 transition technologies; the only viable solution can be the usage of the dual DUT setup. In this paper, we investigate if the two kinds of measurement setups provide the same or different results; moreover, we examine how the single DUT measurement results can be estimated from the dual DUT measurement results. To that end, we make theoretical considerations and also perform IPv4 packet forwarding and stateless IP/ICMP translation (SIIT) measurements using both measurement setups and analyze the results of the throughput and latency measurements. It was found that the throughput results of the dual DUT setup could approximate well those of the single DUT setup and their differences followed the predictions of our theoretical considerations. However, the latency results did not always follow the theoretical expectations.

Open Access: Yes

DOI: 10.1002/dac.5982

IP Packet Forwarding Performance Comparison of the FD.io VPP and the Linux Kernel

Melinda Kosák Gábor Lencse

Publication Name: Infocommunications Journal

Publication Date: 2025-01-01

Volume: 17

Issue: 2

Page Range: 35-44

Description:

There are numerous free software solutions for IPv4 or IPv6 packet forwarding. The Fast Data Project / Vector Packet Processing (FD.io VPP) is a novel and prominent solution. This paper investigates its performance and scalability compared to that of the Linux kernel. The investigation was conducted in accordance with the requirements outlined in the relevant Request for Comments (RFC) documents (RFC 2544, RFC 4814, and RFC 5180) using the siitperf measurement software. Two different test environments were used to eliminate the potential hardware-specific side effects and to gain insight into the performance and scalability of the IPv4 and IPv6 packet forwarding capability of the two investigated solutions. It was found that FD.io VPP outperformed the Linux kernel by approximately an order of magnitude. The configuration of FD.io VPP, along with the details of the measurements, are provided, and the results are presented and analyzed in the paper.

Open Access: Yes

DOI: 10.36244/ICJ.2025.2.5

Performance Evaluation and Selection of Appropriate Congestion Control Algorithms for MPT Networks

Naseer Al-Imareen Gábor Lencse

Publication Name: International Journal of Advanced Computer Science and Applications

Publication Date: 2025-01-01

Volume: 16

Issue: 2

Page Range: 109-119

Description:

Recent academic research highlights a growing interest in multipath technologies, which offer promising solutions to networking challenges in complex environments. This interest is reflected in the emergence of protocols such as Multipath TCP (MPTCP) and Multipath UDP-in-GRE (MPT-GRE). The development of network protocols, particularly various iterations of the Transmission Control Protocol (TCP), has been distinguished by congestion detection and control algorithms, such as HighSpeed, CUBIC, Reno, LP, BBR, and Illinois. This paper evaluates the performance and suitability of these algorithms for multipath MPT-GRE networks under varying conditions, including delay, jitter, and data loss at different transmission speeds (both symmetric and asymmetric). Using StarBED resources, we applied delay, jitter, or packet loss to one of two physical paths to simulate congestion. The results demonstrate that some algorithms, HighSpeed and BBR among them, significantly enhance Quality of Service (QoS) metrics and network throughput in multipath MPT-GRE networks. These findings provide valuable insights into their performance and practical applications.

Open Access: Yes

DOI: 10.14569/IJACSA.2025.0160211

Making stateless and stateful network performance measurements unbiased

Gábor Lencse

Publication Name: Computer Communications

Publication Date: 2024-09-01

Volume: 225

Issue: Unknown

Page Range: 141-155

Description:

The Benchmarking Working Group (BMWG) of the Internet Engineering Task Force (IETF) has defined a series of Requests for Comments (RFC) to standardize the benchmarking of network interconnect devices (e.g., bridges, routers, different IPv6 transition solutions). The paper points out that there are cases where the performance results are significantly different when a single IP address pair or multiple IP addresses are used. The cause of this phenomenon is rooted in the recent hardware and software advancements: Receive Side Scaling (RSS) makes it possible to distribute packet processing workload over multiple CPU cores. However, this may be implemented in two ways: the first way only includes the IP addresses into the hash function used to distribute the workload among the CPU cores, whereas the second one also includes the port numbers. RFC 4814 proposed an excellent solution for the second case by recommending the usage of pseudorandom port numbers during benchmarking; however, the first case was not handled properly, because no explicit recommendation was given regarding the usage of multiple IP addresses. This paper attempts to bridge this methodological gap; a practical solution is proposed for using pseudorandom IP addresses in various scenarios including the benchmarking of IPv4 and IPv6 routers and Network Address Translation from IPv6 Clients to IPv4 Servers (stateful NAT64) gateways. Its feasibility is shown by disclosing the details of its implementation in siitperf. Then the proposed solution is validated by both stateless and stateful tests. It is shown that the measurement results of the tests following the proposed solution can better characterize the true performance of the network interconnect devices that follow the first type of RSS implementation than the results of the tests using a single IP address pair.

Open Access: Yes

DOI: 10.1016/j.comcom.2024.05.018

Benchmarking methodology for IPv4aaS technologies: Comparison of the scalability of the Jool implementation of 464XLAT and MAP-T

Ádám Bazsó Gábor Lencse

Publication Name: Computer Communications

Publication Date: 2024-04-01

Volume: 219

Issue: Unknown

Page Range: 243-258

Description:

A novel method is proposed for the performance and scalability measurements of the IPv4-as-a-Service (IPv4aaS) technologies. It works according to the dual Device Under Test (DUT) setup of RFC 8219 and is suitable for benchmarking any of the five IPv4aaS technologies: Combination of Stateful and Stateless Translation (464XLAT), Dual-Stack Lite (DS-Lite), Lightweight 4over6 (Lw4o6), Mapping of Address and Port with Encapsulation (MAP-E), and Mapping of Address and Port using Translation (MAP-T). The method is based on the reduction of the aggregate of Customer Edge (CE) and Provider Edge (PE) devices to a stateful network address translation from IPv4 to IPv4 (stateful NAT44) gateway. The most important advantage of the novel method is that a stateful NAT44 tester can be used instead of a technology-specific tester, which usually does not exist. The proposed method is validated by the examination of the performance and scalability of the Jool implementation of 464XLAT and MAP-T. Scalability is defined by both (1) how performance increases with the number of active Central Processing Unit (CPU) cores; and (2) how performance decreases with the increasing number of concurrent sessions. Maximum connection establishment rate and throughput are used as performance metrics. The scalability of 464XLAT and MAP-T is measured from 1 to 16 CPU cores and from 1 million to 256 million connections. The measurement details and results are fully disclosed and discussed.

Open Access: Yes

DOI: 10.1016/j.comcom.2024.03.007

On the Effectiveness of Congestion Control Algorithms on MPT-GRE Networks

Naseer Al-Imareen Gábor Lencse

Publication Name: 2024 47th International Conference on Telecommunications and Signal Processing Tsp 2024

Publication Date: 2024-01-01

Volume: Unknown

Issue: Unknown

Page Range: 87-91

Description:

Contemporary academic research is seeing a notable surge in interest in investigating the multifaceted aspects associated with the advancement of multipath technologies, an area of prominence within ongoing research efforts. This burgeoning interest is exemplified by the prominence of protocols such as Multipath TCP (MPTCP) and Multipath UDP (MPT), which have appeared as focal points within contemporary research trends. The continual evolution of networking protocols, containing diverse iterations of the Transmission Control Protocol (TCP), including (CUBIC, Reno, Vegas, BBR, etc.) has been characterized by a sustained effort to congestion detection and control algorithms. This paper demonstrates the effectiveness of TCP congestion control algorithms within a network operating under the MPT -GRE network layer multipath technology. Various factors contributing to congestion were added to one of the two paths, including delay or packet loss. The study illustrates the contribution of congestion control algorithms to the increase in network throughput by resolving transient period issues in MPT -GRE multipath networks. The main objective is to evaluate the effectiveness and efficiency of congestion control algorithms within the MPT network architecture. Through systematic analysis and experimental testing, this study provides valuable insights into the performance of congestion detection algorithms. It gives evidence of their significant positive effect in multipath MPT -GRE networks.

Open Access: Yes

DOI: 10.1109/TSP63128.2024.10605944

Performance Comparison of IP Packet Forwarding Solutions

Melinda Kosák Gábor Lencse

Publication Name: 2024 47th International Conference on Telecommunications and Signal Processing Tsp 2024

Publication Date: 2024-01-01

Volume: Unknown

Issue: Unknown

Page Range: 243-248

Description:

Nowadays we know several IP packet forwarding solutions, and they are getting faster and more efficient. We chose Fast Data Project / Vector Packet Processing (FD.io VPP) for our investigation, because it is regarded as an extremely high speed and secure networking data plane. In this paper, we present how to install and configure FD.io VPP and we also demonstrate its high IP packet forwarding performance compared to that of the Linux kernel. To achieve this, we built a testbed using two Dell PowerEdge R620 servers. One of the servers was the Tester and the siitperf measurement software was used for executing IPv4 and IPv6 packet forwarding performance tests. The other server was the DUT (Device Under Test), on which FD.io VPP was installed and its packet forwarding performance was measured. As a basis for comparison, we also measured the packet forwarding performance of the Linux kernel. It was found that FD.io VPP seriously outperformed the Linux kernel. The details of the measurements and their results are disclosed and analyzed in the paper.

Open Access: Yes

DOI: 10.1109/TSP63128.2024.10605773

Real-Time Video Streaming in MPT-GRE Multipath Networks

Naseer Al-Imareen Gábor Lencse

Publication Name: 2024 32nd International Conference on Software Telecommunications and Computer Networks Softcom 2024

Publication Date: 2024-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

Real-time video streaming over a multipath system enhances the quality of video delivery by diminishing packet loss, latency, and congestion, which eventually improves service quality and user experience. This paper addresses technical issues related to multipath routing, including path selection, packet scheduling, and path matching, and proposes solutions such as MPT-GRE. The effectiveness of MPT-GRE is assessed using recognized metrics such as PSNR, SSIM, and MSE, which are used to quantify differences in video quality. The paper aims to explore challenges and solutions in real-time video streaming over multipath networks, mainly focusing on MPT-GRE, while also quantitatively assessing the impact of streaming on video quality. In this paper, we selected a set of videos with different resolutions and specifications from the Waterloo Streaming QoE Database. The study measures how video quality assessment metrics influence streamed video through a network using the MPT-GRE communication library and demonstrates the efficiency of real-time video streaming using MPT-GRE. This paper presents evidence that MPT-GRE improves high-resolution video streaming, leading to a smoother and more reliable experience. These enhancements are validated using metrics such as PSNR, SSIM, and MSE, demonstrating the effectiveness of MPT-GRE in maintaining high video quality in multipath network environments.

Open Access: Yes

DOI: 10.23919/SoftCOM62040.2024.10721766

Benchmarking methodology for stateful NAT64 gateways

Keiichi Shima Kenjiro Cho Gábor Lencse

Publication Name: Computer Communications

Publication Date: 2023-10-01

Volume: 210

Issue: Unknown

Page Range: 256-272

Description:

The benchmarking of Network Address and Protocol Translation from IPv6 clients to IPv4 servers (stateful NAT64) gateways is challenging from a methodological point of view because the state of the art benchmarking standards have some requirements that are conflicting when applied to stateful NAT64 gateways. In this paper, several methodological gaps are pointed out and a benchmarking methodology is proposed, which is applicable for any stateful NATxy gateways, where x and y are in {4, 6}. It bridges all the gaps by reconciling the conflicting requirements and facilitating the execution of the industry standard benchmarking measurement procedures (throughput, latency, frame loss rate, packet delay variation) with stateful NATxy gateways. New performance metrics specific to stateful testing are also defined: maximum connection establishment rate, connection tear down rate, and connection tracking table capacity. The proposed methodology is suitable for examining the scalability of the stateful NATxy gateways, too. The methodology is validated by applying it to the benchmarking of three radically different stateful NAT64 implementations: Jool, tayga plus iptables, and OpenBSD Packet Filter (PF). The details of the measurements and their results are fully disclosed.

Open Access: Yes

DOI: 10.1016/j.comcom.2023.08.009

Effect of Path QoS on Throughput Aggregation Capability of the MPT Network Layer Multipath Communication Library

Naseer Al-Imareen Gábor Lencse

Publication Name: Infocommunications Journal

Publication Date: 2023-06-01

Volume: 15

Issue: 2

Page Range: 14-20

Description:

An increase in the use of smart and portable devices like smartphones, laptops, and tablets has led to a rise in the number of network interfaces and thus the number of possible channels for communication. However, the current approach over the Internet only employs a single path for a communication session. As an innovative and promising method for real-time transmission based on GRE-in-UDP encapsulation, which provides an IPv4 or IPv6 tunneling mechanism, this paper presents multipath throughput testing for the MPT network layer multipath communication library. We investigated the effectiveness of MPT's channel capacity aggregation while dealing with wired channels and examined scenarios in symmetric and asymmetric paths. Our network throughput measurements showed that MPT can efficiently aggregate the capacities of both symmetric and asymmetric paths. In this paper, we established a network topology that included a server, which we used for generating various quality of service (QoS) metrics. We measured how latency, transmission speed, packet loss rate, jitter, and the setting of the path weights influence throughput aggregation capability of the MPT communication library.

Open Access: Yes

DOI: 10.36244/ICJ.2023.2.3

On the Impact of Packet Reordering in MPT-GRE Multipath Networks

Naseer Al-Imareen Gábor Lencse

Publication Name: 2023 46th International Conference on Telecommunications and Signal Processing Tsp 2023

Publication Date: 2023-01-01

Volume: Unknown

Issue: Unknown

Page Range: 82-86

Description:

Several factors, such as network delays, congestion, differing path lengths, and varied processing durations at intermediary nodes, can cause out-of-order arrival of the packets, negatively affecting network performance, decreasing throughput, and increasing latency. When packets arrive out of order, the receiver may need to wait for missing packets before assembling a complete message, resulting in additional delays. Furthermore, some applications, like music and video streaming, require continuous and ordered data flow. Any out-of-order arrival of packets can result in jitter and decreased quality. To mitigate the impact of this issue in MPT-GRE multipath networks, MPT contains a packet reordering mechanism. In this paper, we designed a network topology that generated delays and limited the transmission speed on one of the paths. We investigated how the out-of-order arrival of packets influences the throughput aggregation capability of the MPT library with and without enabling the packet reordering feature of MPT. Our network throughput measurements show that by enabling MPT's packet reordering mechanism, MPT can efficiently aggregate the throughput of both symmetric and asymmetric channels.

Open Access: Yes

DOI: 10.1109/TSP59544.2023.10197737

Optimizing the Performance of the Iptables Stateful NAT44 Solution

Keiichi Shima Gábor Lencse

Publication Name: Infocommunications Journal

Publication Date: 2023-01-01

Volume: 15

Issue: 1

Page Range: 55-63

Description:

—The stateful NAT44 performance of iptables is an important issue when it is used as a stateful NAT44 gateway of a CGN (Carrier-Grade NAT) system. The performance measurements of iptables published in research papers do not comply with the requirements of RFC 2544 and RFC 4814 and the usability of their results has serious limitations. Our Internet Draft has proposed a benchmarking methodology for stateful NATxy (x, y are in {4, 6}) gateways and made it possible to perform the classic RFC 2544 measurement procedures like throughput, latency, frame loss rate, etc. with stateful NATxy gateways using RFC 4814 pseudorandom port numbers. It has also defined new performance metrics specific to stateful testing to quantify the connection setup and connection tear down performance of stateful NATxy gateways. In our current paper, we examine how the performance of iptables depends on various settings, and also if certain tradeoffs exist. We measure the maximum connection establishment rate, throughput and tear down rate of iptables as well as its memory consumption as a function of hash table size always using 40 million connections. We disclose all measurement details and results. We recommend new settings that enable network operators to achieve significantly higher performance than using the traditional ones.

Open Access: Yes

DOI: 10.36244/ICJ.2023.1.6

Design and implementation of a software tester for benchmarking stateful NATxy gateways: Theory and practice of extending siitperf for stateful tests

Gábor Lencse

Publication Name: Computer Communications

Publication Date: 2022-08-01

Volume: 192

Issue: Unknown

Page Range: 75-88

Description:

Our siitperf is the world's first RFC 8219 compliant free software SIIT (Stateless IP/ICMP Translation, also called stateless NAT64) benchmarking tool. It was written in C++ using DPDK (Intel Data Plane Development Kit). Our current effort aims to design and implement a test program for stateful NATxy gateways, including both stateful NAT64 and stateful NAT44 (also called NAPT: Network Address and Port Translation). Due to the object-oriented design of siitperf, it is feasible to extend it for stateful tests, while keeping its original design and features. In this paper, we introduce the problem of benchmarking stateful NATxy gateways and propose various solutions. We disclose the design and the most important implementation decisions of the stateful extension of siitperf. We prove the viability of our design and implementation by a functional NAT64 test and performing the maximum connection establishment rate, throughput, and frame loss rate measurements of the Jool stateful NAT64 implementation. We also carry out an initial performance estimation of the stateful extension of siitperf. Our tester is distributed as free software under the GPLv3 license for the benefit of the research, benchmarking and networking communities.

Open Access: Yes

DOI: 10.1016/j.comcom.2022.05.028

Measurement and Analysis of MPT Multipath Throughput in Wire Channels

Naseer A. Jabbar Gábor Lencse

Publication Name: International Conference on Electrical Computer Communications and Mechatronics Engineering Iceccme 2022

Publication Date: 2022-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

There is a significant growth in the use of the current intelligent and portable devices such as smartphones, laptops, and tablets that result in several network interfaces and various potential paths for communication. However, the mechanism used today via the Internet uses only one path for a communication session. This paper presents multipath throughput tests for the MPT network layer multipath communication library, a novel and promising solution for real-time transmission based on GRE-in-UDP encapsulation that provides an IPv4 or IPv6 tunneling (logical interface). We investigate the efficiency of channel capacity aggregation of MPT in dealing with physical paths via wired channels and test the cases when the physical paths have the same speed or radically different speeds.

Open Access: Yes

DOI: 10.1109/ICECCME55909.2022.9987956

Performance evaluation of DNS servers to build a benchmarking system of DNS64 implementations

Keiichi Shima Attila Pivoda Gábor Lencse

Publication Name: Telecommunication Systems

Publication Date: 2021-08-01

Volume: 77

Issue: 4

Page Range: 643-653

Description:

DNS64 is an important IPv6 transition technology that facilitates the communication of an IPv6 only client with an IPv4 only server, which becomes a more and more common scenario. Several different DNS64 implementations exist, and their performance is a relevant decision factor for network operators. RFC 8219 has defined a benchmarking methodology for DNS64 servers, which requires the operation of an authoritative DNS server at 220% of the query rate used for DNS64 benchmarking. In this paper, we aim to build an authoritative DNS server that operates at 2.2 million qps (queries per second) rate, thus it facilitates DNS64 benchmarking up to 1,000,000 qps rate. To that end, we compare the performance of BIND, YADIFA, NSD, Knot DNS and FakeDNS (a special purpose software) to find the best suiting one of them. We fully disclose the details of our measurements including the configuration of the DNS implementations, the usage of our improved software tester called dns64perf ++, and the details of the hardware and software measurement environment in the NICT StarBED, Japan. We perform a series of measurements to examine, how the performance of the tested solutions scale up with the number of the active CPU cores from 1 to 32. Besides their performance, we also measure their memory consumption and zone load time. We present and discuss all the results. In addition to successfully building an authoritative DNS server with the required performance, we also make recommendations, which solutions suit to different special needs.

Open Access: Yes

DOI: 10.1007/s11235-021-00780-3

Checking the accuracy of siitperf

Gábor Lencse

Publication Name: Infocommunications Journal

Publication Date: 2021-01-01

Volume: 13

Issue: 2

Page Range: 2-9

Description:

Siitperf is the world’s first free software RFC 8219 compliant SIIT (Stateless IP/ICMP Translation, also called as Stateless NAT64) tester, which implements throughput, frame loss rate, latency and packet delay variation tests. In this paper, we show that the reliability of its results mainly depends on the accuracy of the timing of its frame sender algorithm. We also investigate the effect of Ethernet flow control on the measurement results. Siitperf is calibrated by the comparison of its results with that of a commercial network performance tester, when both of them are used for determining the throughput of the IPv4 routing of the Linux kernel.

Open Access: Yes

DOI: 10.36244/ICJ.2021.2.1

Evaluation of layer 3 multipath solutions using container technologies

Akos Kovacs Gábor Lencse

Publication Name: 2019 42nd International Conference on Telecommunications and Signal Processing Tsp 2019

Publication Date: 2019-07-01

Volume: Unknown

Issue: Unknown

Page Range: 207-211

Description:

The MPT network layer multipath communication library is capable of using multiple communication channels by creating an UDP tunnel over them. The contemporary version of MPT uses the GRE tunnel protocol. MPTCP is another multipath solution, which uses TCP subflows on kernel level to ensure multipath communication. In this paper, we are using multiple container technologies to install these multipath communication solutions. Most common Docker container and a HPC specific Singularity container interconnected with twelve 100Mbit/s links were used to evaluate the aggregation capabilities of the combination of these technologies.

Open Access: Yes

DOI: 10.1109/TSP.2019.8768820

Methodology for DNS cache poisoning vulnerability analysis of DNS64 implementations

Gábor Lencse Y. Kadobayashi

Publication Name: Infocommunications Journal

Publication Date: 2018-06-01

Volume: 10

Issue: 2

Page Range: 13-25

Description:

The trustworthy operation of the DNS service is a very important precondition for a secure Internet. As we point it out, DNS cache poisoning could be even more dangerous if it is performed against DNS64 servers. Based on RFC 5452, we give an introduction to the three main components of DNS cache poisoning vulnerability, namely Transaction ID prediction, source port number prediction, and a birthday paradox based attack, which is possible if a DNS or DNS64 server sends out multiple equivalent queries (with identical QNAME, QTYPE, and QCLASS fields) concurrently. We design and implement a methodology and a testbed, which can be used for the systematic testing of DNS or DNS64 implementations, whether they are susceptible to these three vulnerabilities. We perform the tests with the following DNS64 implementations: BIND, PowerDNS, Unbound, TOTD (two versions) and mtd64-ng. As for the testbed, we use three virtual Linux machines executed by a Windows 7 host. As for tools, we use VMware Workstation 12 Player for virtualization, Wireshark and tshark for monitoring, dns64perf for Transaction ID and source port predictability tests, and our currently developed “birthday-test” program for concurrently sent multiple equivalent queries testing. Our methodology can be used for DNS cache poisoning vulnerability analysis of further DNS or DNS64 implementations. A testbed with the same structure may be used for security vulnerability analysis of DNS or DNS64 servers and also NAT64 gateways concerning further threats.

Open Access: Yes

DOI: DOI not available

Performance analysis and comparison of four DNS64 implementations under different free operating systems

Sándor Répás Gábor Lencse

Publication Name: Telecommunication Systems

Publication Date: 2016-12-01

Volume: 63

Issue: 4

Page Range: 557-577

Description:

The depletion of the global IPv4 address pool made the deployment of IPv6, the new version of the Internet Protocol, inevitable. In this paper, the transition mechanisms for the first phase of IPv6 deployment are surveyed and the DNS64 plus NAT64 solution is found appropriate. The most important free and open source DNS64 implementations are selected: BIND, TOTD, Unbound and PowerDNS. The test environment and the testing method are described. The first three of the selected DNS64 implementations are tested under Linux, OpenBSD and FreeBSD whereas PowerDNS is tested only under Linux. Their performance characteristics (response time, number of answered requests per second, CPU and memory consumption) are measured and compared. The effect of the hardware architecture of the test computer is also examined by using single-core, dual-core and quad-core test computers. The stability of all the tested DNS64 solutions are analyzed under overload conditions to test if they may be used in production environments with strong response time requirements. Our measurement results show significant differences in the performance of the tested DNS64 implementations, e.g. Unbound served four times more requests per second than PowerDNS (when executed by a single-core CPU under Linux and load was generated by eight clients). However, no absolute order can be determined, because it is influenced by different factors such as the architecture of the hardware, especially the number of cores, because BIND and PowerDNS are multithreaded (therefore they can profit from the multiple cores) but TOTD and Unbound are not. Also the operating system of the DNS64 server has significant influence on the performance of the DNS64 implementations under certain conditions. All the details of our measurements are disclosed and all the results are presented in the paper. An easy-to-use implementation selection guide is also provided as a short summary of our high number of results.

Open Access: Yes

DOI: 10.1007/s11235-016-0142-x

Stability analysis and performance comparison of five 6to4 relay implementations

Sándor Répás Viktor Horvath Gábor Lencse

Publication Name: Infocommunications Journal

Publication Date: 2016-06-01

Volume: 8

Issue: 2

Page Range: 1-10

Description:

Even though the present form of IPv6 has been existing since 1998, the adoption of the new protocol has been very slow until recently. To help the adoption of the IPv6 protocol, several transition technologies were introduced. The 6to4 protocol is one of them, and it can be used when an IPv6 enabled host resides in an IPv4 only environment and needs to communicate with other hosts in such circumstances or with native IPv6 hosts. Five open source 6to4 relay implementations were investigated: Debian Linux - sit, Debian Linux - v4tunnel, OpenWrt - sit, FreeBSD - stf, NetBSD - stf. The measurement method is fully described including our measurement scripts and the results of the measurements are disclosed in detail. The measurements have shown that there are major differences between the different types of implementations.

Open Access: Yes

DOI: DOI not available

Stability analysis and performance comparison of three 6to4 relay implementations

Sándor Répás Viktor Horvath Gábor Lencse

Publication Name: 2015 38th International Conference on Telecommunications and Signal Processing Tsp 2015

Publication Date: 2015-10-09

Volume: Unknown

Issue: Unknown

Page Range: 82-87

Description:

During the IPv6 deployment there is a frequently occurring situation where two IPv6 enabled hosts need to communicate with each other over a network that supports only IPv4. Application of the 6to4 IPv6 transition method can solve this problem. The performance and stability of the different 6to4 relay implementations is a very important subject. We measured the performance and tested the stability of three open source 6to4 relay implementations under Debian Linux, OpenBSD and OpenWRT platforms. We present and discuss our results, analyze the stability of the 6to4 relay implementations and compare their performance metrics. Our measurements methods may be useful for other researchers, and our results may help the system architects to choose the appropriate solution.

Open Access: Yes

DOI: 10.1109/TSP.2015.7296228

Modelling of virtualized servers

Akos Kovacs Gábor Lencse

Publication Name: 2015 38th International Conference on Telecommunications and Signal Processing Tsp 2015

Publication Date: 2015-10-09

Volume: Unknown

Issue: Unknown

Page Range: 421-425

Description:

The virtualized systems are one of the key elements of the next generation IT infrastructures. Modeling it will prevent mistakes, and oversized management. Opennebula is one of the most current open source cloud management solutions. Together with Haizea, they are a powerful tool to model and manage a virtualized infrastructure trough the API of Openebula. Haizea has multiple scheduler algorithms that are more effective than that of Opennebula. We performed several experiments to compare simulation and measurement capabilities of Haizea and we highlighted some difference between them which can be reduced if required.

Open Access: Yes

DOI: 10.1109/TSP.2015.7296296

Method for benchmarking single board computers for building a mini supercomputer for simulation of telecommunication systems

Sándor Répás Gábor Lencse

Publication Name: 2015 38th International Conference on Telecommunications and Signal Processing Tsp 2015

Publication Date: 2015-10-09

Volume: Unknown

Issue: Unknown

Page Range: 246-251

Description:

Parallel Discrete Event Simulation (PDES) with the conservative synchronization method can be efficiently used for the performance analysis of telecommunication systems because of their good lookahead properties. For PDES, a cost effective execution platform may be built by using single board computers (SBCs), which offer relatively high computation capacity compared to their price or power consumption and especially to the space they take up. A benchmarking method is proposed and its operation is demonstrated by benchmarking six different SBCs, namely Banana Pi, Beaglebone Black, Cubieboard2, Odroid-U3+, Radxa Rock Lite and Raspberry Pi Model B+. Their benchmarking results are compared to find out which one should be used for building a mini supercomputer for parallel discrete-event simulation of telecommunication systems. The SBCs are also used to build a heterogeneous cluster and the performance of the cluster is tested, too.

Open Access: Yes

DOI: 10.1109/TSP.2015.7296261

Modelling of virtualized servers

Akos Kovacs Gábor Lencse

Publication Name: 2015 38th International Conference on Telecommunications and Signal Processing Tsp 2015

Publication Date: 2015-10-09

Volume: Unknown

Issue: Unknown

Page Range: 241-245

Description:

The virtualized systems are one of the key elements of the next generation IT infrastructures. Modeling it will prevent mistakes, and oversized management. Opennebula is one of the most current open source cloud management solutions. Together with Haizea, they are a powerful tool to model and manage a virtualized infrastructure trough the API of Openebula. Haizea has multiple scheduler algorithms that are more effective than that of Opennebula. We performed several experiments to compare simulation and measurement capabilities of Haizea and we highlighted some difference between them which can be reduced if required.

Open Access: Yes

DOI: 10.1109/TSP.2015.7296260

Port number consumption of the NAT64 IPv6 transition technology

Sándor Répás Tamas Hajas Gábor Lencse

Publication Name: 2015 38th International Conference on Telecommunications and Signal Processing Tsp 2015

Publication Date: 2015-10-09

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

Due to the depletion of the global IPv4 address pool, the internet service providers will be able to supply their new clients with IPv6 addresses only in the near future. The application of the DNS64 and NAT64 technologies can enable the IPv6 only clients to communicate with the still dominant IPv4 only servers. However, the clients of certain applications such as HTTP and FTP use multiple sessions and thus they consume multiple ports. This phenomenon may cause a lack of ports situation at the NAT64 gateway. Therefore the port consumption of the different applications is an important design parameter of the NAT64 gateways. In this paper, the port consumption of different NAT64 compatible applications was measured. It was also determined what factors can influence the port consumption of a web or an ftp client. The detailed description of our measurement method is given. Our results can give a valuable help for careful design and configuration of a NAT64 gateway.

Open Access: Yes

DOI: 10.1109/TSP.2015.7296411

Application compatibility of the NAT64 IPv6 transition technology

Sándor Répás Tamas Hajas Gábor Lencse

Publication Name: 2015 38th International Conference on Telecommunications and Signal Processing Tsp 2015

Publication Date: 2015-10-09

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

The proliferation of smart phones and other Internet capable devices together with the depletion of the global IPv4 address pool will be a huge driving force for the deployment of IPv6 in the forthcoming years. The communication of an IPv6 only client with an IPv4 only server is a typical practical task to be solved among the many issues of the co-existence of IPv4 and IPv6. The usage of DNS64+NAT64 may be a good solution if our applications can flawlessly work with it. As for NAT64 implementations, TAYGA running under Linux and Packet Filter (PF) of OpenBSD were tested with the following application level protocols: HTTP, HTTPS, SMTP, POP3, IMAP4, Telnet, SSH, FTP, OpenVPN, RDP, Syslog, BitTorrent, Skype and SIP. The client-server application protocols could traverse through the NAT64 gateway flawlessly but the peer to peer ones failed. In contrast to the results of other researchers, OpenVPN worked perfectly with NAT64.

Open Access: Yes

DOI: 10.1109/TSP.2015.7296383

Estimation of the port number consumption of web browsing

Gábor Lencse

Publication Name: IEICE Transactions on Communications

Publication Date: 2015-08-01

Volume: E98B

Issue: 8

Page Range: 1580-1588

Description:

Due to the depletion of the public IPv4 address pool, Internet service providers will not be able to supply their new customers with public IPv4 addresses in the near future. Either they give private IPv4 addresses and use carrier grade NAT (CGN) or they move towards IPv6 and provide NAT64 service to the IPv6 only clients who want to reach IPv4 only servers. In both cases they must use a stateful NAT/NAT64 solution. When dimensioning a NAT/NAT64 gateway, the port number consumption of the clients is a key factor as the port numbers are 16 bits long and a unique one has to be provided for every session (when using traditional type NAPT, which does not include the destination IP address and port number in the tuple for the identification of TCP sessions) and a single web client may use several hundred sessions and an equal number of port numbers according to literature. In this paper, we present a method for the estimation of the port number consumption of web browsing. The method is based on the port number consumption measurements of the most popular web sites and their combination using the number of the visitors of the web sites as weight factors. We propose the resulting curve as an approximation of a general profile of the average port number consumption of web browsers after the first click, but without taking into consideration the effect of the web users' browsing behavior. We also discuss the case of the extended NAPT, which can reuse the source port numbers towards different destination IP addresses and/or destination port numbers. We propose a formula and give measurement results for the extended NAPT gateways, too. We disclose the measurement method in detail and provide the measurement scripts in Linux, too.

Open Access: Yes

DOI: 10.1587/transcom.E98.B.1580

Towards the efficient simulation of telecommunication systems in heterogeneous distributed execution environments

László Muka István Derka Gábor Lencse

Publication Name: 2013 36th International Conference on Telecommunications and Signal Processing Tsp 2013

Publication Date: 2013-10-21

Volume: Unknown

Issue: Unknown

Page Range: 304-310

Description:

An introduction is given to the topics of the parallel and distributed simulation and of the modeling of telecommunications systems. Our practical modeling concept for simulation in heterogeneous execution environment is presented. Its logical topology is a star shaped network of homogeneous clusters. The load balancing and the coupling factor criteria are set up for building models of telecommunications systems so that the simulation may produce good speed-up in a heterogeneous distributed execution environment. A case study is given with the open source OMNeT++ discrete-event simulation system and its parallel CQN (closed queueing network) sample model executed by 64 CPU cores of four different types. Our criteria are heavily supported by the results of our experiments. © 2013 IEEE.

Open Access: Yes

DOI: 10.1109/TSP.2013.6613941

Performance analysis and comparison of the TAYGA and of the PF NAT64 implementations

Sándor Répás Gábor Lencse

Publication Name: 2013 36th International Conference on Telecommunications and Signal Processing Tsp 2013

Publication Date: 2013-10-21

Volume: Unknown

Issue: Unknown

Page Range: 71-76

Description:

The transition mechanisms for the first phase of IPv6 deployment are surveyed and the most important NAT64 solutions are selected. The test environment and the testing method are described. As for the selected NAT64 implementations, the performance of the TAYGA running under Linux and of the Packet Filter (PF) of OpenBSD was measured and compared. The stability of the tested NAT64 solutions was analyzed under serious overload conditions to test if they may be used in production environments with strong response time requirements. © 2013 IEEE.

Open Access: Yes

DOI: 10.1109/TSP.2013.6613894

Performance analysis and comparison of different DNS64 implementations for Linux, OpenBSD and FreeBSD

Sándor Répás Gábor Lencse

Publication Name: Proceedings International Conference on Advanced Information Networking and Applications AINA

Publication Date: 2013-08-08

Volume: Unknown

Issue: Unknown

Page Range: 877-884

Description:

The transition mechanisms for the first phase of IPv6 deployment are surveyed and the most important DNS64 solutions are selected. The test environment and the testing method are described. As for the selected DNS64 implementations, the performance of both BIND9 and TOTD running under Linux, OpenBSD and FreeBSD are measured and compared. The stability of all the tested DNS64 solutions was analyzed under serious overload conditions to test if they may be used in production environments with strong response time requirements. © 2013 IEEE.

Open Access: Yes

DOI: 10.1109/AINA.2013.80

Investigation of the fault tolerance of the PIM-SM IP multicast routing protocol for IPTV purposes

István Derka Gábor Lencse

Publication Name: Infocommunications Journal

Publication Date: 2013-03-01

Volume: 5

Issue: 1

Page Range: 21-28

Description:

IPTV services should use an IP multicast solution for a network bandwidth efficient delivery of the media contents. PIM-SM is the most commonly used IP multicast routing protocol in IPTV systems. A short introduction to the operation of PIM-SM is given. Its fault tolerance is examined by experimenting on a mesh topology multicast test network built up by XORP routers in a virtualizcd environment. Different fault scenarios are played and different parameters of PIM-SM and OSPF are examined if they influence and how they influence the outage time of an IPTV service. A formal model is given for the service outage time of the IPTV service on the basis of the results of the experiments.

Open Access: Yes

DOI: DOI not available

Testing the speed-up of parallel discrete event simulation in heterogeneous execution environments

István Derka Gábor Lencse

Publication Name: 11th International Industrial Simulation Conference 2013 Isc 2013

Publication Date: 2013-01-01

Volume: Unknown

Issue: Unknown

Page Range: 101-107

Description:

This paper deals with the experimental testing and verification of the earlier proposed load balancing and coupling factor criteria for the conservative parallel discrete event simulation in heterogeneous execution environments whether they can ensure a good speed-up. The definition of the relative speed-up is extended to the heterogeneous systems in a natural way. This definition is used to measure the efficiency of the parallel simulation executed by heterogeneous systems. A closed queueing network is used as the simulation model, and it is executed on different heterogeneous test systems. Among several scenarios, it is demonstrated on the example of a heterogeneous system containing 87 CPU cores of 5 different types that a good speed-up can be achieved using the load balancing and coupling factor criteria. It is shown that the extension of the definition of the relative speed-up to the heterogeneous systems made it easy to judge the speed-up of parallel discrete event simulation in heterogeneous execution environments.

Open Access: Yes

DOI: DOI not available

Performance analysis of DNS64 and NAT64 solutions

Gábor Takács Gábor Lencse

Publication Name: Infocommunications Journal

Publication Date: 2012-06-01

Volume: 4

Issue: 2

Page Range: 29-36

Description:

The need for DNS64 and NAT64 solutions is introduced and their operation is presented. A test environment for the performance analysis of DNS64 and NAT64 implementations is described. The resource requirements of the implementations are measured. The performance of DNS64 and NAT64 solutions is measured under heavy load conditions to determine if they are safe to be used in a production environment, like the network of an internet service provider.

Open Access: Yes

DOI: DOI not available

Towards the modelling of the fault tolerance mechanism of the PIM-SM multicast routing protocol in an IPTV environment

István Derka Gábor Lencse

Publication Name: Esm 2012 2012 European Simulation and Modelling Conference Modelling and Simulation 2012

Publication Date: 2012-01-01

Volume: Unknown

Issue: Unknown

Page Range: 152-156

Description:

The fault tolerance mechanism of the PIM-SM IP multicast routing protocol is investigated in order to be able to model it. The analysis is done by playing different fault scenarios on a mesh topology multicast test network built up by XORP routers in a virtualized environment. Different parameters of the PIM-SM and the OSPF protocols are examined if they influence and how they influence the outage time of an IPTV service. The results of the experiments provide important factors for building a formal model of the service outage time of an IPTV service. © 2012 EUROSIS-ETI.

Open Access: Yes

DOI: DOI not available

Meta-level performance management of simulation of organizational information systems: The problem context state approach

László Muka Gábor Lencse

Publication Name: Infocommunications Journal

Publication Date: 2011-06-01

Volume: 3

Issue: 2

Page Range: 20-27

Description:

Simulation has become a frequently used tool for the analysis of ICT and BP systems and for fitting the features of these systems with each other and with the goals of the enterprise. For example, the change management of ERP (Enterprise Resource Planning) systems is a significant generator of the need for the common analysis of ICT/BP systems and the use of simulation may play crucial role in their analysis. The paper formulates the problem context state approach to the meta-level performance management of simulation in the form of efficiency management principles. The formulation is based on the investigation of the features of the dynamic behavior of problem contexts - using the 4-state and 2-state models of problem context types - for the common modeling and simulation of organizational ICT/BP systems. The process of the occurrence and elimination of the methodological gap is explained too.

Open Access: Yes

DOI: DOI not available

Performance prediction of conservative parallel discrete event simulation

Andras Varga Gábor Lencse

Publication Name: 8th International Industrial Simulation Conference 2010 Isc 2010

Publication Date: 2010-01-01

Volume: Unknown

Issue: Unknown

Page Range: 214-219

Description:

In a previous paper, a quantitative criterion has been proposed for efficient execution of the Null Message Protocol, the best-known conservative parallel discrete event simulation (PDES) protocol. The criterion is based on a novel concept of the coupling factor, and allows one to use intuitive and easy-to-measure input parameters. The criterion can be used to assess simulation models' potential for parallel execution as well as the maximum partitioning that may still potentially yield good performance. This paper deals with experimental verification of the proposed rule that a large coupling factor is a necessary precondition for getting a good speed-up with conservative parallel simulation. A closed queueing network is used as simulation model, and it is run on up to 24 CPU cores. It is shown that the criterion provides a quick and convenient way to determine whether a simulation model has a potential for speed-up before actually investing work in the parallelization.

Open Access: Yes

DOI: DOI not available

Cooperating modelling methods for performance evaluation of interconnected infocommunication and business process systems

László Muka Gábor Lencse

Publication Name: Esm 2008 2008 European Simulation and Modelling Conference Modelling and Simulation 2008

Publication Date: 2008-01-01

Volume: Unknown

Issue: Unknown

Page Range: 404-411

Description:

This paper describes how the rapid and detailed modelling and simulation methods can be used to increase the efficiency of mixed simulation projects initiated to support the design of interconnected ICT (Information and Communication Technology) and BP (Business Process) systems. A system of cooperating rapid and detailed methods for critical and non- critical parts of systems is introduced in the phase of preliminary and detailed modelling. The method of translation of information of conceptual models that had been built prior to simulation is described, too. New methods using rapid models to model the ICT and BP systems functioning as environment for the detailed models are presented. A novel method for preliminary modelling based only on cooperating system of rapid models is described. © 2008 EUROSIS-ETI.

Open Access: Yes

DOI: DOI not available

Managing the resolution of simulation models

László Muka Gábor Lencse

Publication Name: Esm 2008 2008 European Simulation and Modelling Conference Modelling and Simulation 2008

Publication Date: 2008-01-01

Volume: Unknown

Issue: Unknown

Page Range: 38-42

Description:

A novel approach based on inflation and deflation is proposed for managing the resolution of simulation models. Different methods are proposed for manual or automatic deflation. An example is given how a topology description language can be extended to support the inflation/deflation concept. Dynamic management of the model resolution is introduced using the method called inflate-the-next and also two of its possible improvements. © 2008 EUROSIS-ETI.

Open Access: Yes

DOI: DOI not available

Combination and interworking of four modelling methods for infocommunications and business process systems

László Muka Gábor Lencse

Publication Name: 5th International Industrial Simulation Conference 2007 Isc 2007

Publication Date: 2007-01-01

Volume: Unknown

Issue: Unknown

Page Range: 350-354

Description:

This paper describes how we can use four modelling methods together. We model Information and Communication Technology (ICT) systems and Business Process (BP) systems. The aim of the modelling is to experiment with the models, that is, simulation. Two of the methods are the detailed modelling of the ICT and of the BP systems, as we usually do that for discrete event simulation. The other two methods are those that enable us to make rapid performance analysis of these systems, namely Traffic-Flow Analysis (TEA) for ICT systems and Entity Flow-phase Analysis (EFA) for BP systems. The solutions for the combination and interworking of these methods are described.

Open Access: Yes

DOI: DOI not available

Investigation of the spatial distribution algorithm of the traffic flow analysis and of the entity flow-phase analysis

László Muka Gábor Lencse

Publication Name: Esm 2007 2007 European Simulation and Modelling Conference Modelling and Simulation 2007

Publication Date: 2007-01-01

Volume: Unknown

Issue: Unknown

Page Range: 291-295

Description:

This paper investigates an important algorithm that is used in both the Traffic-Flow Analysis and the Entity Flow-phase Analysis. These methods are similar to each other and can be used for the fast and approximate (performance) analysis of Information and Communication Technology (ICT) systems and Business Process (BP) systems. Both methods contain an algorithm for the spatial distribution of the traffic (or entities) in the system. It is shown how the error of the spatial distribution can be measured, and the effect of the so called size of routing unit parameter of two algorithms is investigated.

Open Access: Yes

DOI: DOI not available

Convergence of the key algorithm of traffic-flow analysis

László Muka Gábor Lencse

Publication Name: Journal of Computing and Information Technology

Publication Date: 2006-01-01

Volume: 14

Issue: 2

Page Range: 133-139

Description:

The traffic-flow analysis (TFA) [1] is a novel method for the performance estimation of communication systems. TFA is a combination of simulation and numerical methods. In the first step, TFA distributes the traffic in units of properly chosen size using the actual routing algorithm of the network. In the second step, TFA adjusts the time distribution of the traffic according to the finite capacities of the network. The convergence of the algorithm used in the second step of TFA is proven in this paper. The speed of convergence is also examined.

Open Access: Yes

DOI: 10.2498/cit.2006.02.04

Expanded scope of traffic-flow analysis: Entity flow-phase analysis for rapid performance evaluation of enterprise process systems

László Muka Gábor Lencse

Publication Name: Esm 2006 2006 European Simulation and Modelling Conference Modelling and Simulation 2006

Publication Date: 2006-01-01

Volume: Unknown

Issue: Unknown

Page Range: 94-98

Description:

This paper describes entity-flow phase analysis (EFA) which is a method for fast performance analysis of organisational process systems. EFA, similarly to traffic-flow analysis for communication systems (TFA), uses the combined approach of simulation and numerical methods. In simulation projects initiated to support the design of Information and Communication Technology (ICT) system and Business Process (BP) system in an organisation the parallel analysis of different systems may be efficient. EFA is a promising evaluation method to be applied for systems with determined BP and ICT subsystems in an organisational environment.

Open Access: Yes

DOI: DOI not available

Speeding up the performance analysis of communication systems

Gábor Lencse

Publication Name: 2005 European Simulation and Modelling Conference Esm 2005 Proceedings

Publication Date: 2005-01-01

Volume: Unknown

Issue: Unknown

Page Range: 329-333

Description:

The methods for the performance analysis of communication networks are reviewed. Different ways are shown how the combination of DES and TFA can be made faster by using parallelism. An efficient algorithm for the parallel execution of the combined DES and TFA is presented.

Open Access: Yes

DOI: DOI not available

Traffic-flow analysis for fast performance estimation of communication systems

Gábor Lencse

Publication Name: Journal of Computing and Information Technology

Publication Date: 2001-01-01

Volume: 9

Issue: 1

Page Range: 15-27

Description:

The traffic-flow analysis (TFA) is a promising method for the performance estimation of communication systems. TFA produces approximate results with much less computation (that is, much faster) than discrete-event simulation of the system. In the first step, TFA distributes the traffic in units of properly chosen size using the actual routing algorithm of the network. In the second step, TFA adjusts the time distribution of the traffic according to the finite capacities of the network. It was found that the results of TFA approximate the results of the analytical method well.

Open Access: Yes

DOI: 10.2498/cit.2001.01.02