Sándor Répás

55811595800

Publications - 11

Performance Analysis of Encryption Capabilities of ARM-based Single Board Microcomputers

Sándor Répás

Publication Name: Infocommunications Journal

Publication Date: 2023-06-01

Volume: 15

Issue: 2

Page Range: 8-13

Description:

In the few years since the Raspberry Pi was released in 2012, countless microcomputers based on the ARM architecture have been introduced. Their small size, high performance relative to their power consumption, and the ability to run the popular Linux operating system make them ideal for a wide range of tasks. Information security is an area of particular importance. Different encryption and encoding algorithms play an important role in almost all areas of information security. However, these algorithms are very computationally intensive, so it is important to investigate which microcomputers can be used for these tasks, and under which trade-offs. The performance of ten different microcomputers is investigated and presented for the application of common symmetric and public-key encryption and decryption, digest creation and message authentication protocols, such as RSA, AES, HMAC, MD5, SHA. Reliable encryption requires the generation of reliable (pseudo)random numbers (Cryptographically Secure Random Numbers, CSRN), and microcomputers based on ARM SoCs usually have hardware implemented (pseudo)random number generators. The applicability of the random number generators of different microcomputers are investigated and presented; test methods are described, and recommendations are made.

Open Access: Yes

DOI: 10.36244/ICJ.2023.2.6

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

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

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

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

DDOS Attack Mitigation Based on FPGA Implementation

Sándor Répás Ahmed Jamal Ibrahim

Publication Name: International Conference on Electrical Computer and Energy Technologies Icecet 2024

Publication Date: 2024-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

With the widespread use of computer networks daily, network security has become a significant problem in the new technology era. Due to the quick growth of the World Wide Web, it is becoming more challenging for researchers to find new methods to prevent attackers from reaching their targets. The spread of malicious cyber network activity poses a significant risk to numerous organizations and inflicts substantial economic consequences on society. Distributed Denial of Service (DDoS) is a cyberattack technique that disrupts the regular traffic of the target server or system by flooding it with an abnormal flow of internet traffic from different sources. The current article explores the advantages of FPGA-based devices in network security to mitigate the effects of DDoS attacks.

Open Access: Yes

DOI: 10.1109/ICECET61485.2024.10698517

The Impact of Diverse Gateway Implementations on Mesh Network Performance

Jitka Komarkova Tawfik Al-Hadhrami Sándor Répás Ibrahim Alameri Ahmed Jamal Ibrahim Elmustafa Sayed Ali

Publication Name: Lecture Notes on Data Engineering and Communications Technologies

Publication Date: 2026-01-01

Volume: 263

Issue: Unknown

Page Range: 27-38

Description:

Wireless Mesh Networks (WMNs) provide seamless connectivity in rapidly changing and dense environments. But when gateways are integrated to provide network access from outside the current topology, several issues become problems. These include maintaining high levels of performance, energy efficiency, security awareness and interconnection. Traditional routing protocols such as Ad hoc On-Demand Distance Vector Routing (AODV) were not able to achieve these two purposes at all in a hybrid setting where efficient communication with the gateway was needed, especially when faced with high mobility, node density and changing traffic loads. This paper introduces that the problem can be resolved by implementing Fuzzy Control Energy Efficient (FCEE) routing in WMNs The FCEE routing method, characteristic innovative energy-efficient real-time failure mechanism and overall network performance enhancement for wireless mesh networks By integrating fuzzy logic into the AODV framework, the FCEE method adds a short-term memory module that optimizes packet broadcasts based on real-time levels of energy available to each node. The FCEE method not only enhances decision-making for packet forwarding but also reduces unwanted broadcasts thus extending the life of the entire network. Simulations show the FCEE performs better than traditional methods in terms of both energy efficiency, congestion control, and adaptability to dynamic situations. The proposed method thus provides an affordable way to improve the operation of wireless mesh networks, particularly in the case of high traffic areas or long periods where resources are constrained.

Open Access: Yes

DOI: 10.1007/978-3-032-01005-6_3