Contents:
Introduction
Architecture
MAC Sublayer
Distribution Coordination Function
Point Coordination Function
MAC Layer Frame
Physical Layer
IEEE 802.11 FHSS
IEEE 802.11 DSSS
IEEE 802.11 Infrared
Contents:
Introduction
Architecture
MAC Sublayer
Distribution Coordination Function
Point Coordination Function
MAC Layer Frame
Physical Layer
IEEE 802.11 FHSS
IEEE 802.11 DSSS
IEEE 802.11 Infrared
In this talk, we will explain the functioning of Wireless LANs in theory and in practice.
We will present the IEEE 802.11 standard in general and MAC protocols in particular, by discussing the functions of MAC sublayer management entity and the MAC layer frames in detail.
We will discuss the changes in the states of a WiFi client as it goes through the process of WiFi communication.
Towards the end, we will briefly talk about various vantage points ( at the client side as well as in the air ) that allow us to capture network traffic.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
NetSim VANET library (https://www.tetcos.com) supports the following protocols
IEEE 802.11p, IEEE 1609 WAVE
Layer 3 Routing – AODV, DSR, OLSR, ZRP
PHY Layer RF Propagation
o Pathloss
o Shadowing
o Fading
Source C Code
Automatic import of road network and vehicles from SUMO
Wide range of output metrics including Delay, Throughput, Error, Retransmission,
etc.
Interfacing between SUMO & NetSim via Traffic control interface (TraCI).
In this talk, we will explain the functioning of Wireless LANs in theory and in practice.
We will present the IEEE 802.11 standard in general and MAC protocols in particular, by discussing the functions of MAC sublayer management entity and the MAC layer frames in detail.
We will discuss the changes in the states of a WiFi client as it goes through the process of WiFi communication.
Towards the end, we will briefly talk about various vantage points ( at the client side as well as in the air ) that allow us to capture network traffic.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
NetSim VANET library (https://www.tetcos.com) supports the following protocols
IEEE 802.11p, IEEE 1609 WAVE
Layer 3 Routing – AODV, DSR, OLSR, ZRP
PHY Layer RF Propagation
o Pathloss
o Shadowing
o Fading
Source C Code
Automatic import of road network and vehicles from SUMO
Wide range of output metrics including Delay, Throughput, Error, Retransmission,
etc.
Interfacing between SUMO & NetSim via Traffic control interface (TraCI).
Impact of Randomness on MAC Layer Schedulers over High Speed Wireless Campus ...ijcsse
IEEE802.11e standard provides an EDCA mechanism to ensure the QoS using service differentiation function for IMM traffics through the WCN. In an EDCA mechanism, IMM traffics have been classified into four categories and each category has specific priority. Many EDCA schedulers allow these traffics to access the channel based on assigned priorities. The IMM high priority traffic is high delay sensitive and required high bandwidth to ensure QoS over the networks. Scheduling mechanism is the effective way to satisfy IMM traffic but it cannot give guarantee because of the randomness of some EDCA schedulers or proposed networks. In order to provide the QoS, scheduling mechanism is the challenging issue to transmit IMM traffic through the channel and it is still need to be solved over WCN. This work aims to examine the effect of the randomness on different MAC layer schedulers' performance and evaluates the performance of the proposed schedulers using different performance metrics in WCN.
Ns 2 based simulation environment for performance evaluation of umts architec...Makhdoom Waseem Hashmi
Ns 2 based simulation environment for performance evaluation of umts architecture.
NS2, UMTS, 3G, EURANE, scheduling, architecture and umts simultation and NS2 simulation and EURANE SIMULATION
INVESTIGATION AND EVALUATION OF IEEE 802.11N WLANS LINK FEATURES PERFORMANCE ...pijans
For an efficient design of wireless local-area networks (WLANs), the simulation tools are important to accurately estimate the IEEE 802.11n/ac link features for WLANs. However, this true simulation of network behavior is critical in designing high-performance WLANs. Through testing, analysis, and modeling of the proposed scheme repetitively, the design of the WLAN can be enhanced with a small budget before making its practical implementation. Many network simulation tools have been established to give solutions for this request and ns-3 is the most widely used tools among them by the research industry as an open-source network simulator. In this paper, we examine the various link features of the 802.11n WLANs under several conditions. We investigate the effects of 802.11n WLAN modulation and coding schemes (MCSs), 20MHz single channel or 40 MHz bonded channel, guard intervals (GI), frame aggregation, data encoding, number of antennas and their data rate, and link distance features of 802.11n WLAN in ns-3 when only a unique host connects with the access point (AP) and generates data traffic. Besides, the performance for an enterprise scenario proposed by the IEEE 802.11ax study group is evaluated when several hosts are simultaneously creating traffic with their associated APs. The results demonstrate that ns-3 support most of the link features of the 802.11n protocol with significant accuracy.
Investigation and Evaluation of IEEE 802.11n WLANs Link Features Performance ...pijans
For an efficient design of wireless local-area networks (WLANs), the simulation tools are important to accurately estimate the IEEE 802.11n/ac link features for WLANs. However, this true simulation of network behavior is critical in designing high-performance WLANs. Through testing, analysis, and modeling of the proposed scheme repetitively, the design of the WLAN can be enhanced with a small budget before making its practical implementation. Many network simulation tools have been stablished to give solutions for this request and ns-3 is the most widely used tools among them by the research industry as an open-source network simulator. In this paper, we examine the various link features of the 802.11n WLANs under several conditions. We investigate the effects of 802.11n WLAN modulation and coding schemes (MCSs), 20MHz single channel or 40 MHz bonded channel, guard intervals (GI), frame aggregation, data encoding, number of antennas and their data rate, and link distance features of 802.11n WLAN in ns-3 when only a unique host connects with the access point (AP) and generates data traffic. Besides, the performance for an enterprise scenario proposed by the IEEE 802.11ax study group is evaluated when several hosts are simultaneously creating traffic with their associated APs. The results demonstrate that ns-3 support most of the link features of the 802.11n protocol with significant accuracy
Investigation and Evaluation of IEEE 802.11n Wlans Link Features Performance ...pijans
For an efficient design of wireless local-area networks (WLANs), the simulation tools are important to accurately estimate the IEEE 802.11n/ac link features for WLANs. However, this true simulation of network behavior is critical in designing high-performance WLANs. Through testing, analysis, and modeling of the proposed scheme repetitively, the design of the WLAN can be enhanced with a small budget before making its practical implementation. Many network simulation tools have been established to give solutions for this request and ns-3 is the most widely used tools among them by the research industry as an open-source network simulator. In this paper, we examine the various link features of the 802.11n WLANs under several conditions. We investigate the effects of 802.11n WLAN modulation and coding schemes (MCSs), 20MHz single channel or 40 MHz bonded channel, guard intervals (GI), frame aggregation, data encoding, number of antennas and their data rate, and link distance features of 802.11n WLAN in ns-3 when only a unique host connects with the access point (AP) and generates data traffic. Besides, the performance for an enterprise scenario proposed by the IEEE 802.11ax study group is evaluated when several hosts are simultaneously creating traffic with their associated APs. The results demonstrate that ns-3 support most of the link features of the 802.11n protocol with significant accuracy.
Implementation model architecture software defined network using raspberry Pi...TELKOMNIKA JOURNAL
Software defined network (SDN) made with basic concepts that are different from traditional networks in controlling the network, the separation between the control layer and forwarding layer on different devices allows the administrator to adjust the control plan for all devices centralized in one action, while in traditional network, the control and forwarding layers are located in the infrastructure making network administrator must manage devices one by one. Research using single board computers on network technology provides an opportunity to implement SDN architecture. Raspberry Pi has sufficient ability. QoS results meet the ITU-T G.1010 reference which indicates that Raspberry Pi can be used on designed networks.
The peer-reviewed International Journal of Engineering Inventions (IJEI) is started with a mission to encourage contribution to research in Science and Technology. Encourage and motivate researchers in challenging areas of Sciences and Technology.
Observability Concepts EVERY Developer Should Know -- DeveloperWeek Europe.pdfPaige Cruz
Monitoring and observability aren’t traditionally found in software curriculums and many of us cobble this knowledge together from whatever vendor or ecosystem we were first introduced to and whatever is a part of your current company’s observability stack.
While the dev and ops silo continues to crumble….many organizations still relegate monitoring & observability as the purview of ops, infra and SRE teams. This is a mistake - achieving a highly observable system requires collaboration up and down the stack.
I, a former op, would like to extend an invitation to all application developers to join the observability party will share these foundational concepts to build on:
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
Le nuove frontiere dell'AI nell'RPA con UiPath Autopilot™UiPathCommunity
In questo evento online gratuito, organizzato dalla Community Italiana di UiPath, potrai esplorare le nuove funzionalità di Autopilot, il tool che integra l'Intelligenza Artificiale nei processi di sviluppo e utilizzo delle Automazioni.
📕 Vedremo insieme alcuni esempi dell'utilizzo di Autopilot in diversi tool della Suite UiPath:
Autopilot per Studio Web
Autopilot per Studio
Autopilot per Apps
Clipboard AI
GenAI applicata alla Document Understanding
👨🏫👨💻 Speakers:
Stefano Negro, UiPath MVPx3, RPA Tech Lead @ BSP Consultant
Flavio Martinelli, UiPath MVP 2023, Technical Account Manager @UiPath
Andrei Tasca, RPA Solutions Team Lead @NTT Data
zkStudyClub - Reef: Fast Succinct Non-Interactive Zero-Knowledge Regex ProofsAlex Pruden
This paper presents Reef, a system for generating publicly verifiable succinct non-interactive zero-knowledge proofs that a committed document matches or does not match a regular expression. We describe applications such as proving the strength of passwords, the provenance of email despite redactions, the validity of oblivious DNS queries, and the existence of mutations in DNA. Reef supports the Perl Compatible Regular Expression syntax, including wildcards, alternation, ranges, capture groups, Kleene star, negations, and lookarounds. Reef introduces a new type of automata, Skipping Alternating Finite Automata (SAFA), that skips irrelevant parts of a document when producing proofs without undermining soundness, and instantiates SAFA with a lookup argument. Our experimental evaluation confirms that Reef can generate proofs for documents with 32M characters; the proofs are small and cheap to verify (under a second).
Paper: https://eprint.iacr.org/2023/1886
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
Pushing the limits of ePRTC: 100ns holdover for 100 daysAdtran
At WSTS 2024, Alon Stern explored the topic of parametric holdover and explained how recent research findings can be implemented in real-world PNT networks to achieve 100 nanoseconds of accuracy for up to 100 days.
Elevating Tactical DDD Patterns Through Object CalisthenicsDorra BARTAGUIZ
After immersing yourself in the blue book and its red counterpart, attending DDD-focused conferences, and applying tactical patterns, you're left with a crucial question: How do I ensure my design is effective? Tactical patterns within Domain-Driven Design (DDD) serve as guiding principles for creating clear and manageable domain models. However, achieving success with these patterns requires additional guidance. Interestingly, we've observed that a set of constraints initially designed for training purposes remarkably aligns with effective pattern implementation, offering a more ‘mechanical’ approach. Let's explore together how Object Calisthenics can elevate the design of your tactical DDD patterns, offering concrete help for those venturing into DDD for the first time!
PHP Frameworks: I want to break free (IPC Berlin 2024)Ralf Eggert
In this presentation, we examine the challenges and limitations of relying too heavily on PHP frameworks in web development. We discuss the history of PHP and its frameworks to understand how this dependence has evolved. The focus will be on providing concrete tips and strategies to reduce reliance on these frameworks, based on real-world examples and practical considerations. The goal is to equip developers with the skills and knowledge to create more flexible and future-proof web applications. We'll explore the importance of maintaining autonomy in a rapidly changing tech landscape and how to make informed decisions in PHP development.
This talk is aimed at encouraging a more independent approach to using PHP frameworks, moving towards a more flexible and future-proof approach to PHP development.
State of ICS and IoT Cyber Threat Landscape Report 2024 previewPrayukth K V
The IoT and OT threat landscape report has been prepared by the Threat Research Team at Sectrio using data from Sectrio, cyber threat intelligence farming facilities spread across over 85 cities around the world. In addition, Sectrio also runs AI-based advanced threat and payload engagement facilities that serve as sinks to attract and engage sophisticated threat actors, and newer malware including new variants and latent threats that are at an earlier stage of development.
The latest edition of the OT/ICS and IoT security Threat Landscape Report 2024 also covers:
State of global ICS asset and network exposure
Sectoral targets and attacks as well as the cost of ransom
Global APT activity, AI usage, actor and tactic profiles, and implications
Rise in volumes of AI-powered cyberattacks
Major cyber events in 2024
Malware and malicious payload trends
Cyberattack types and targets
Vulnerability exploit attempts on CVEs
Attacks on counties – USA
Expansion of bot farms – how, where, and why
In-depth analysis of the cyber threat landscape across North America, South America, Europe, APAC, and the Middle East
Why are attacks on smart factories rising?
Cyber risk predictions
Axis of attacks – Europe
Systemic attacks in the Middle East
Download the full report from here:
https://sectrio.com/resources/ot-threat-landscape-reports/sectrio-releases-ot-ics-and-iot-security-threat-landscape-report-2024/
Encryption in Microsoft 365 - ExpertsLive Netherlands 2024Albert Hoitingh
In this session I delve into the encryption technology used in Microsoft 365 and Microsoft Purview. Including the concepts of Customer Key and Double Key Encryption.
DevOps and Testing slides at DASA ConnectKari Kakkonen
My and Rik Marselis slides at 30.5.2024 DASA Connect conference. We discuss about what is testing, then what is agile testing and finally what is Testing in DevOps. Finally we had lovely workshop with the participants trying to find out different ways to think about quality and testing in different parts of the DevOps infinity loop.
Why You Should Replace Windows 11 with Nitrux Linux 3.5.0 for enhanced perfor...SOFTTECHHUB
The choice of an operating system plays a pivotal role in shaping our computing experience. For decades, Microsoft's Windows has dominated the market, offering a familiar and widely adopted platform for personal and professional use. However, as technological advancements continue to push the boundaries of innovation, alternative operating systems have emerged, challenging the status quo and offering users a fresh perspective on computing.
One such alternative that has garnered significant attention and acclaim is Nitrux Linux 3.5.0, a sleek, powerful, and user-friendly Linux distribution that promises to redefine the way we interact with our devices. With its focus on performance, security, and customization, Nitrux Linux presents a compelling case for those seeking to break free from the constraints of proprietary software and embrace the freedom and flexibility of open-source computing.
Dev Dives: Train smarter, not harder – active learning and UiPath LLMs for do...UiPathCommunity
💥 Speed, accuracy, and scaling – discover the superpowers of GenAI in action with UiPath Document Understanding and Communications Mining™:
See how to accelerate model training and optimize model performance with active learning
Learn about the latest enhancements to out-of-the-box document processing – with little to no training required
Get an exclusive demo of the new family of UiPath LLMs – GenAI models specialized for processing different types of documents and messages
This is a hands-on session specifically designed for automation developers and AI enthusiasts seeking to enhance their knowledge in leveraging the latest intelligent document processing capabilities offered by UiPath.
Speakers:
👨🏫 Andras Palfi, Senior Product Manager, UiPath
👩🏫 Lenka Dulovicova, Product Program Manager, UiPath
A tale of scale & speed: How the US Navy is enabling software delivery from l...sonjaschweigert1
Rapid and secure feature delivery is a goal across every application team and every branch of the DoD. The Navy’s DevSecOps platform, Party Barge, has achieved:
- Reduction in onboarding time from 5 weeks to 1 day
- Improved developer experience and productivity through actionable findings and reduction of false positives
- Maintenance of superior security standards and inherent policy enforcement with Authorization to Operate (ATO)
Development teams can ship efficiently and ensure applications are cyber ready for Navy Authorizing Officials (AOs). In this webinar, Sigma Defense and Anchore will give attendees a look behind the scenes and demo secure pipeline automation and security artifacts that speed up application ATO and time to production.
We will cover:
- How to remove silos in DevSecOps
- How to build efficient development pipeline roles and component templates
- How to deliver security artifacts that matter for ATO’s (SBOMs, vulnerability reports, and policy evidence)
- How to streamline operations with automated policy checks on container images
Removing Uninteresting Bytes in Software FuzzingAftab Hussain
Imagine a world where software fuzzing, the process of mutating bytes in test seeds to uncover hidden and erroneous program behaviors, becomes faster and more effective. A lot depends on the initial seeds, which can significantly dictate the trajectory of a fuzzing campaign, particularly in terms of how long it takes to uncover interesting behaviour in your code. We introduce DIAR, a technique designed to speedup fuzzing campaigns by pinpointing and eliminating those uninteresting bytes in the seeds. Picture this: instead of wasting valuable resources on meaningless mutations in large, bloated seeds, DIAR removes the unnecessary bytes, streamlining the entire process.
In this work, we equipped AFL, a popular fuzzer, with DIAR and examined two critical Linux libraries -- Libxml's xmllint, a tool for parsing xml documents, and Binutil's readelf, an essential debugging and security analysis command-line tool used to display detailed information about ELF (Executable and Linkable Format). Our preliminary results show that AFL+DIAR does not only discover new paths more quickly but also achieves higher coverage overall. This work thus showcases how starting with lean and optimized seeds can lead to faster, more comprehensive fuzzing campaigns -- and DIAR helps you find such seeds.
- These are slides of the talk given at IEEE International Conference on Software Testing Verification and Validation Workshop, ICSTW 2022.
Smart TV Buyer Insights Survey 2024 by 91mobiles.pdf91mobiles
91mobiles recently conducted a Smart TV Buyer Insights Survey in which we asked over 3,000 respondents about the TV they own, aspects they look at on a new TV, and their TV buying preferences.
Smart TV Buyer Insights Survey 2024 by 91mobiles.pdf
The NCTUns 5.0 Network Simulator
1. The NCTUns 5.0 Network Simulator and Emulator
INTRODUCTION
The NCTUns network simulator and emulator [1][2] is a valuable tool for network research, planning,
and education. It is an open-source software running on Linux and provides an easy-to-use integrated
GUI environment for users to efficiently conduct simulations/emulations. Many research institutes,
industry companies, and universities are using it for various purposes. The authors of many journal
papers, conference
papers, Ph.D. dissertations, master theses, etc. have used it to conduct researches. By adopting an
innovative kernel re-entering simulation methodology [4], NCTUns provides many unique and
important advantages over traditional network simulators and emulators. For example, NCTUns
directly uses the real-life TCP/IP protocol stack in the Linux kernel to conduct simulations. As such,
more realistic and high-fidelity simulation results are generated. In addition, any real-life application
program can be run up on a simulated NCTUns device during simulation. This capability provides
several unique and important advantages such as: 1) realistic network traffic can be generated by
reallife applications on NCTUns to generate more realistic simulation results. 2) the performance of
any real-life application can be easily evaluated on NCTUns under various simulated network
conditions, and 3) any network application program developed for a NCTUns device can be directly
run up on a real-life Linux device without any modification. Recently, Intelligent Transportation
Systems (ITS) research has gained much attention due to its abundant research and business potential.
NCTUns has supported the simulation of ITS vehicular networks in its 4.0 release (released on July 25,
2007). In the 4.0 release, NCTUns supports
1) basic driver behavior models;
2) basic road network construction; and
3) simulation of road side unit (RSU) and on-board unit (OBU) devices that are equipped with a radio,
which can be an IEEE 802.11(b) infrastructure mode radio, IEEE 802.11(b) ad-hoc mode radio, GPRS
radio, or DVBRCST satellite radio.
As compared with other ITS network simulators such as SUMO [5], NCTUns 4.0 provides users with a
simulation environment in which traffic simulation and network simulation are tightly integrated. With
this unique design, many advanced ITS researches in which a vehicle needs to quickly change its
driving behavior after receiving a message from the network can be studied. Many unique advantages
brought by this design have been presented in detail in [6].
In its 5.0 release (scheduled to be released in July, 2008), NCTUns greatly enhances its supports for
ITS network simulations. Such new functions include :
1) efficient node mobility control for very-large-scale vehicular networks;
2) automatic road network construction from the popular SHAPE-format map file; and, most
importantly,
3) complete simulation of the IEEE 802.11(p)/1609 standards for wireless vehicular networks (WVN).
2. IMPLEMENTATION OF OBU AND RSU ON NCTUNS 5.0
NCTUns 5.0 supports two types of nodes for IEEE 802.11(p)/1609 WVNs. One is “802.11(p) RSU”
and the other is “802.11(p) OBU.” The former is usually deployed at an intersection as a fixed relay
node while the latter is usually installed on a vehicle as an end-user terminal device. Fig. 1 shows a
snapshot of an IEEE 802.11(p)/1609 WVN created using NCTUns 5.0 GUI, where an 802.11(p) RSU
is deployed at the intersection while several 802.11(p) OBUs are deployed on the simulated road
network. Each dotted circle shown in the figure denotes the interference range of each RSU’s or OBU’s
radio, while the colored arrows denote the 802.11(p) MAC-layer DATA frame that the RSU is
transmitting.
These two types of nodes use the same protocol stack configuration. In the following, we present how
NCTUns 5.0 realizes this IEEE 802.11(p)/1609 protocol stack. The simulation architecture used by
NCTUns 5.0 for this new network is shown on the left of Fig. 2, which is explained below.
A. Application Program
NCTUns directly executes a user-level application process to realize the functions of the application
intended to be run on an IEEE 802.11(p)/1609 node. Such an application can transmit or receive 1) IP
packets via the standard socket interface [6] or 2) WAVE short messages via the special WSMP
Application Programming Interfaces (WSMP APIs) provided by the NCTUns simulation engine. The
WSMP APIs are implemented using inter-process communication (IPC) between an application
program and the simulation engine. NCTUns 5.0 does not implement the resource management and
security functions defined by the IEEE 1609.1 and IEEE 1609.2 standards. This decision is made
because these two standards are irrelevant to network performance evaluations.
Simulation architecture of NCTUns 5.0 for IEEE 802.11(p)/1609 WVN
B. WSMP
Unlike the TCP/UDP/IP protocol suite, which has been standardized for years and implemented by the
Linux kernel, WSMP is a new network-layer protocol and has not been supported by Linux. As such,
NCTUns 5.0 implements WSMP in its simulation engine as protocol modules. If in the future Linux
3. implements WSMP as part of the standard socket system call library, any user-level application
program can directly call socket system calls on NCTUns to transmit/receive WAVE Short Messages.
C. MAC-layer and Physical-layer Modules
The MAC-layer and physical-layer functions of the IEEE 802.11(p)/1609 network are implemented by
simulation protocol modules. The WME functionality defined by the IEEE 1609.3 is implemented by
the WME module, while the WAVEmode MAC-layer functions, such as channel switching and
802.11(e)-based prioritized channel accesses, are implemented by the “802.11(p) MAC” module.
Finally, the characteristics of OFDM channels are simulated by the OFDM module.
The architecture supporting tactical MANET simulations in NCTUns
CONCLUSION
NCTUns is a novel network simulator and emulator that directly uses real-life applications and Linux
protocol stack to generate high-fidelity simulation results. In its 4.0 release, many features relevant to
advanced ITS researches have been presented in [6]. In its 5.0 release, NCTUns provides a complete
implementation of the emergent IEEE 802.11(p) and 1609 standards for wireless vehicular networks.
With continuous improvements, NCTUns has become a very valuable tool.
![The NCTUns 5.0 Network Simulator and Emulator
INTRODUCTION
The NCTUns network simulator and emulator [1][2] is a valuable tool for network research, planning,
and education. It is an open-source software running on Linux and provides an easy-to-use integrated
GUI environment for users to efficiently conduct simulations/emulations. Many research institutes,
industry companies, and universities are using it for various purposes. The authors of many journal
papers, conference
papers, Ph.D. dissertations, master theses, etc. have used it to conduct researches. By adopting an
innovative kernel re-entering simulation methodology [4], NCTUns provides many unique and
important advantages over traditional network simulators and emulators. For example, NCTUns
directly uses the real-life TCP/IP protocol stack in the Linux kernel to conduct simulations. As such,
more realistic and high-fidelity simulation results are generated. In addition, any real-life application
program can be run up on a simulated NCTUns device during simulation. This capability provides
several unique and important advantages such as: 1) realistic network traffic can be generated by
reallife applications on NCTUns to generate more realistic simulation results. 2) the performance of
any real-life application can be easily evaluated on NCTUns under various simulated network
conditions, and 3) any network application program developed for a NCTUns device can be directly
run up on a real-life Linux device without any modification. Recently, Intelligent Transportation
Systems (ITS) research has gained much attention due to its abundant research and business potential.
NCTUns has supported the simulation of ITS vehicular networks in its 4.0 release (released on July 25,
2007). In the 4.0 release, NCTUns supports
1) basic driver behavior models;
2) basic road network construction; and
3) simulation of road side unit (RSU) and on-board unit (OBU) devices that are equipped with a radio,
which can be an IEEE 802.11(b) infrastructure mode radio, IEEE 802.11(b) ad-hoc mode radio, GPRS
radio, or DVBRCST satellite radio.
As compared with other ITS network simulators such as SUMO [5], NCTUns 4.0 provides users with a
simulation environment in which traffic simulation and network simulation are tightly integrated. With
this unique design, many advanced ITS researches in which a vehicle needs to quickly change its
driving behavior after receiving a message from the network can be studied. Many unique advantages
brought by this design have been presented in detail in [6].
In its 5.0 release (scheduled to be released in July, 2008), NCTUns greatly enhances its supports for
ITS network simulations. Such new functions include :
1) efficient node mobility control for very-large-scale vehicular networks;
2) automatic road network construction from the popular SHAPE-format map file; and, most
importantly,
3) complete simulation of the IEEE 802.11(p)/1609 standards for wireless vehicular networks (WVN).](https://image.slidesharecdn.com/2796090/85/The-NCTUns-5-0-Network-Simulator-1-320.jpg)
![IMPLEMENTATION OF OBU AND RSU ON NCTUNS 5.0
NCTUns 5.0 supports two types of nodes for IEEE 802.11(p)/1609 WVNs. One is “802.11(p) RSU”
and the other is “802.11(p) OBU.” The former is usually deployed at an intersection as a fixed relay
node while the latter is usually installed on a vehicle as an end-user terminal device. Fig. 1 shows a
snapshot of an IEEE 802.11(p)/1609 WVN created using NCTUns 5.0 GUI, where an 802.11(p) RSU
is deployed at the intersection while several 802.11(p) OBUs are deployed on the simulated road
network. Each dotted circle shown in the figure denotes the interference range of each RSU’s or OBU’s
radio, while the colored arrows denote the 802.11(p) MAC-layer DATA frame that the RSU is
transmitting.
These two types of nodes use the same protocol stack configuration. In the following, we present how
NCTUns 5.0 realizes this IEEE 802.11(p)/1609 protocol stack. The simulation architecture used by
NCTUns 5.0 for this new network is shown on the left of Fig. 2, which is explained below.
A. Application Program
NCTUns directly executes a user-level application process to realize the functions of the application
intended to be run on an IEEE 802.11(p)/1609 node. Such an application can transmit or receive 1) IP
packets via the standard socket interface [6] or 2) WAVE short messages via the special WSMP
Application Programming Interfaces (WSMP APIs) provided by the NCTUns simulation engine. The
WSMP APIs are implemented using inter-process communication (IPC) between an application
program and the simulation engine. NCTUns 5.0 does not implement the resource management and
security functions defined by the IEEE 1609.1 and IEEE 1609.2 standards. This decision is made
because these two standards are irrelevant to network performance evaluations.
Simulation architecture of NCTUns 5.0 for IEEE 802.11(p)/1609 WVN
B. WSMP
Unlike the TCP/UDP/IP protocol suite, which has been standardized for years and implemented by the
Linux kernel, WSMP is a new network-layer protocol and has not been supported by Linux. As such,
NCTUns 5.0 implements WSMP in its simulation engine as protocol modules. If in the future Linux](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)