The document discusses wireless local area networks (WLANs) and the IEEE 802.11 standards. It describes some of the challenges of wireless transmissions and provides an overview of the IEEE 802.11 standards including 802.11, 802.11a, 802.11b, 802.11e, and 802.11g. It also summarizes the IEEE 802.11 network architecture including the physical layer, data link layer, and different network topologies like IBSS, BSS, and ESS.
IEEE 802.11 defines two medium access methods - Distributed Coordination Function (DCF) where all stations share the medium equally using carrier sense and random backoffs, and Point Coordination Function (PCF) where a central point coordinator polls stations for transmission. DCF is more widely used. 802.11e introduced Enhanced Distributed Channel Access (EDCA) to provide quality of service by prioritizing traffic categories, and HCF Controlled Channel Access (HCCA) which extends PCF with scheduled polling. Power saving modes allow stations to sleep and wake periodically to receive buffered frames from the access point.
The document discusses the protocol layers and architecture of IEEE 802.11 wireless LAN standards. It describes the functions of the physical, medium access control (MAC), and logical link control (LLC) layers. The MAC frame format and access control methods using interframe spaces are also summarized. Additionally, it outlines services provided within IEEE 802.11 wireless distributions systems including distribution, integration, and mobility-related services.
Hamdard University Bangladesh provides an introduction to IEEE 802.11 wireless LAN specifications. It defines two types of MAC sublayer services and describes the distribution coordination function which allows stations to transmit if the medium is idle or wait until the current transmission is complete if busy. It also discusses the point coordination function implemented in infrastructure networks which uses repetition intervals for contention-free transmissions.
The document provides information about the IEEE 802.11 WLAN standard and its various layers:
- The PHY layer includes the physical layer convergence protocol and physical medium dependent sublayers. The PHY layer supports FHSS, DSSS and infrared spread spectrum techniques.
- The MAC layer supports distributed coordination function based on CSMA/CA and RTS/CTS, as well as point coordination function controlled by an access point. It defines frame formats and medium access mechanisms.
The local area technologies as 1-WLAN(Wireless Local Area Network) with moderate bandwidth. And WiMax
2.The large area technologies as GSM, GPRSor UMTS, LTEwhich have much higher bandwidth.
A wireless local area network (WLAN) uses radio waves to wirelessly connect devices within a local area like a home or office, often including an access point to connect to the internet. WLANs use specialized protocols at the physical and data link layers and integrate into existing networks through access points. Common WLAN standards include IEEE 802.11b, 802.11a, and 802.11g which provide speeds up to 11Mbps, 54Mbps, and 54Mbps respectively in the 2.4GHz and 5GHz bands. Real-time services like voice can be transported over WLANs using protocols like PCF but may require echo cancellation to meet latency requirements.
The document discusses wireless local area networks (WLANs) and the IEEE 802.11 standard. It provides an overview of wired and wireless LANs, the development and specifications of IEEE 802.11, and differences between wireless and wired networks that 802.11 addresses like power management, security, and bandwidth. It also covers wireless LAN topologies, media access control, security issues, and physical layer standards defined in original 802.11 like frequency hopping spread spectrum and direct sequence spread spectrum.
VLAN Virtual Area Network ,Switch,Ethernet ,VIkram SnehiMR. VIKRAM SNEHI
A VLAN allows computers on different physical LAN segments to communicate as if they were on the same LAN. VLANs logically segment LANs into different broadcast domains by using frame tagging to identify which VLAN a frame belongs to. There are two main types of VLAN configurations - static, where ports are manually assigned to VLANs, and dynamic, where assignments are made via network management software based on device MAC addresses.
IEEE 802.11 defines two medium access methods - Distributed Coordination Function (DCF) where all stations share the medium equally using carrier sense and random backoffs, and Point Coordination Function (PCF) where a central point coordinator polls stations for transmission. DCF is more widely used. 802.11e introduced Enhanced Distributed Channel Access (EDCA) to provide quality of service by prioritizing traffic categories, and HCF Controlled Channel Access (HCCA) which extends PCF with scheduled polling. Power saving modes allow stations to sleep and wake periodically to receive buffered frames from the access point.
The document discusses the protocol layers and architecture of IEEE 802.11 wireless LAN standards. It describes the functions of the physical, medium access control (MAC), and logical link control (LLC) layers. The MAC frame format and access control methods using interframe spaces are also summarized. Additionally, it outlines services provided within IEEE 802.11 wireless distributions systems including distribution, integration, and mobility-related services.
Hamdard University Bangladesh provides an introduction to IEEE 802.11 wireless LAN specifications. It defines two types of MAC sublayer services and describes the distribution coordination function which allows stations to transmit if the medium is idle or wait until the current transmission is complete if busy. It also discusses the point coordination function implemented in infrastructure networks which uses repetition intervals for contention-free transmissions.
The document provides information about the IEEE 802.11 WLAN standard and its various layers:
- The PHY layer includes the physical layer convergence protocol and physical medium dependent sublayers. The PHY layer supports FHSS, DSSS and infrared spread spectrum techniques.
- The MAC layer supports distributed coordination function based on CSMA/CA and RTS/CTS, as well as point coordination function controlled by an access point. It defines frame formats and medium access mechanisms.
The local area technologies as 1-WLAN(Wireless Local Area Network) with moderate bandwidth. And WiMax
2.The large area technologies as GSM, GPRSor UMTS, LTEwhich have much higher bandwidth.
A wireless local area network (WLAN) uses radio waves to wirelessly connect devices within a local area like a home or office, often including an access point to connect to the internet. WLANs use specialized protocols at the physical and data link layers and integrate into existing networks through access points. Common WLAN standards include IEEE 802.11b, 802.11a, and 802.11g which provide speeds up to 11Mbps, 54Mbps, and 54Mbps respectively in the 2.4GHz and 5GHz bands. Real-time services like voice can be transported over WLANs using protocols like PCF but may require echo cancellation to meet latency requirements.
The document discusses wireless local area networks (WLANs) and the IEEE 802.11 standard. It provides an overview of wired and wireless LANs, the development and specifications of IEEE 802.11, and differences between wireless and wired networks that 802.11 addresses like power management, security, and bandwidth. It also covers wireless LAN topologies, media access control, security issues, and physical layer standards defined in original 802.11 like frequency hopping spread spectrum and direct sequence spread spectrum.
VLAN Virtual Area Network ,Switch,Ethernet ,VIkram SnehiMR. VIKRAM SNEHI
A VLAN allows computers on different physical LAN segments to communicate as if they were on the same LAN. VLANs logically segment LANs into different broadcast domains by using frame tagging to identify which VLAN a frame belongs to. There are two main types of VLAN configurations - static, where ports are manually assigned to VLANs, and dynamic, where assignments are made via network management software based on device MAC addresses.
The document provides an overview of IEEE 802.11 standards for wireless local area networks. It discusses the creation of 802.11 by IEEE, the physical layer, frame formats, and various 802.11 protocols including 802.11b, 802.11a, 802.11g, 802.11n, and 802.11ac. It also describes the media access control including CSMA/CA and security features like authentication and WEP encryption.
802.11 wireless LANs (WLANs) allow wireless hosts to connect to wired networks via radio connections to access points. Access points connect wireless users to a firm's main wired LAN and provide internet access. Wireless speeds range from 10-300 Mbps depending on the 802.11 standard used, with ranges of 30-100 meters between devices. WLANs use unlicensed radio frequency bands at 2.4GHz or 5GHz to operate. Security standards like WEP, WPA, and WPA2 provide encryption and authentication for wireless connections.
This document discusses virtual local area networks (VLANs). It defines VLANs as logically segmenting switched networks based on functions, project teams, or applications, regardless of physical location or network connections. VLANs divide stations into logical groups through software instead of physical segments, allowing easy movement of stations between groups without changing physical configurations. Common VLAN types include port-based, MAC address-based, and protocol-based. Benefits of VLANs include logical organization of networks, easy moves and additions of workstations, flexible configuration changes, traffic control, and improved security.
The document provides an overview of the IEEE 802.11 MAC protocol through a presentation. It discusses topics such as IEEE 802.11 layers, channels, infrastructure networks, ad hoc networks, joining a network, synchronization, communication approaches, MAC functionality including PCF and DCF, encryption, fragmentation, management functions, and MAC frame formats. The presentation was given on May 9th, 2001 by Mahdi Ahmed Jama to provide an introduction to the IEEE 802.11a MAC protocol.
The document discusses key aspects of IEEE 802.11 wireless LAN standards. It describes the 802.11b, 802.11a, 802.11g, and 802.11n standards which operate in the 2.4-5GHz range and have data rates up to 11Mbps, 54Mbps, 54Mbps, and 200Mbps respectively. It explains the basic service set architecture with wireless hosts communicating through an access point. It also covers CSMA/CA for medium access, addressing in 802.11 frames, and mobility and power management in 802.11 networks.
The document summarizes mobile ad hoc networks (MANETs) and some of the key challenges in designing protocols for them. It covers medium access control protocols, routing protocols, and some examples. Specifically, it discusses MACA for medium access, reactive routing protocols like DSR, proactive protocols like DSDV, and hybrid protocols like ZRP. It also outlines some of the tradeoffs between proactive and reactive routing approaches for mobile networks.
This document summarizes a tutorial on mobile ad hoc networks. It first discusses the characteristics and challenges of mobile ad hoc networks, including frequent topology changes and limited bandwidth. It then covers various aspects of designing protocols for mobile ad hoc networks, including medium access control, routing, and transport. For medium access control, it describes MACA and IEEE 802.11. For routing, it discusses reactive, proactive, and hybrid routing protocols and the tradeoffs between them. The document provides an overview of key considerations and approaches for building mobile ad hoc network protocols.
VLANs logically segment LANs into broadcast domains by using switches to assign ports and their attached devices to VLAN groups based on their MAC address, IP subnet, or switch port. This allows devices that are physically located on different floors or buildings to belong to the same logical LAN segment while preventing Layer 2 broadcasts from crossing VLAN boundaries. VLAN trunk links between switches allow multiple VLANs to be transmitted over the same physical link.
This document discusses various wireless networks including WiMAX, cellular networks, and satellite networks. It describes WiMAX services and standards, the evolution of cellular networks from 1G to 4G, and key aspects of satellite network operations including orbit types, footprints, and frequency bands. Specifically, it outlines the characteristics of GEO, MEO, and LEO satellite orbits and provides examples for each type. The document provides a technical overview of the technologies, standards, and applications of several major wireless networking approaches.
WSN protocol 802.15.4 together with cc2420 seminars Salah Amean
WSN protocol 802.15.4 together with cc2420 seminars . It is based on the standand of ieee802.15.4 and data sheet of the radio transceiver cc2420.
Note that some slides are borrowed.
This document provides an overview of local area networks (LANs) and virtual LANs (VLANs). It defines LAN as a network covering a small area like a home, office or campus to connect computers in close proximity. The document discusses common LAN topologies like bus, ring and star. It then introduces VLAN as a way to logically segment devices within a LAN even if they share the same infrastructure. The document explains how VLANs work using tags and trunking between switches. It outlines benefits of VLANs like improved security, flexibility and traffic management compared to traditional LANs.
This document discusses switching and VLANs. It provides information on:
1. How switches learn host locations by caching source MAC addresses in the MAC address table and flooding unknown frames.
2. How switches filter frames by only forwarding frames to ports associated with the destination MAC address in the table.
3. Problems that can occur in redundant network topologies like broadcast storms from repeated flooding, multiple copies of frames, and unstable MAC address tables.
4. How VLANs and trunking can segment networks into multiple broadcast domains to address these issues while maintaining connectivity across switches.
The document summarizes a lecture on wireless networks. It outlines the key requirements for wireless LANs including throughput, number of supported nodes, quality of service, energy saving, and roaming support. It also describes various wireless LAN technologies like infrared, UHF narrowband, and spread spectrum. Finally, it provides an overview of the IEEE 802.11 wireless LAN standard including the physical layers, bands, and data rates supported by different versions of the standard.
Wireless Communications and a Priority Access Protocol for Multiple Mobile Te...MNIT Jaipur
IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION, VOL. 14, NO. 1, FEBRUARY 1998
PPT ON Wireless Communications and a Priority
Access Protocol for Multiple Mobile
Terminals in Factory Automation
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.
The document discusses the components and architectures of wireless networks. It describes basic service sets (BSS) which can be either ad-hoc or infrastructure networks, and extended service sets (ESS) which connect multiple BSS through a distribution system. It also outlines the 802.11 protocol stack and frame formats, including the frame control field and address fields.
This document discusses drive testing for mobile networks. It describes the requirements and process for conducting drive tests, including the necessary equipment. It outlines different types of drive tests like routine, problem-specific, and coverage analysis tests. It also discusses the various metrics and measurements that are analyzed from drive test data like signal levels, call quality, handovers, and throughput. Finally, it mentions Neptune and Probe software tools that can be used for real-time and post-analysis of drive test results.
This document outlines the evolution of Ethernet networking standards from the original Ethernet developed at Xerox PARC to modern Gigabit and 10-Gigabit Ethernet standards. It discusses the IEEE 802.3 working group and standards for various Ethernet technologies including 10BASE-T, 100BASE-TX, 1000BASE-T, and 10GbE. Encoding methods like 4D-PAM5 that have allowed Ethernet speeds to increase over twisted pair cabling are also covered at a high level.
Routing Protocols and Concepts: Ch5 - Routing Information Protocol (RIP v1)Abdelkhalik Mosa
Routing Information Protocol Version 1 (RIPv1) history and characteristics.
RIP v1 message format.
RIP Request / Response Process.
IP Address Classes and Classful Routing.
RIP v1 Configuration, Router RIP command, Network command, Show IP Route, debug IP RIP and Show ip protocols.
Passive Interfaces, Boundary Routers and Automatic Summarization.
Advantages and Disadvantages of automatic summarization.
Processing RIP Updates, Default Route and RIPv1
The document discusses wireless local area networks (WLANs) and personal area networks (PANs). It describes the characteristics and fundamentals of WLANs, including their advantages like flexibility and lower costs, and disadvantages such as lower bandwidth and security issues. It provides details on common wireless standards like IEEE 802.11, Bluetooth, and HomeRF. It also compares infrastructure-based and ad-hoc network topologies and summarizes key aspects of the IEEE 802.11 standard including services, physical layers, and frame formats.
Wireless LAN allows for mobility by providing a local area network without wires. It functions as an extension of a wired LAN within a building or campus. Key advantages include mobility, low implementation costs, and easier network expansion. Wireless LAN standards like 802.11 have evolved to support higher bandwidths and seamless vertical and horizontal roaming between networks. Wireless LANs operate in both infrastructure and ad-hoc modes and use techniques like CSMA/CA, fragmentation, and power saving to manage access and energy efficiency in a wireless environment.
The document provides an overview of IEEE 802.11 standards for wireless local area networks. It discusses the creation of 802.11 by IEEE, the physical layer, frame formats, and various 802.11 protocols including 802.11b, 802.11a, 802.11g, 802.11n, and 802.11ac. It also describes the media access control including CSMA/CA and security features like authentication and WEP encryption.
802.11 wireless LANs (WLANs) allow wireless hosts to connect to wired networks via radio connections to access points. Access points connect wireless users to a firm's main wired LAN and provide internet access. Wireless speeds range from 10-300 Mbps depending on the 802.11 standard used, with ranges of 30-100 meters between devices. WLANs use unlicensed radio frequency bands at 2.4GHz or 5GHz to operate. Security standards like WEP, WPA, and WPA2 provide encryption and authentication for wireless connections.
This document discusses virtual local area networks (VLANs). It defines VLANs as logically segmenting switched networks based on functions, project teams, or applications, regardless of physical location or network connections. VLANs divide stations into logical groups through software instead of physical segments, allowing easy movement of stations between groups without changing physical configurations. Common VLAN types include port-based, MAC address-based, and protocol-based. Benefits of VLANs include logical organization of networks, easy moves and additions of workstations, flexible configuration changes, traffic control, and improved security.
The document provides an overview of the IEEE 802.11 MAC protocol through a presentation. It discusses topics such as IEEE 802.11 layers, channels, infrastructure networks, ad hoc networks, joining a network, synchronization, communication approaches, MAC functionality including PCF and DCF, encryption, fragmentation, management functions, and MAC frame formats. The presentation was given on May 9th, 2001 by Mahdi Ahmed Jama to provide an introduction to the IEEE 802.11a MAC protocol.
The document discusses key aspects of IEEE 802.11 wireless LAN standards. It describes the 802.11b, 802.11a, 802.11g, and 802.11n standards which operate in the 2.4-5GHz range and have data rates up to 11Mbps, 54Mbps, 54Mbps, and 200Mbps respectively. It explains the basic service set architecture with wireless hosts communicating through an access point. It also covers CSMA/CA for medium access, addressing in 802.11 frames, and mobility and power management in 802.11 networks.
The document summarizes mobile ad hoc networks (MANETs) and some of the key challenges in designing protocols for them. It covers medium access control protocols, routing protocols, and some examples. Specifically, it discusses MACA for medium access, reactive routing protocols like DSR, proactive protocols like DSDV, and hybrid protocols like ZRP. It also outlines some of the tradeoffs between proactive and reactive routing approaches for mobile networks.
This document summarizes a tutorial on mobile ad hoc networks. It first discusses the characteristics and challenges of mobile ad hoc networks, including frequent topology changes and limited bandwidth. It then covers various aspects of designing protocols for mobile ad hoc networks, including medium access control, routing, and transport. For medium access control, it describes MACA and IEEE 802.11. For routing, it discusses reactive, proactive, and hybrid routing protocols and the tradeoffs between them. The document provides an overview of key considerations and approaches for building mobile ad hoc network protocols.
VLANs logically segment LANs into broadcast domains by using switches to assign ports and their attached devices to VLAN groups based on their MAC address, IP subnet, or switch port. This allows devices that are physically located on different floors or buildings to belong to the same logical LAN segment while preventing Layer 2 broadcasts from crossing VLAN boundaries. VLAN trunk links between switches allow multiple VLANs to be transmitted over the same physical link.
This document discusses various wireless networks including WiMAX, cellular networks, and satellite networks. It describes WiMAX services and standards, the evolution of cellular networks from 1G to 4G, and key aspects of satellite network operations including orbit types, footprints, and frequency bands. Specifically, it outlines the characteristics of GEO, MEO, and LEO satellite orbits and provides examples for each type. The document provides a technical overview of the technologies, standards, and applications of several major wireless networking approaches.
WSN protocol 802.15.4 together with cc2420 seminars Salah Amean
WSN protocol 802.15.4 together with cc2420 seminars . It is based on the standand of ieee802.15.4 and data sheet of the radio transceiver cc2420.
Note that some slides are borrowed.
This document provides an overview of local area networks (LANs) and virtual LANs (VLANs). It defines LAN as a network covering a small area like a home, office or campus to connect computers in close proximity. The document discusses common LAN topologies like bus, ring and star. It then introduces VLAN as a way to logically segment devices within a LAN even if they share the same infrastructure. The document explains how VLANs work using tags and trunking between switches. It outlines benefits of VLANs like improved security, flexibility and traffic management compared to traditional LANs.
This document discusses switching and VLANs. It provides information on:
1. How switches learn host locations by caching source MAC addresses in the MAC address table and flooding unknown frames.
2. How switches filter frames by only forwarding frames to ports associated with the destination MAC address in the table.
3. Problems that can occur in redundant network topologies like broadcast storms from repeated flooding, multiple copies of frames, and unstable MAC address tables.
4. How VLANs and trunking can segment networks into multiple broadcast domains to address these issues while maintaining connectivity across switches.
The document summarizes a lecture on wireless networks. It outlines the key requirements for wireless LANs including throughput, number of supported nodes, quality of service, energy saving, and roaming support. It also describes various wireless LAN technologies like infrared, UHF narrowband, and spread spectrum. Finally, it provides an overview of the IEEE 802.11 wireless LAN standard including the physical layers, bands, and data rates supported by different versions of the standard.
Wireless Communications and a Priority Access Protocol for Multiple Mobile Te...MNIT Jaipur
IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION, VOL. 14, NO. 1, FEBRUARY 1998
PPT ON Wireless Communications and a Priority
Access Protocol for Multiple Mobile
Terminals in Factory Automation
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.
The document discusses the components and architectures of wireless networks. It describes basic service sets (BSS) which can be either ad-hoc or infrastructure networks, and extended service sets (ESS) which connect multiple BSS through a distribution system. It also outlines the 802.11 protocol stack and frame formats, including the frame control field and address fields.
This document discusses drive testing for mobile networks. It describes the requirements and process for conducting drive tests, including the necessary equipment. It outlines different types of drive tests like routine, problem-specific, and coverage analysis tests. It also discusses the various metrics and measurements that are analyzed from drive test data like signal levels, call quality, handovers, and throughput. Finally, it mentions Neptune and Probe software tools that can be used for real-time and post-analysis of drive test results.
This document outlines the evolution of Ethernet networking standards from the original Ethernet developed at Xerox PARC to modern Gigabit and 10-Gigabit Ethernet standards. It discusses the IEEE 802.3 working group and standards for various Ethernet technologies including 10BASE-T, 100BASE-TX, 1000BASE-T, and 10GbE. Encoding methods like 4D-PAM5 that have allowed Ethernet speeds to increase over twisted pair cabling are also covered at a high level.
Routing Protocols and Concepts: Ch5 - Routing Information Protocol (RIP v1)Abdelkhalik Mosa
Routing Information Protocol Version 1 (RIPv1) history and characteristics.
RIP v1 message format.
RIP Request / Response Process.
IP Address Classes and Classful Routing.
RIP v1 Configuration, Router RIP command, Network command, Show IP Route, debug IP RIP and Show ip protocols.
Passive Interfaces, Boundary Routers and Automatic Summarization.
Advantages and Disadvantages of automatic summarization.
Processing RIP Updates, Default Route and RIPv1
The document discusses wireless local area networks (WLANs) and personal area networks (PANs). It describes the characteristics and fundamentals of WLANs, including their advantages like flexibility and lower costs, and disadvantages such as lower bandwidth and security issues. It provides details on common wireless standards like IEEE 802.11, Bluetooth, and HomeRF. It also compares infrastructure-based and ad-hoc network topologies and summarizes key aspects of the IEEE 802.11 standard including services, physical layers, and frame formats.
Wireless LAN allows for mobility by providing a local area network without wires. It functions as an extension of a wired LAN within a building or campus. Key advantages include mobility, low implementation costs, and easier network expansion. Wireless LAN standards like 802.11 have evolved to support higher bandwidths and seamless vertical and horizontal roaming between networks. Wireless LANs operate in both infrastructure and ad-hoc modes and use techniques like CSMA/CA, fragmentation, and power saving to manage access and energy efficiency in a wireless environment.
The document provides an overview of WiFi networks and various IEEE 802.11 standards. It discusses basic WiFi concepts and deployment issues. It then summarizes several key WiFi versions including 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, and 802.11ad and how each standard improved data rates and functionality compared to previous versions through techniques like channel bonding and MIMO.
The document provides information about wireless networks and standards including IEEE 802.11 (Wi-Fi), Bluetooth, and WiMAX. It discusses the goals and architecture of wireless LANs and PANs, as well as standards like IEEE 802.11, Bluetooth, and their protocols. Key topics covered include the IEEE 802.11 standard including physical layer specifications and MAC architecture, Bluetooth architecture and piconet/scatternet topologies, and protocols in the Bluetooth and IEEE 802.11 stacks.
- Wireless LANs use either wired or wireless infrastructure to connect computing devices within a local area. Wireless LANs provide flexibility, portability, mobility and ease of installation compared to wired LANs.
- The IEEE 802.11 standard defines the physical and data link layers for wireless LANs. It addresses issues like power management, security, and bandwidth that are important for wireless networks.
- The MAC layer uses either a contention-based distributed coordination function (DCF) or contention-free point coordination function (PCF). DCF uses CSMA/CA for channel access while PCF uses polling for contention-free access.
This document provides an overview of the IEEE 802.11 WiFi standard in 3 parts. Part 1 discusses advantages and disadvantages of WiFi networks. Part 2 describes the physical layer specifications including spectrum, modulation techniques, and OFDM. Part 3 covers the media access control layer and protocols like CSMA/CA, RTS/CTS, and acknowledgments that provide reliability. The document is intended for teaching purposes and draws from various academic sources.
The document discusses wireless communication technologies and standards, including wireless local area networks (WLANs). It provides information on:
1) The IEEE 802.11 standard which is the dominant standard for WLANs and supports two modes - infrastructure mode where devices connect to an access point, and ad-hoc mode for direct peer-to-peer connections.
2) The process for a device to join a wireless network in infrastructure mode which involves discovering available networks, selecting a network, performing authentication, and associating with the access point.
3) The media access control (MAC) layer which coordinates access to the shared wireless medium using carrier sense multiple access with collision avoidance (CSMA/CA) and
The document provides an overview of wireless networks and wireless communication technologies. It discusses the key elements of a wireless network including wireless hosts, base stations, wireless links, infrastructure and ad hoc modes. It also covers wireless link characteristics such as signal attenuation, interference and multipath propagation. Finally, it introduces common wireless network standards and protocols including IEEE 802.11 wireless LANs, wireless network characteristics such as the hidden terminal problem, and wireless multiple access protocols.
This document provides an overview of wireless local area networks (WLANs) and various IEEE 802.11 standards. It describes the characteristics and design goals of WLANs. It also compares infrastructure vs. ad-hoc network architectures and examines the physical layer, MAC layer, and management functions of 802.11. Specific standards like 802.11a, 802.11b, and future developments are outlined. The document provides details on aspects like channel selection, data rates, transmission ranges, and security considerations for different 802.11 technologies.
IEEE 802.11 is a set of media access control (MAC) and physical layer (PHY) specifications for implementing wireless local area network (WLAN) computer communication in the 2.4, 3.6, 5, and 60 GHz frequency bands. The goal of 802.11 is to provide simple, robust, and affordable wireless connectivity along with time-bound and asynchronous services. It uses either spread spectrum or infrared signaling techniques. The standard defines the MAC sublayer and three physical layer types: infrared, frequency-hopping spread spectrum (FHSS), and direct-sequence spread spectrum (DSSS). It supports infrastructure-based and ad-hoc network configurations.
The document discusses computer networks and media access control. It covers topics like Ethernet, wireless LANs, Bluetooth, Wi-Fi, switching, bridging, IP, and more. The key points are:
1. It provides an overview of the topics to be discussed, including media access control, Ethernet standards, wireless technologies, and internetworking basics.
2. It summarizes the evolution of Ethernet and discusses its physical properties, frame format, addressing, and transmitter algorithm using CSMA/CD.
3. It describes wireless LAN standards like Bluetooth and Wi-Fi, addressing problems in wireless networks, and discussing concepts like spread spectrum, CSMA/CA, and network architectures.
A wireless LAN or WLAN uses radio waves to connect devices in a local area network without wires. It uses access points to bridge wireless traffic to a wired backbone network. Wireless LANs use standards like 802.11 and connect devices in a basic service set through an access point, or extend coverage through multiple access points in an extended service set. They operate at the data link layer using CSMA/CA for media access and can provide optional security measures for authentication and privacy.
This document discusses wireless local area networks (WLANs). It describes how WLANs use wireless transmission to connect devices within a local area, avoiding the need for wired networking. It covers different types of WLAN configurations including single-cell, multi-cell, infrastructure and ad-hoc networks. It also discusses wireless networking technologies like infrared, spread spectrum and microwave transmission and compares their strengths and weaknesses. Finally, it examines the IEEE 802.11 wireless networking standard and its media access control protocols.
This chapter discusses wireless LANs, including their growth in popularity as issues like high prices and licensing requirements have been addressed. Wireless LANs can be used to extend a wired LAN by replacing cabling, though replacing the wired LAN entirely has not occurred. Wireless LANs are used in environments like open areas, historical buildings, and small offices where wired LANs are not economical. Key technologies discussed include infrared and spread spectrum LANs. The IEEE 802.11 standard defines the basic service set and extended service set for wireless LAN configuration and services.
This document discusses wireless local area networks (WLANs). It describes how WLANs use wireless transmission to connect devices within a local area, avoiding the need for wired networking. It covers different types of WLAN configurations including single-cell, multi-cell, infrastructure and ad-hoc networks. It also discusses wireless networking technologies like infrared, spread spectrum and microwave transmission and compares their strengths and weaknesses. Finally, it examines the IEEE 802.11 wireless networking standard and its use of distributed coordination function (DCF) and point coordination function (PCF) for medium access control.
This document provides an overview of wireless LAN and Bluetooth technologies. It describes IEEE 802.11 standards for wireless LAN including the basic service set, extended service set, infrastructure and ad-hoc modes. It covers the physical layers, MAC protocols and services of 802.11. It also summarizes ATM and its extension to wireless networks, issues in the transition, proposed W-ATM architectures, advantages and disadvantages. Finally it defines Bluetooth technology, the protocol stack and unlicensed frequency band used.
These ppt are the part 2 of mobile computing concepts. These ppt defines the following things
Wireless Networking
Wireless LAN Overview: IEEE 802.11
Wireless applications
Data Broadcasting
Bluetooth
TCP over wireless
Mobile IP
WAP: Architecture, protocol stack, application
environment, applications.
Wireless LANs allow for wireless transmission of data within a local area network (LAN). The document discusses:
1. Wireless LANs were initially more expensive and had lower data rates than wired LANs, but these issues have been addressed and wireless LAN popularity has grown.
2. Wireless LANs are commonly used to extend existing wired LANs by avoiding cable installation, and to provide connectivity in areas not suited for wired LANs like large open spaces.
3. The IEEE 802.11 standard defines the media access control (MAC) and physical layers for wireless LANs. It uses carrier sense multiple access with collision avoidance (CSMA/CA) for distributed
This document discusses high-speed local area networks (LANs) including Fast and Gigabit Ethernet. It describes how LAN usage has evolved from basic connectivity to supporting large file transfers and graphics-intensive applications. It also outlines some key applications that require high-speed LANs like centralized server farms and power workgroups. The document then reviews different LAN technologies like Ethernet, token ring, and wireless and how carrier sense multiple access with collision detection (CSMA/CD) works. It concludes by discussing Fast Ethernet specifications and how Gigabit Ethernet differs.
This document provides a project synopsis for developing a highly efficient web crawler. The objective is to browse the World Wide Web in an automated manner. A web crawler is a computer program that methodically explores websites by starting with a list of seed URLs and identifying links to add to a crawl frontier. As the crawler visits URLs, it finds and adds all hyperlinks to the frontier to visit recursively. The synopsis provides an introduction to web crawlers and their uses, as well as the machine specifications required.
This project aims to develop an efficient web crawler to browse the World Wide Web in an automated manner. The web crawler will be created by students Atul Singh and Mayur Garg under the guidance of their mentor Mrs. Deepika. A web crawler systematically visits websites to create copies of pages for search engines to index, starting with an initial list of URLs. This specific crawler will be developed to have a high performance using a computer with 640MB memory, 100Mbps internet connection, and running Windows XP/Vista with Java SDK 1.6 and a database client.
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This document discusses high-speed local area networks (LANs). It describes how LAN traffic and needs have increased with more powerful PCs and graphics-intensive applications. Applications that require high-speed LANs include centralized server farms and power workgroups that transfer large data files. Common high-speed LAN technologies discussed include Fast and Gigabit Ethernet, Fibre Channel, and high-speed wireless LANs.
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Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-und-domino-lizenzkostenreduzierung-in-der-welt-von-dlau/
DLAU und die Lizenzen nach dem CCB- und CCX-Modell sind für viele in der HCL-Community seit letztem Jahr ein heißes Thema. Als Notes- oder Domino-Kunde haben Sie vielleicht mit unerwartet hohen Benutzerzahlen und Lizenzgebühren zu kämpfen. Sie fragen sich vielleicht, wie diese neue Art der Lizenzierung funktioniert und welchen Nutzen sie Ihnen bringt. Vor allem wollen Sie sicherlich Ihr Budget einhalten und Kosten sparen, wo immer möglich. Das verstehen wir und wir möchten Ihnen dabei helfen!
Wir erklären Ihnen, wie Sie häufige Konfigurationsprobleme lösen können, die dazu führen können, dass mehr Benutzer gezählt werden als nötig, und wie Sie überflüssige oder ungenutzte Konten identifizieren und entfernen können, um Geld zu sparen. Es gibt auch einige Ansätze, die zu unnötigen Ausgaben führen können, z. B. wenn ein Personendokument anstelle eines Mail-Ins für geteilte Mailboxen verwendet wird. Wir zeigen Ihnen solche Fälle und deren Lösungen. Und natürlich erklären wir Ihnen das neue Lizenzmodell.
Nehmen Sie an diesem Webinar teil, bei dem HCL-Ambassador Marc Thomas und Gastredner Franz Walder Ihnen diese neue Welt näherbringen. Es vermittelt Ihnen die Tools und das Know-how, um den Überblick zu bewahren. Sie werden in der Lage sein, Ihre Kosten durch eine optimierte Domino-Konfiguration zu reduzieren und auch in Zukunft gering zu halten.
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- Wie funktionieren CCB- und CCX-Lizenzen wirklich?
- Verstehen des DLAU-Tools und wie man es am besten nutzt
- Tipps für häufige Problembereiche, wie z. B. Team-Postfächer, Funktions-/Testbenutzer usw.
- Praxisbeispiele und Best Practices zum sofortigen Umsetzen
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What will you get from this session?
1. Insights into integrating generative AI.
2. Understanding how this integration enhances test automation within the UiPath platform
3. Practical demonstrations
4. Exploration of real-world use cases illustrating the benefits of AI-driven test automation for UiPath
Topics covered:
What is generative AI
Test Automation with generative AI and Open AI.
UiPath integration with generative AI
Speaker:
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Wireless presentation-1
1. Wireless LANs
• Rat‟s nest of wires
• Variety of power cords and adapters
• Cables for modems, printers, scanner,
mouse and keyboards
• NEED OF CONNECTING COMPUTERS
2. Challenges
• Radio and Infrared transmissions susceptible to
noise and interference
– Unreliable transmission
• Strength varies in time and space
– Fading
• Finite Radio Spectrum
– Shared with other systems
• Radio spectrum regulated by different bodies
3. Wireless LANs
• IEEE 802.11 Standards
• Non IEEE Standards like
– Bluetooth, HIPERLAN, HomeRF
4. What is IEEE 802.11?
• IEEE:
– Institute of Electrical and Electronics Engineers
• 802.11:
– Family of standards set forth by the IEEE to
define the specifications for wireless LANs
– Defines:
• Medium Access Control (MAC)
• Physical Layer (PHY) Specifications
6. What is IEEE 802.11?
• Local, high-speed wireless connectivity for
fixed, portable and moving stations
– stations can be moving at pedestrian and
vehicular speeds
• Standard promises interoperability
– vendors products on the same physical layer
should interoperate
• Targetted for use in
– inside buildings, outdoor areas, anywhere!
7. IEEE 802.11
• Uses Direct Sequence spread spectrum
(DSSS) technology
– Frequency-Hopping spread spectrum (FHSS)
can only be used for 1 or 2Mbps in US due to
FCC regulations
• Operates in unlicensed 2.4 GHz ISM band
– ISM: Industrial, Scientific and Medical
– ISM regulatory range:
• 2.4 GHz to 2.4835 GHz for North America
8. IEEE 802.11
• Supported Speeds and Distances
– 1, 2, 5.5, 11 Mbps at distances of 150-2000 feet
without special antenna
– Greater distances can be achieved by using
special antennas
– Distance (or signal strength) greatly depends on
obstructions such as buildings and other objects
– Maximum speed obtained depends on signal
strength
9. IEEE 802.11b
• „b‟ in IEEE 802.11b
– September 1999, 802.11b “High Rate”
amendment was ratified by the IEEE
– 802.11b amendment to 802.11 only affects the
physical layer, basic architecture is the same
• Added two higher speeds
– 5.5 and 11 Mbps
• More robust connectivity
• 802.11b is the current „favorite‟ in 802.11
– also known as Wi-Fi (Wireless Fidelity)
10. IEEE 802.11a
• “Fast Ethernet” standard of wireless LANs
• Speeds of up to 54 Mbps
• 5 GHz (U-NII band) instead of 2.4 GHz
– Unlicensed National Information Infrastructure
• OFDM instead of DSSS for encoding
– Orthogonal Frequency Division Multiplexing
11. IEEE 802.11a
• Advantages
– higher speed
– less RF interference than 2.4 GHz
• 2.4 GHz used by Bluetooth, cordless/cellular phones,
etc.
– some interoperability, vendors currently have
“dual-standard” 802.11a/b equipment
• Disadvantages
– shorter range, need to increase AP density or
power 4X to compensate
12. IEEE 802.11g
• Another high-speed standard
• Viewed as a „step‟ towards 802.11a
• Speeds of up to 54 Mbps
– may be more like 20+ Mbps
• Still works at 2.4 GHz
– not in the 5 GHz range like 802.11a
• Advantages
– compatible with 802.11b
– better range than 802.11a, for now
13. IEEE 802.11e
• Another upcoming standard for WLANs
– adds quality-of-service features to MAC layer of
802.11b compatible networks
• error correction
• better bandwidth management
– significantly improves multimedia performance
• works around RF interference
– handles interference by moving away from it
– i.e., moves to a new frequency when interference from a 2.4
GHz cordless phone is detected
15. IEEE 802.11 Physical Layer
• 802.11 Physical Layer Specifications
– include FHSS, DSSS, IR
• PLCP: Physical Layer Convergence Protocol
– interface used by the other physical layer specs
– maps data units into a suitable framing format
• PMD system: Physical Medium Dependent
– defines the characteristics/method of Tx/Rx data
through a wireless medium between 2 or more
stations
16. IEEE 802.11 Physical Layer
• Spread Spectrum
– spreads the transmitted signal over a wide range
of spectrum
– avoids concentrating power in a single narrow
frequency band
– noise makes this necessary so that receiver can
accurately decode the transmitted signal
– 2 major approaches to spread spectrum:
• FHSS: Frequency Hopping Spread Spectrum
• DSSS: Direct Sequence Spread Spectrum
17. IEEE 802.11 Data Link Layer
• 2 Sublayers
– Logical Link Control (LLC)
– Media Access Control (MAC)
• 802.11 uses the same 802.2 LLC
– same 48-bit addressing as other 802 LANs
• MAC address is 6 bytes or 48 bits
– allows for simple bridging to wired networks
• MAC sublayer is unique in 802.11
18. IEEE 802.11 MAC Sublayer
• MAC: Regulates access to the medium
• Wired IEEE 802 LANs use CSMA/CD
• 802.11 uses CSMA/CA
• CSMA: carrier sense multiple access
– CD: with collision detection
– CA: with collision avoidance
• Collision detection is not possible in 802.11
– near/far problem: can‟t transmit and “hear” a
collision at the same time
19. IEEE 802.11 MAC Sublayer
• CSMA/CA avoids collisions by explicit packet
acknowledgment (ACK)
– station wishing to transmit first senses the medium
– if no activity detected, station waits an additional,
random amount of time then transmits if the
medium is still free
– ACK packet is sent by receiving station to confirm
the data packet arrived intact
– collision assumed if sending station doesn‟t get
ACK, data is retransmitted after a random time
20. IEEE 802.11 MAC Sublayer
• Other unique features in 802.11
– IFS: Inter Frame Space
• time interval between frames
– Handling hidden stations (hidden-node problem)
• virtual carrier sense
– Power management functions
– Data security (MAC address, WEP)
• WEP: Wired Equivalent Privacy
– Multirate support
– Fragmentation / Defragmentation
21. Coordination Functions of MAC
• Determine when a station in a BSS is allowed
to transmit and when it may be able to receive
PDUs over the wireless medium
• Distributed Coordination Function (DCF)
– Provides support for asynchronous data transfer of
MAC SDUs on a best effort basis
– Contention Mode for all station
22. Coordination Functions of MAC
• Point Coordination Function
– Optional and sits on top of DCF
– May be implemented by an AP
– Connection-oriented time bound transfer of MAC
SDUs
– Contention and contenion-free periods
– Medium usage controlled by AP (synchronization
and timing)
23. DCF
• Basic access method
• Contention services for fair service to all stations
• All stations required to support DCF
• Based on CSMA-CA protocol
– All stations obliged to remain quiet for a certain minimum
period after a transmission has been completed called the
interframe space (IFS)
– High priority frames: SIFS
– PCF Priority access to the medium: PIFS
– DCF Interframe Space: DIFS
• Transmit data and management MPDUs
25. IEEE 802.11 Frame Types
• Three types of frames
– Control
• RTS, CTS, ACK, Contention-Free (CF), PS-Poll
• Used for handshaking and for positive acknowledgements during
the data transfer
– Management
• Probe request/response
• Station Association and Disassociation with the AP
• Timing and Synchronization
• Authentication / deauthentication
• Announcement traffic indication message (ATIM)
– sent after each frame
– Data
• Transmission of data
26. CSMA-CA operation
• A station is allowed to transmit an initial MAC
PDU under DCF if the station detects the medium
idle for a period DIFS or greater. If the station
detects medium busy, then it must calculate a
random backoff time to schedule a reattempt. A
station that has scheduled a reattempt monitors the
medium and decrements a counter each time an
idle contention slot expires. The station is allowed
to transmit when its backoff timer expires during
the contention period.
• Idle period after a DIFS period called contention
window (CW)
27. Handshaking in CSMA-CA
• Required when there is hidden station problem. If a
station A wants to send data frame to station B, station A
first sends a request-to-send (RTS) frame. If station B
receives the RTS frame, then B issues a clear-to-send
(CTS) frame. All stations within range of B receive CTS
frame and are aware that station A has been given
permission to send, so they remain quiet while station A
proceeds with its data frame transmission. If the data
frame arrives without error, station B responds with an
ACK. If two stations send RTS frames at the same time
and they collide at B then the stations must execute a
backoff to schedule a later attempt.
28. DIFS Contention
Window
PIFS
SIFS
DIFS
Busy Medium Next Frame
Wait for
Time
Defer Access
reattempt time
Basic CSMA-CA operation
29. IEEE 802.11 Topologies
• Three basic topologies for WLANs
– IBSS: Independent Basic Service Set
– BSS: Basic Service Set
– ESS: Extended Service Set
• Independent of type of PHY chosen
30. IEEE 802.11 IBSS
• IBSS: Independent Basic Service Set
– Peer-to-peer or ad-hoc network
– Wireless stations communicate directly with one
another
– Generally are not connected to a larger network
– No Access Point (AP)
31. IEEE 802.11 BSS
• BSS: Basic Service Set
– Infrastructure mode
– An AP connects clients to a wired network
32. BSS
• Defined as group of stations that coordinate
their access to the medium under a given
instance of the medium access control
• Area covered by BSS called Basic Service
Area (BSA)
– Analogous to a cell in cellular network
– Upto a diameter of tens of meters
33. BSS and Adhoc Wireless
Network
• Adhoc Network consists of group of
stations within range of each other
• Typically temporal in nature
• Can be formed spontaneously anywhere
• Disbanded after a limited period of time
34. IEEE 802.11 ESS
• ESS: Extended Service Set
– A set of BSSs interconnected by a distribution
system
– Consists of overlapping BSSs (each with an AP)
• DS connects APs together, almost always Ethernet
• ESS allows clients to seamlessly roam between APs
35. Access Point
• Similar in functionality to base station in a cellular
system
• ESS can also provide gateway access for wireless
users into a wired network such as Internet
– Such access accomplished via a device called portal
• Infrastructure network refers to combination of
BSSs, a distribution system and portals
36. Access Points (APs)
• To join an infrastructure BSS, a station
must select an AP and establish an
association with it
• This establishes mapping between station
and the AP
• Station can then send and receive data
messages via the AP
• Reassociation and Dissociation services
37. Access Points (APs)
• Usually connects wireless and wired
networks
– if not wired
• acts as an extension point
• Creation of ESS by overlapping AP coverage
– allows roaming operation
– APs should be on different channels
38. Access Points (APs)
• Capacity and Bandwidth
– Possible to keep these higher by using these
techniques
• Reducing size of coverage areas
• Reducing client-to-AP ratio
• Using bandwidth aggregation
– AP-to-client ratio
– load balancing
39. Access Points (APs)
• Roaming
– More than 1 AP provides signals to a single
client
– Client is responsible for choosing the best AP
• first, signal strength. second, network utilization.
– When signal in use degrades, client tries to find
another AP
• if found, tries to authenticate and associate
41. Access Points (APs)
• How to setup a secure access point
– Enable WEP or EAP
– Change SSID and disable broadcast
– Change the management password of your AP
• some have 2: read-only as well as read-write
– Use MAC address filtering
– Consider not using DHCP
• instead use fixed IP addresses for wireless NICs
– Consider other mechanisms for privacy
• PPTP, VPN, SSL, SSH
42. IEEE 802.11 Security
• Authentication
– Open system
– Shared key
• Authorization
– MAC address
• Privacy
– WEP: Wired Equivalent Privacy
44. Bluetooth
• Bluetooth must be able to:
• Recognize any other Bluetooth device in radio range
• Permit easy connection of these devices
• Be aware of the device types
• Support service discovery
• Support connectivity aware applications
• Examples of Bluetooth uses:
• Briefcase email: access email while the PC is still in the
briefcase; when PC receives an email, you are notified thru
the mobile phone. Use the mobile phone to browse the
email.
• Cordless desktop: connect your desktop/laptop cordlessly
to printers, scanner, keyboard, mouse, etc.
45. Bluetooth
• Bluetooth radio modules operate in the unlicensed ISM
band centered at at 2.45GHz. RF channels:2420+k MHZ,
k=0..78.
• Bluetooth devices within 10m of each other can share up
to 720kbps of capacity
• Projected cost for a Bluetooth chip is ~$5. Plus its low
power consumption, means you could literally place one
anywhere.
• Can operate on both circuit and packet switching modes,
providing both synchronous and asynchronous data
services
• It is intended to support an open-ended list of applications,
including data, audio, graphics and even video.
46. Bluetooth Architecture
• Up to 8 devices can communicate in a small network, called piconet.
• 10 piconets can coexist in the same coverage range of the Bluetooth
radio.
• Each piconet has 1 MASTER and the rest serve as SLAVES. SLAVES
within a piconet only have links to the MASTER.
• Multi-hop communication is obtained thru the scatternet.
47.
48. Bluetooth Limitations
• Does not address routing, most network functions are
pushed into the link layer
• Does not support multi-hop multicasting
• Does not address how to cope with mobility !
• The MASTER node is the bottleneck
• No. of nodes in piconet is limited
• Does not address power-saving methods done at upper
layers, above the link-layer
49. NS : Network Simulator
Any kind of network simulation
Including mobile and wireless network simulation
50. Outlines
Use NS to simulate wireless network
Extend NS to support mobile and wireless
application: Internal implementation
51. ns-2 overview
•Collection of various protocols at multiple layers
TCP(reno, tahoe, vegas, sack)
MAC(802.11, 802.3, TDMA)
Ad-hoc Routing (DSDV, DSR, AODV, TORA)
Sensor Network (diffusion, gaf)
Multicast protocols, Satellite protocols, and many others
•Codes are contributed from multiple research
communities
Good: Large set of simulation modules
Bad: Level of support and documentation varies
•The source code and documentation is currently
maintained by VINT project at ISI
52. Introduction
•ns-2 is an discrete event driven simulation
Physical activities are translated to events
Events are queued and processed in the order of their
scheduled occurrences
Time progresses as the events are processed
Time: 1.5 sec Time: 1.7 sec
1 2
Time: 2.0 sec Time: 1.8 sec
55. Network Components inside a
mobile node
Link Layer
ARP
Interface Queue
Mac Layer: IEEE 802.11
Network Interface
Radio Propagation Model
2
Friss-space attenuation(1/ r ) at near distance
2
Two ray Ground (1/ r ) at far distance
56. Mobile Node Modules
•Agent
Responsible for packet generations and receptions
Can think of it as an Application layer
CBR(Constant Bit Rate), TCP, Sink, FTP, etc.
•RTagent(DSDV, TORA, AODV) or DSR
Ad-hoc network routing protocols
Configure multi hop routes for packets
•LL (Link Layer)
Runs data link protocols
Fragmentation and reassembly of packet
Runs Address Resolution Protocol(ARP) to resolve IP
address to MAC address conversions
57. Mobile Node Modules (Continued)
•IFq (Interface Queue)
PriQueue is implemented to give priority to
routing protocol packets
Supports filter to remove packets destined to
specific address
•Mac Layer
IEEE 802.11 protocol is implemented
Uses RTS/CTS/DATA/ACK pattern for all unicast
pkts and DATA for broadcast pkts
58. Mobile Node Modules (Continued)
•NetIF (Network Interfaces)
Hardware interface used by mobilenode to access the
channel
Simulates signal integrity, collision, tx error
Mark each transmitted packet with transmission power,
wavelength etc.
•Radio Propagation Model
Uses Friss-space attenuation(1/r2) at near distance and
Two ray ground (1/r4) at far distance
Decides whether the packet can be received by the
mobilenode with given distance, transmit power and
wavelength
Implements Omni Directional Antenna module which has
unity gain for all direction
59. Wireless Simulation in ns-2 (Mobile Node
Diagram - DSDV)
Agent
(Src/Sink)
Demux
Port
Demux
Addr
RTagent
(DSDV)
LL ARP
IFq
MAC
Radio
Propagation NetIF
Model
Channel
60. Wireless Simulation in ns-2 (Mobile Node
Diagram - DSR)
Agent
(Src/Sink)
Demux
Port
DSR
LL ARP
IFq
MAC
Radio
Propagation NetIF
Model
Channel
61. Abstract the real mobile world into
your simulation
Node
Packets
Wireless channel and channel access
Forwarding and routing
Radio propagation model
Trace/Visualization
Event scheduler to make everything running
62. Implementing mobile node by
Extending “standard” NS node
Node Classifier:Forwarding
Agent: Protocol Entity
Routing Node Entry
LL ARP LL LL:Link layer object
IFQ:Interface queue
MAC Radio
Propagation
PHY Model
MAC MAC:Mac object
MobileNode PHY PHY:Net interface
CHANNEL
63. References
Anand Trivedi‟s IEEE 802.11 Page
– http://alpha.fdu.edu/~anandt/introduction.html
• IEEE 802.11 Working Group Page
– http://www.ieee802.org/11/
– Can download the 802 standards here for FREE
– Has links to all the latest 802.11 developments
• O‟Reilly
– http://oreilly.wirelessdevnet.com/
• http://wireless.telerama.com