This document is an assignment report for a course on data communication and networks. It contains an acknowledgement section thanking the course teacher and others for their support. The content section lists 12 topics that will be covered in the report, including introductions to packet switching, datagram and virtual circuit networks, encryption, and approaches to encryption across packet switching networks like link encryption and end-to-end encryption. Figures and tables are included to illustrate key concepts.
Embedded system in_automobiles_seminar_report_1234Ganesh Bv
Embedded systems are computer systems that monitor, respond to, or control external environments. They are used in many applications including automobiles, medical devices, wearables, and driverless vehicles. Embedded systems are small, have minimal user interfaces, and are designed to perform specific tasks in real-time. They are found in technologies like anti-lock braking systems, pacemakers, adaptive cruise control, and smart home appliances. As embedded systems become more advanced, they will enable remote health monitoring and driverless transportation capabilities.
Calm technology aims to reduce information overload by allowing users to select what information is central to their attention and what is peripheral. It was coined in 1995 by Mark Weiser and John Seeley Brown of Xerox PARC. Calm technology shifts focus to the periphery and uses ambient awareness through different senses to communicate without taking the user away from their task. It informs and calms users and makes use of their peripheral attention. Examples of calm technology include a tea kettle, inner office windows, sleep trackers, and smart badges - technologies that remain quiet until needed and provide information subtly and calmly.
Seminar on Advanced Driver Assistance Systems (ADAS).pptxMohit Nayal
Advanced Driver Assistance Systems (ADAS) use sensors and computer vision algorithms to detect objects, warn drivers of potential accidents, and take actions to avoid collisions. ADAS applications have evolved from simple cruise control in the 1950s to now include lane keeping, automatic emergency braking, and other systems. As ADAS becomes more advanced with 64-bit processors and neural networks, vehicles are progressing toward full autonomy. The goal of ADAS is to reduce the over 90% of accidents caused by human error by assisting drivers or taking control in dangerous situations.
Cortana is the code name for Microsoft's digital assistant being developed for Windows Phone. Cortana is based on an AI character from the Halo video game series named Cortana. Cortana will incorporate Bing SmartSearch features and allow natural voice interaction without predefined commands. Cortana will have a Notebook to store personal information from the user which it can use to offer personalized services by learning patterns and behaviors. Cortana aims to be helpful as a personal digital assistant for organizing daily activities alongside web searches.
This document provides an overview of biometrics technologies. It begins with an introduction to biometrics and then discusses the history of biometrics from ancient Egyptians and Chinese using fingerprints to modern systems being developed in the 1970s. The document outlines key characteristics biometrics must have such as universality and permanence. It then classifies and describes various biometric technologies including fingerprint, face, iris, voice, and signature recognition. Application examples are presented for areas like gaming, television control, and accessibility switches. The document concludes that biometrics provide a user-friendly way to interact with devices without passwords while continuing to develop as an emerging field.
IRJET- Accident Detection and Alerting SystemIRJET Journal
This document describes an accident detection and alerting system that uses sensors to detect vehicle accidents and sends alerts via SMS. The system uses an Arduino microcontroller connected to an accelerometer sensor to detect accidents based on vibrations. When an accident is detected, the Arduino reads location coordinates from an attached GPS receiver and sends an SMS with the coordinates and a Google Maps link to emergency contacts. This is intended to quickly notify authorities and help is sent to any victims. The system provides real-time accident detection and alerting to improve emergency response times.
Windows telah mengalami perkembangan dari versi 1.0 hingga 10 dengan menambah fitur-fitur baru dan meningkatkan kinerja. Mulai dari Windows 1.0 pada tahun 1985 hingga Windows 10 saat ini, Microsoft terus berinovasi untuk meningkatkan sistem operasinya.
Digital scent technology allows smells to be digitized and transmitted over the internet. It works by detecting smell molecules, indexing them, digitizing the scent file, and broadcasting it to receivers. Applications include scented movies, games, emails and websites. While it adds realism and immersion, issues include high costs, immaturity of the technology, and potential overuse of scents. Overall, digital scent has potential to enhance experiences once the technology is improved and costs lower.
Embedded system in_automobiles_seminar_report_1234Ganesh Bv
Embedded systems are computer systems that monitor, respond to, or control external environments. They are used in many applications including automobiles, medical devices, wearables, and driverless vehicles. Embedded systems are small, have minimal user interfaces, and are designed to perform specific tasks in real-time. They are found in technologies like anti-lock braking systems, pacemakers, adaptive cruise control, and smart home appliances. As embedded systems become more advanced, they will enable remote health monitoring and driverless transportation capabilities.
Calm technology aims to reduce information overload by allowing users to select what information is central to their attention and what is peripheral. It was coined in 1995 by Mark Weiser and John Seeley Brown of Xerox PARC. Calm technology shifts focus to the periphery and uses ambient awareness through different senses to communicate without taking the user away from their task. It informs and calms users and makes use of their peripheral attention. Examples of calm technology include a tea kettle, inner office windows, sleep trackers, and smart badges - technologies that remain quiet until needed and provide information subtly and calmly.
Seminar on Advanced Driver Assistance Systems (ADAS).pptxMohit Nayal
Advanced Driver Assistance Systems (ADAS) use sensors and computer vision algorithms to detect objects, warn drivers of potential accidents, and take actions to avoid collisions. ADAS applications have evolved from simple cruise control in the 1950s to now include lane keeping, automatic emergency braking, and other systems. As ADAS becomes more advanced with 64-bit processors and neural networks, vehicles are progressing toward full autonomy. The goal of ADAS is to reduce the over 90% of accidents caused by human error by assisting drivers or taking control in dangerous situations.
Cortana is the code name for Microsoft's digital assistant being developed for Windows Phone. Cortana is based on an AI character from the Halo video game series named Cortana. Cortana will incorporate Bing SmartSearch features and allow natural voice interaction without predefined commands. Cortana will have a Notebook to store personal information from the user which it can use to offer personalized services by learning patterns and behaviors. Cortana aims to be helpful as a personal digital assistant for organizing daily activities alongside web searches.
This document provides an overview of biometrics technologies. It begins with an introduction to biometrics and then discusses the history of biometrics from ancient Egyptians and Chinese using fingerprints to modern systems being developed in the 1970s. The document outlines key characteristics biometrics must have such as universality and permanence. It then classifies and describes various biometric technologies including fingerprint, face, iris, voice, and signature recognition. Application examples are presented for areas like gaming, television control, and accessibility switches. The document concludes that biometrics provide a user-friendly way to interact with devices without passwords while continuing to develop as an emerging field.
IRJET- Accident Detection and Alerting SystemIRJET Journal
This document describes an accident detection and alerting system that uses sensors to detect vehicle accidents and sends alerts via SMS. The system uses an Arduino microcontroller connected to an accelerometer sensor to detect accidents based on vibrations. When an accident is detected, the Arduino reads location coordinates from an attached GPS receiver and sends an SMS with the coordinates and a Google Maps link to emergency contacts. This is intended to quickly notify authorities and help is sent to any victims. The system provides real-time accident detection and alerting to improve emergency response times.
Windows telah mengalami perkembangan dari versi 1.0 hingga 10 dengan menambah fitur-fitur baru dan meningkatkan kinerja. Mulai dari Windows 1.0 pada tahun 1985 hingga Windows 10 saat ini, Microsoft terus berinovasi untuk meningkatkan sistem operasinya.
Digital scent technology allows smells to be digitized and transmitted over the internet. It works by detecting smell molecules, indexing them, digitizing the scent file, and broadcasting it to receivers. Applications include scented movies, games, emails and websites. While it adds realism and immersion, issues include high costs, immaturity of the technology, and potential overuse of scents. Overall, digital scent has potential to enhance experiences once the technology is improved and costs lower.
The document describes an adaptive cruise control (ACC) system that uses radar to detect vehicles ahead and control the host vehicle's speed to maintain a safe distance. The ACC system can operate in two modes: speed control mode, where it maintains the set speed when no target vehicle is present; and time gap control mode, where it adjusts speed to control the time gap between vehicles. The driver can engage and adjust the ACC system using buttons on the steering wheel to turn it on/off, set the speed or resume speed control, and adjust the time gap.
This document discusses fitness trackers, including their history, construction, and features. It provides an introduction to fitness trackers and how they differ from smartwatches. Key components that allow fitness trackers to function are described, including accelerometers that detect movement, optical heart rate sensors that measure heart rate through light, and proximity sensors. Advantages of fitness trackers include motivation for exercise and monitoring health metrics, while disadvantages include cost and potential inaccuracy of measurements.
The document discusses digital scent technology, which aims to transmit smells over the internet to enhance virtual experiences. Currently, online communications transmit sound and pictures, but smell is also an important sense that is not fully transmitted virtually. Digital scent technology uses hardware devices connected to computers to produce smells based on digital scent equations. This could allow transmitting smells to match movies, games, or messages. While an early prototype was created in the 1950s, digital scent technology has not been widely used. However, it may be implemented more in the future to make virtual experiences feel more complete by involving the sense of smell.
The document discusses autonomous vehicles and their potential benefits and challenges. It defines autonomous vehicles as vehicles that can travel from one point to another without human supervision. It notes that human error causes over 90% of automobile accidents and that autonomous vehicles could help reduce accidents by taking human error out of driving. The document outlines some of the key technologies used in autonomous vehicles, such as LIDAR, GPS, radar, ultrasonic sensors, video cameras, and a central computer. It discusses companies working on autonomous vehicle technologies like Google, Mercedes Benz, and Tesla. It also discusses some of the pros and cons of autonomous vehicles.
The document discusses the Chameleon Chip, a reconfigurable processor that can rewire itself dynamically to adapt to different software tasks. It contains reconfigurable processing fabric divided into slices that can be reconfigured independently. Algorithms are loaded sequentially onto the fabric for high performance. The chip architecture includes an ARC processor, memory controller, PCI controller, and programmable I/O. Its applications include wireless base stations, wireless local loops, and software-defined radio.
Light Peak technology is Intel's high-speed optical cable connectivity solution that uses fiber optics and can transfer data at speeds between 10Gb/s to 100Gb/s. It uses a universal connector and supports multiple protocols, allowing multiple devices to connect simultaneously. Light Peak aims to overcome limitations of current electrical connections by providing longer cable lengths, higher bandwidth, and more versatile connections.
Dokumen tersebut membahas tentang jaringan komputer, mulai dari pengenalan jaringan komputer, macam-macam jaringan komputer, perangkat jaringan, penggolongan jaringan berdasarkan topologi, dan macam-macam koneksi jaringan komputer.
This document defines packet switching and discusses several packet switching technologies. It begins by defining packet switching as dividing messages into packets that can follow different routes to the destination, where they are then recompiled. It then discusses three main packet switching technologies: TCP/IP, X.25, and Frame Relay. It provides details on each technology and notes that Frame Relay was implemented in Malaysia and replaced X.25 for connections within wide area networks.
Packet switching refers to protocols where messages are divided into packets before being transmitted. Each packet is transmitted individually and can take different routes to the destination. Once all packets arrive, they are recompiled into the original message. There are two main approaches: virtual circuits establish a pre-planned route before transmission, while datagrams treat each packet independently without connection setup. Virtual circuits provide sequencing but are less reliable if a node fails, while datagrams are more flexible but packets may arrive out of order.
The document discusses circuit switching and packet switching in wired area networks. It provides details on:
- Circuit switching networks require establishing dedicated circuits or paths between nodes before transmission can begin. This allows for constant transmission rates but limits flexibility.
- Packet switching breaks messages into packets that are transmitted independently through a network. Each node makes routing decisions for each packet. This allows variable transmission rates but can cause delays with high traffic.
- The two main techniques for packet switching are datagram, where each packet is routed independently, and virtual circuits, where a pre-planned route is set up before transmission.
- Other topics covered include space and time division switching used in circuit switching, characteristics of circuit switching nodes
Packet switching is a digital network communication method where data is broken into packets that are transmitted individually and can be routed differently within the network and reassembled at the destination. The packets in this example are being sent from computer A to computer B and are labeled with the destination, origin, and transmission order.
The document discusses packet switching and computer networks. It describes how packet switches enable packets to travel between hosts even without a direct connection by using buffers and queues. It explains the two main approaches to packet switching - connectionless datagram switching which uses destination addresses, and connection-oriented virtual circuit switching which establishes connections using labels. The key aspects of each approach like forwarding tables, signaling process, and connection setup and teardown are outlined.
There are three basic network topologies: bus, ring, and star. The bus topology shares a common connection but adding nodes reduces speed. Ring topology connects each node in a circle with data traveling in one direction. Star topology connects all nodes to a central hub or switch, so a failure of the central device takes down the whole network.
Packet switching provides virtual circuits between sites with contracted traffic rates. It shares bandwidth across these circuits more cost effectively than dedicated lines. Frame relay uses packet switching to multiplex logical data conversations over a single physical link using connection identifiers (DLCIs) assigned to each pair of connected devices. It establishes permanent or switched virtual circuits (PVCs or SVCs) between sites connected through a frame relay switch, which routes frames based on their DLCIs.
Here are full presentation slides on Network Topologies & different types of Network Topologies, advantages and disadvantages of different types of topologies & types of different devices being used in Networking or a Network System.
The document discusses the Interior Gateway Routing Protocol (IGRP) and Enhanced Interior Gateway Routing Protocol (EIGRP). IGRP was developed by Cisco in 1986 as an alternative to RIP routing, which had limitations like metric hop count and routing overhead. IGRP uses a composite metric including bandwidth, delay, reliability, and loading to determine the best path. It supports unequal cost load balancing and converges faster than RIP. EIGRP is an enhanced version of IGRP that uses the same metric system and supports features like variable length subnet masking.
Congestion control aims to prevent network overload by regulating data transmission. It is concerned with bottlenecks in packet-switched networks and sometimes there is no way to route around congested routers. Common congestion control techniques include flow control, router-based approaches like queue management algorithms, and host-based approaches where end hosts adjust their behavior in response to network conditions. Fair queuing algorithms like weighted fair queuing assign weights to flows to control bandwidth allocation.
This document discusses and compares several common network topologies: bus, star, ring, and mesh. It provides details on how each topology is configured and its advantages and disadvantages. The bus topology connects all devices to a common central cable, making it inexpensive but causing the entire network to fail if the cable fails. The star topology uses a central switch and point-to-point links, avoiding single points of failure but requiring more cabling. Ring topologies form a closed loop through each node but are expensive to install. Mesh topologies connect every node directly to every other for reliability but are also very expensive due to extensive cabling requirements.
This document discusses various techniques for congestion control in computer networks. It describes:
1. The difference between congestion control, which deals with overall traffic levels across a network, and flow control, which regulates traffic between two endpoints.
2. Common congestion control techniques like leaky bucket and token bucket algorithms, which shape traffic to prevent bursts that could cause congestion.
3. Other approaches like choke packets, where routers notify sources to reduce their transmission rates if a link becomes congested, and load shedding as a last resort if congestion cannot be avoided.
RIP adalah protokol routing distance-vector yang menentukan jalur berdasarkan jumlah hop. Protokol ini cocok untuk jaringan kecil karena memiliki batasan 16 hop dan melakukan update routing setiap 30 detik. RIP menggunakan beberapa timer seperti routing update, router invalid, hold down, dan router flush untuk mengelola informasi routing.
Packet-switching networks transfer information as packets that may experience random delays and loss. There are two main approaches: connectionless datagram service which routes packets independently, and connection-oriented virtual circuits which establish paths for packets belonging to a connection. Routing determines the best paths for packets using distributed algorithms that adapt to network changes. Large packet switches use techniques like self-routing, shared memory, and crossbar switches to efficiently route high volumes of packets.
The document describes an adaptive cruise control (ACC) system that uses radar to detect vehicles ahead and control the host vehicle's speed to maintain a safe distance. The ACC system can operate in two modes: speed control mode, where it maintains the set speed when no target vehicle is present; and time gap control mode, where it adjusts speed to control the time gap between vehicles. The driver can engage and adjust the ACC system using buttons on the steering wheel to turn it on/off, set the speed or resume speed control, and adjust the time gap.
This document discusses fitness trackers, including their history, construction, and features. It provides an introduction to fitness trackers and how they differ from smartwatches. Key components that allow fitness trackers to function are described, including accelerometers that detect movement, optical heart rate sensors that measure heart rate through light, and proximity sensors. Advantages of fitness trackers include motivation for exercise and monitoring health metrics, while disadvantages include cost and potential inaccuracy of measurements.
The document discusses digital scent technology, which aims to transmit smells over the internet to enhance virtual experiences. Currently, online communications transmit sound and pictures, but smell is also an important sense that is not fully transmitted virtually. Digital scent technology uses hardware devices connected to computers to produce smells based on digital scent equations. This could allow transmitting smells to match movies, games, or messages. While an early prototype was created in the 1950s, digital scent technology has not been widely used. However, it may be implemented more in the future to make virtual experiences feel more complete by involving the sense of smell.
The document discusses autonomous vehicles and their potential benefits and challenges. It defines autonomous vehicles as vehicles that can travel from one point to another without human supervision. It notes that human error causes over 90% of automobile accidents and that autonomous vehicles could help reduce accidents by taking human error out of driving. The document outlines some of the key technologies used in autonomous vehicles, such as LIDAR, GPS, radar, ultrasonic sensors, video cameras, and a central computer. It discusses companies working on autonomous vehicle technologies like Google, Mercedes Benz, and Tesla. It also discusses some of the pros and cons of autonomous vehicles.
The document discusses the Chameleon Chip, a reconfigurable processor that can rewire itself dynamically to adapt to different software tasks. It contains reconfigurable processing fabric divided into slices that can be reconfigured independently. Algorithms are loaded sequentially onto the fabric for high performance. The chip architecture includes an ARC processor, memory controller, PCI controller, and programmable I/O. Its applications include wireless base stations, wireless local loops, and software-defined radio.
Light Peak technology is Intel's high-speed optical cable connectivity solution that uses fiber optics and can transfer data at speeds between 10Gb/s to 100Gb/s. It uses a universal connector and supports multiple protocols, allowing multiple devices to connect simultaneously. Light Peak aims to overcome limitations of current electrical connections by providing longer cable lengths, higher bandwidth, and more versatile connections.
Dokumen tersebut membahas tentang jaringan komputer, mulai dari pengenalan jaringan komputer, macam-macam jaringan komputer, perangkat jaringan, penggolongan jaringan berdasarkan topologi, dan macam-macam koneksi jaringan komputer.
This document defines packet switching and discusses several packet switching technologies. It begins by defining packet switching as dividing messages into packets that can follow different routes to the destination, where they are then recompiled. It then discusses three main packet switching technologies: TCP/IP, X.25, and Frame Relay. It provides details on each technology and notes that Frame Relay was implemented in Malaysia and replaced X.25 for connections within wide area networks.
Packet switching refers to protocols where messages are divided into packets before being transmitted. Each packet is transmitted individually and can take different routes to the destination. Once all packets arrive, they are recompiled into the original message. There are two main approaches: virtual circuits establish a pre-planned route before transmission, while datagrams treat each packet independently without connection setup. Virtual circuits provide sequencing but are less reliable if a node fails, while datagrams are more flexible but packets may arrive out of order.
The document discusses circuit switching and packet switching in wired area networks. It provides details on:
- Circuit switching networks require establishing dedicated circuits or paths between nodes before transmission can begin. This allows for constant transmission rates but limits flexibility.
- Packet switching breaks messages into packets that are transmitted independently through a network. Each node makes routing decisions for each packet. This allows variable transmission rates but can cause delays with high traffic.
- The two main techniques for packet switching are datagram, where each packet is routed independently, and virtual circuits, where a pre-planned route is set up before transmission.
- Other topics covered include space and time division switching used in circuit switching, characteristics of circuit switching nodes
Packet switching is a digital network communication method where data is broken into packets that are transmitted individually and can be routed differently within the network and reassembled at the destination. The packets in this example are being sent from computer A to computer B and are labeled with the destination, origin, and transmission order.
The document discusses packet switching and computer networks. It describes how packet switches enable packets to travel between hosts even without a direct connection by using buffers and queues. It explains the two main approaches to packet switching - connectionless datagram switching which uses destination addresses, and connection-oriented virtual circuit switching which establishes connections using labels. The key aspects of each approach like forwarding tables, signaling process, and connection setup and teardown are outlined.
There are three basic network topologies: bus, ring, and star. The bus topology shares a common connection but adding nodes reduces speed. Ring topology connects each node in a circle with data traveling in one direction. Star topology connects all nodes to a central hub or switch, so a failure of the central device takes down the whole network.
Packet switching provides virtual circuits between sites with contracted traffic rates. It shares bandwidth across these circuits more cost effectively than dedicated lines. Frame relay uses packet switching to multiplex logical data conversations over a single physical link using connection identifiers (DLCIs) assigned to each pair of connected devices. It establishes permanent or switched virtual circuits (PVCs or SVCs) between sites connected through a frame relay switch, which routes frames based on their DLCIs.
Here are full presentation slides on Network Topologies & different types of Network Topologies, advantages and disadvantages of different types of topologies & types of different devices being used in Networking or a Network System.
The document discusses the Interior Gateway Routing Protocol (IGRP) and Enhanced Interior Gateway Routing Protocol (EIGRP). IGRP was developed by Cisco in 1986 as an alternative to RIP routing, which had limitations like metric hop count and routing overhead. IGRP uses a composite metric including bandwidth, delay, reliability, and loading to determine the best path. It supports unequal cost load balancing and converges faster than RIP. EIGRP is an enhanced version of IGRP that uses the same metric system and supports features like variable length subnet masking.
Congestion control aims to prevent network overload by regulating data transmission. It is concerned with bottlenecks in packet-switched networks and sometimes there is no way to route around congested routers. Common congestion control techniques include flow control, router-based approaches like queue management algorithms, and host-based approaches where end hosts adjust their behavior in response to network conditions. Fair queuing algorithms like weighted fair queuing assign weights to flows to control bandwidth allocation.
This document discusses and compares several common network topologies: bus, star, ring, and mesh. It provides details on how each topology is configured and its advantages and disadvantages. The bus topology connects all devices to a common central cable, making it inexpensive but causing the entire network to fail if the cable fails. The star topology uses a central switch and point-to-point links, avoiding single points of failure but requiring more cabling. Ring topologies form a closed loop through each node but are expensive to install. Mesh topologies connect every node directly to every other for reliability but are also very expensive due to extensive cabling requirements.
This document discusses various techniques for congestion control in computer networks. It describes:
1. The difference between congestion control, which deals with overall traffic levels across a network, and flow control, which regulates traffic between two endpoints.
2. Common congestion control techniques like leaky bucket and token bucket algorithms, which shape traffic to prevent bursts that could cause congestion.
3. Other approaches like choke packets, where routers notify sources to reduce their transmission rates if a link becomes congested, and load shedding as a last resort if congestion cannot be avoided.
RIP adalah protokol routing distance-vector yang menentukan jalur berdasarkan jumlah hop. Protokol ini cocok untuk jaringan kecil karena memiliki batasan 16 hop dan melakukan update routing setiap 30 detik. RIP menggunakan beberapa timer seperti routing update, router invalid, hold down, dan router flush untuk mengelola informasi routing.
Packet-switching networks transfer information as packets that may experience random delays and loss. There are two main approaches: connectionless datagram service which routes packets independently, and connection-oriented virtual circuits which establish paths for packets belonging to a connection. Routing determines the best paths for packets using distributed algorithms that adapt to network changes. Large packet switches use techniques like self-routing, shared memory, and crossbar switches to efficiently route high volumes of packets.
This document discusses network congestion and congestion control. It defines congestion as occurring when there are too many packets present in part of a subnet, degrading performance. Factors that can influence congestion include bursty traffic patterns, insufficient router memory or bandwidth, and slow router processing. Congestion control techniques aim to prevent or remove congestion through open-loop methods like traffic scheduling, or closed-loop methods using feedback to adjust system operations. Traffic-aware routing and admission control are also discussed as ways to minimize congestion.
The document provides an overview of the Border Gateway Protocol (BGP). It begins with general information about BGP, including that it is used for routing between autonomous systems and is classified as a path vector routing protocol. It then covers BGP theory in detail over several sections, explaining concepts like neighbors, messages, states, attributes and more. The document aims to provide thorough theoretical understanding needed to implement BGP in a lab.
Packet switching involves dividing data into packets that are transmitted through a network independently and reassembled at the destination. The X.25 protocol, developed in the 1960s, was one of the first standards used for packet switching networks. It establishes virtual circuits between nodes to transmit packets reliably while providing billing based on connection time. While widely used historically, X.25 has limitations for modern high-speed networks due to its overhead and lower transmission speeds compared to newer protocols like ATM and Frame Relay.
This document summarizes a presentation on congestion control in TCP/IP networks. It discusses basics of congestion and how it can be catastrophic if not handled. It then describes the basic strategies used by TCP to combat congestion, including slow start, congestion avoidance, detection, and illustration of algorithms like fast retransmit and recovery. Issues with wireless networks and variants of TCP like New Reno, Vegas, and Westwood are also summarized. The presentation proposes a new congestion control algorithm and discusses plans to simulate and test it.
This document summarizes a research paper on reducing packet loss in mobile ad hoc networks (MANETs). The paper discusses how MANETs are vulnerable to various security threats like black hole attacks that can cause packet dropping. It evaluates existing authentication schemes like ACK-based schemes that have overhead issues. The paper then proposes a modified ACK-based scheme using finite state automata to overcome decision ambiguity and minimize packet dropping while authenticating nodes in the MANET. Simulation results show that the proposed approach improves packet delivery ratio, throughput and reduces routing load compared to not using secure authentication.
1. The document describes applications of computer networking including resource access, data access, communication and data exchange, decentralization of data processing, and easy communication between organizations.
2. It then discusses internet security including client-server security using methods like passwords, firewalls, and encryption. Data and transaction security also uses encryption.
3. Various security methods are described for client/server and data/transaction security including password schemes, firewalls, and encryption techniques.
This document discusses applications of networking and internet security. It describes how networks can provide 1) access to resources regardless of physical location, 2) access to unique databases for local and remote users, and 3) communication and data exchange between users irrespective of time or location. It then discusses client-server security and data/transaction security when transmitting data over the internet. Specific security methods discussed include password schemes, firewalls, and encryption.
Hiding message from hacker using novel network techniquesPriyangaRajaram
we address the trouble of selective jamming attacks in wireless networks. In these assaults, the adversary is energetic best for a brief period of time, selectively concentrated on messages of excessive significance. We illustrate the benefits of selective jamming in phrases of network performance degradation and adversary effort with the aid of offering case research. A selective assault on TCP and one on routing. We show that selective jamming attacks can be launched with the aid of performing actual-time packet classification at the physical layer. To mitigate these attacks, we develop 3 schemes that prevent actual-time packet class via combining cryptographic primitives with physical-layer attributes. We analyze the security of our strategies and examine their computational and communication overhead.
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.
HOW TO DETECT MIDDLEBOXES: GUIDELINES ON A METHODOLOGYcscpconf
Internet middleboxes such as VPNs, firewalls, and proxies can significantly change handling of traffic streams. They play an increasingly important role in various types of IP networks. If end hosts can detect them, these hosts can make beneficial, and in some cases, crucial improvements in security and performance But because middle boxes have widely varying behavior and effects on the traffic they handle, no single technique has been discovered that can detect all of them.
Devising a detection mechanism to detect any particular type of middle box interference involves many design decisions and has numerous dimensions. One approach to assist with the
complexity of this process is to provide a set of systematic guidelines. This paper is the first attempt to introduce a set of general guidelines (as well as the rationale behind them) to assist researchers with devising methodologies for end-hosts to detect middle boxes by the end-hosts. The guidelines presented here take some inspiration from the previous work of other
researchers using various and often ad hoc approaches. These guidelines, however, are mainly based on our own experience with research on the detection of middle boxes. To assist
researchers in using these guidelines, we also provide an example of how to bring them into play for detection of network compression.
How to detect middleboxes guidelines on a methodologycsandit
Internet middleboxes such as VPNs, firewalls, and proxies can significantly change handling of
traffic streams. They play an increasingly important role in various types of IP networks. If end
hosts can detect them, these hosts can make beneficial, and in some cases, crucial improvements
in security and performance But because middleboxes have widely varying behavior and effects
on the traffic they handle, no single technique has been discovered that can detect all of them.
Devising a detection mechanism to detect any particular type of middlebox interference involves
many design decisions and has numerous dimensions. One approach to assist with the
complexity of this process is to provide a set of systematic guidelines. This paper is the first
attempt to introduce a set of general guidelines (as well as the rationale behind them) to assist
researchers with devising methodologies for end-hosts to detect middleboxes by the end-hosts.
The guidelines presented here take some inspiration from the previous work of other
researchers using various and often ad hoc approaches. These guidelines, however, are mainly
based on our own experience with research on the detection of middleboxes. To assist
researchers in using these guidelines, we also provide an example of how to bring them into
play for detection of network compression
This document proposes a Tiered Authentication scheme called TAM for multicast traffic in ad-hoc networks. TAM exploits network clustering to reduce overhead and ensure scalability. Within a cluster, one-way hash chains authenticate message sources by appending an authentication code to messages. Between clusters, messages include multiple authentication codes based on different keys from the source to authenticate it. TAM aims to securely deliver multicast traffic while addressing challenges like resource constraints and packet loss in ad-hoc networks.
The document summarizes research on preserving source location privacy in wireless sensor networks. It proposes using computer-based image recognition to analyze traffic patterns and detect modified data packets. The key points are:
1) Wireless sensor networks are vulnerable to traffic analysis attacks that can reveal the location of data sources. Existing solutions have limitations like increased energy use.
2) The paper proposes using computer-based image recognition to analyze traffic and identify packets whose delivery was delayed, indicating modification by an attacker.
3) If the attacking node is identified, it would be removed from the network. This approach aims to effectively preserve source location privacy against traffic analysis attacks.
Router Bridge Switch & Co. is a company founded in 2001 that researches networking devices. The document defines and describes routers, bridges, gateways, hubs, switches, and circuit switching versus packet switching. It also covers asynchronous transfer mode (ATM), a dedicated connection switching technology used to organize and transmit digital data.
SECURE ADHOC ROUTING PROTOCOL FOR PRIVACY RESERVATIONEditor IJMTER
Privacy preserving routing is crucial for some Ad hoc networks that require
stronger privacy protection. A number of schemes have been proposed to protect privacy in
Ad hoc networks. However, none of these schemes offer unobservability property since data
packets and control packets are still linkable and distinguishable in these schemes. In this
paper, we define stronger privacy requirements regarding privacy preserving routing in
mobile ad hoc networks. Then we propose an Unobservable Secure Routing scheme (USOR)
to offer complete unlinkability and content unobservability for all types of packets. USOR is
efficient as it uses a novel combination of group signature and ID-based encryption for route
discovery. Security analysis demonstrates that USOR can well protect user privacy against
both inside and outside attackers. We implement USOR on Network Security (NS2), and
evaluate its performance by comparing with Ad Hoc On demand Distance Vector Routing
(AODV) and MASK. The simulation results show that USOR not only has satisfactory
performance compared to AODV, but also achieves stronger privacy protection than existing
schemes like Mask.
Effectual Routine for Trilateral Authentication in Ad-hoc Networks using Mult...IOSR Journals
This document proposes a protocol for trilateral authentication in ad-hoc networks using multicast conventions. It introduces a central authority that manages key authentication and certification to increase security and reliability. Nodes are grouped into clusters, each with a cluster head. For similar clusters, authentication uses time asymmetry based on TESLA. For cross-cluster traffic, it uses secret information asymmetry where the source sends packets to cluster heads, which relay to members. Evaluation shows the central authority uses less memory than previous methods and the protocol has higher efficiency.
SECURE LOCATION BASED ROUTING FOR MANETSAnkur Singhal
The video demonstrates sending the file from source to the destination by initially encrypting it using multihops and then decrypting it at the receiver's end
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
“Optimizing the data transmission between multiple nodes during link failure ...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
The document summarizes key aspects of the transport layer, including the transport service it provides to upper layers, connection-oriented and connectionless transport services, and transport service primitives. It discusses transport layer protocols like TCP and UDP, explaining how TCP uses a three-way handshake to establish connections and addressing challenges like congestion control, delayed packet delivery, and host crashes.
This document discusses various control structures in C programming language including conditional statements like if-else and switch case, loops like for, while and do-while loops, and jump statements like break, continue, return and goto. It provides examples of each structure and explains their usage and functionality. The key control structures covered are if-else, switch case, for, while, do-while loops, and how to use break, continue, return and goto statements to control program flow in C programs.
The document provides an overview of the fundamentals of the C programming language including its history, development environment, basic program structure, data types, constants, variables, input/output functions, and more. It describes how C was developed in the 1970s and became widely popular. It also explains key elements like preprocessor directives, functions, statements, and basic syntax rules for writing C programs.
1. Functions allow programmers to break complex problems into smaller, discrete tasks, making code more modular and reusable. Functions perform specific tasks and can optionally return values or receive parameters.
2. There are two types of functions - predefined functions from standard libraries like stdio.h and math.h, and user-defined functions created for specialized tasks. Functions have a name, parameters, return type, and body.
3. Functions improve code organization and readability. They separate implementation from interface and allow code reuse. Parameters can be passed by value, where copies are used, or by reference, where the function can modify the original arguments.
This document implements Strassen's algorithm for matrix multiplication. It prompts the user to input the sizes of matrices A and B, and then the elements of each matrix. It then calculates 7 products, P1 through P7, which are used to calculate the elements of the resulting matrix C according to Strassen's formulas. The calculated matrix C is then output.
RAID (Redundant Arrays of Independent Disks) uses multiple disk drives to increase performance and reliability. It distributes data across several disks that act as one large drive. There are different RAID levels that offer varying degrees of performance and fault tolerance. RAID levels 0 through 6 were described, with RAID 0 offering striping for performance but no redundancy, RAID 1 using mirroring for redundancy but no performance gain, and RAID levels 3 through 6 employing striping with varying parity techniques for performance and redundancy.
The document discusses strings in C++. It defines strings, describes how to declare and manipulate string objects using the string class in C++, and lists common string operations like concatenation, comparison, extracting substrings, searching/finding patterns, and inserting/replacing/deleting substrings. It also discusses how to work with C-style strings using functions in the <strings.h> library and character functions in <ctype.h>.
This document discusses file handling in C. It defines a file, outlines the basic steps to process a file which are to open, read/write, and close it. The basic file operations like fopen, fclose, fread, fwrite are introduced. It also covers file open modes, additional modes like r+, w+, a+, and functions to work with files like fprintf, fscanf, getc, putc. Examples are provided to demonstrate reading, writing, seeking within a file using functions like fread, fwrite, fseek, ftell.
1. " ASSIGNMENT REPORT"
Under the guidance of :-
Usha Mary Sharma (Asst. Professor),
course teacher for, Data Communication and Networks -1(MCCSGC3009)
Don Bosco College of Engineering and Technology, Azara, Guwahati, Assam
2. Page 2
Acknowledgement
I take this opportunity to express my profound gratitude and
deep regards to my guide Usha Mary Sharma (Asst. Professor),
for his exemplary guidance, monitoring and constant
encouragement throughout the course of this thesis. The
blessing, help and guidance given by him time to time shall
carry me a long way in the journey of life on which I am about
to embark.
I also thank almighty, my parents, and friends for their constant
encouragement without which this assignment would not be possible.
BIKASH KUMAR DHAL
DC2013MCA0028 (MCA-3)
3. Page 3
Content
Sl no. Topic Page No.
1. Introduction to Packet Switching, What is packet
Switching ? , DATAGRAM NETWORKS,
figure : 1 Datagram Network
4
2. Efficiency Of DATAGRAM ,
VIRTUAL-CIRCUIT NETWORKS ,
Figure : 2 Virtual network
5
3. Efficiency in virtual-circuit network ,
Introduction Of Encryption, Encryption 6
4. Introduction to Encryption Continue , Figure : 3 Stage
of Encryption and Decryption
7
5.
Why Encryption Across packet Switching Networks
is Important ? , Figure : 4 Points of Vulnerability
8,9
6. Approaches of Encryption Across packet Switching
Networks , Figure : 5 Packet Switching Networks
10
7. Link Encryption , End to End Encryption . 11
8. End - to - End Encryption continue , Logical
Placement of End-to-End Encryption Function
12
9. Figure : 6 Encryption with Store-and-Forward
communication
13
10
Figure : 7 Relationship between Encryption and
Protocol Levels
14
11 Table : 1 Different characteristics between Link
Encryption And End-to-End Encryption
15
12 Conclusion 16
13 Glossary / Acronyms 17
14 Bibliography 18
4. Page 4
Introduction to Packet Switching
What is packet Switching?
In a packet switched network , data transmitted in potential variable length blocks called Packets.
The maximum length of the packet is established by a network . Longer transmission are broken
up into multiple packets Each packet not only contain data but header with control information
(Such as priority code , source and destination address).The packet are sent over the network
node to node
Basically it has two Approaches
1. DATAGRAM NETWORKS
2. VIRTUAL-CIRCUIT NETWORKS
DATAGRAM NETWORKS
In a datagram network, each packet is treated independently of all others. Even if a packet is
part of a multi-packet transmission, the network treats it as though it existed alone. Packets in
this approach are referred to as datagrams. Datagram switching is normally done at the network
layer.
figure : 1 Datagram Network
In this example, all four packets (or datagrams) belong to the same message, but may travel
different paths to reach their destination. This is so because the links may be involved in carrying
packets from other sources and do not have the necessary bandwidth available to carry all the
packets from A to X. This approach can cause the datagrams of a transmission to arrive at their
destination out of order with different delays between the packets. Packets may also be lost or
dropped because of a lack of resources.
5. Page 5
.
Efficiency Of DATAGRAM
The efficiency of a datagram network is better than that of a circuit-switched network resources
are allocated only when there are packets to be transferred. If a source sends a packet and there is
a delay of a few minutes before another packet can be sent, the resources can be reallocated
during these minutes for other packets from other sources.
VIRTUAL-CIRCUIT NETWORKS
In Virtual - circuit approach , the relationship between all packets belonging to a message or
session is preserved . A single route is chosen between sender and receiver at the beginning of
the session .When data are sent all packets of transmission travel one after another along that
route.
Figure : 2 Virtual network
Figure 2 (Virtual network)is an example of a virtual-circuit network. The network has switches
that allow traffic from sources to destinations. A source or destination can be a computer, packet
switch, bridge, or any other device that connects other networks.
6. Page 6
Efficiency in virtual-circuit network
As we said before, resource reservation in a virtual-circuit network can be made during the setup
or can be on demand during the data transfer phase. In the first case, the delay for each packet is
the same; in the second case, each packet may encounter different delays. There is one big
advantage in a virtual-circuit network even if resource allocation is on demand. The source can
check the availability of the resources, without actually reserving it. Consider a family that wants
to dine at a restaurant. Although the restaurant may not accept reservations (allocation of the
tables is on demand), the family can call and find out the waiting time. This can save the family
time and effort.
Introduction Of Encryption
Encryption
Encryption is the conversion of data into a form, called a Ciphertext , that cannot be easily
understood by unauthorized people. Decryption is the process of converting encrypted data back
into its original form, so it can be understood.
The use of encryption/decryption is as old as the art of communication. In wartime, a cipher,
often incorrectly called a code, can be employed to keep the enemy from obtaining the contents
of transmissions. (Technically, a code is a means of representing a signal without the intent of
keeping it secret; examples are Morse- Code and ASCII.) Simple ciphers include the substitution
of letters for numbers, the rotation of letters in the alphabet, and the "scrambling" of voice
signals by inverting the sideband frequencies. More complex ciphers work according to
sophisticated computer algorithms that rearrange the data bits in digital signals.
In order to easily recover the contents of an encrypted signal, the correct decryption key is
required. The key is an algorithm that undoes the work of the encryption algorithm.
Alternatively, a computer can be used in an attempt to break the cipher. The more complex the
encryption algorithm, the more difficult it becomes to eavesdrop on the communications without
access to the key.
Encryption/decryption is especially important in wireless communications. This is because
wireless circuits are easier to tap than their hard-wired counterparts. Nevertheless
,encryption/decryption is a good idea when carrying out any kind of sensitive transaction, such as
a credit-card purchase online, or the discussion of a company secret between different
departments in the organization. The stronger the cipher -- that is, the harder it is for
unauthorized people to break it -- the better, in general. However, as the strength of
encryption/decryption increases, so does the cost.
7. Page 7
Introduction to Encryption Continue
In recent years, a controversy has arisen over so-called strong encryption. This refers to ciphers
that are essentially unbreakable without the decryption keys. While most companies and their
customers view it as a means of keeping secrets and minimizing fraud, some governments view
strong encryption as a potential vehicle by which terrorists might evade authorities. These
governments, including that of the United States, want to set up a key-escrow arrangement. This
means everyone who uses a cipher would be required to provide the government with a copy of
the key. Decryption keys would be stored in a supposedly secure place, used only by authorities,
and used only if backed up by a court order. Opponents of this scheme argue that criminals could
hack into the key-escrow database and illegally obtain, steal, or alter the keys. Supporters claim
that while this is a possibility, implementing the key escrow scheme would be better than doing
nothing to prevent criminals from freely using encryption/decryption
Figure : 3 Stage of Encryption and Decryption
8. Page 8
Why Encryption Across packetSwitching Networks is Important ?
As an example, consider a user workstation in a typical business organization. Figure 4.0
suggests the types of communications facilities that might be employed by such a workstation
and therefore gives an indication of the points of vulnerability.
Figure : 4 Points of Vulnerability
Factors of vulnerability
In most organizations, workstations are attached to local area networks (LANs).
Typically, the user can reach other workstations, hosts , and servers directly on the LAN
or on other LANs in the same building that are interconnected with bridges and routers.
Here, then, is the first point of vulnerability. In this case, the main concern is
eavesdropping by another employee. Typically, a LAN is a broadcast network:
Transmission from any station to any other station is visible on the LAN medium to all
stations . Data are transmitted in the form of frames , with each frame containing the
source and destination address. An eavesdropper can monitor the traffic on the LAN and
capture any traffic desired on the basis of source and destination addresses. If part or all
of the LAN is wireless, then the potential for eavesdropping is greater.
9. Page 9
Furthermore, the eavesdropper need not necessarily be an employee in the building. If the
LAN, through a communications server or one of the hosts on the LAN, offers a dial-in
capability, then it is possible for an intruder to gain access to the LAN and monitor
traffic.
Access to the outside world from the LAN is almost always available in the form of a
router that connects to the Internet, a bank of dial-out modems, or some other type of
communications server. From the communications server, there is a line leading to a
wiring closet . The wiring closet serves as a patch panel for interconnecting internal data
and phone lines and for providing a staging point for external communications.
The wiring closet itself is vulnerable. If an intruder can penetrate to the closet, he or she
can tap into each wire to determine which are used for data transmission. After isolating
one or more lines, the intruder can attach a low-power radio transmitter. The resulting
signals can be picked up from a nearby location (e.g., a parked van or a nearby building).
Several routes out of the wiring closet are possible. A standard configuration provides
access to the nearest central office of the local telephone company. Wires in the closet are
gathered into a cable, which is usually consolidated with other cables in the basement of
the building. From there, a larger cable runs underground to the central office.
In addition, the wiring closet may provide a link to a microwave antenna, either an earth
station for a satellite link or a point-to-point terrestrial microwave link. The antenna link
can be part of a private network, or it can be a local bypass to hook in to a long-distance
carrier.
The wiring closet may also provide a link to a node of a packet-switching network. This
link can be a leased line, a direct private line, or a switched connection through a public
telecommunications network. Inside the network, data pass through a number of nodes
and links between nodes until the data arrive at the node to which the destination end
system is connected.
An attack can take place on any of the communications links. For active attacks, the
attacker needs to gain physical control of a portion of the link and be able to insert and
capture transmissions. For a passive attack, the attacker merely needs to be able to
observe transmissions. The communications links involved can be cable (telephone
twisted pair, coaxial cable, or optical fiber), microwave links, or satellite channels.
Twisted pair and coaxial cable can be attacked using either invasive taps or inductive
devices that monitor electromagnetic emanations. Invasive taps allow both active and
passive attacks, whereas inductive taps are useful for passive attacks. Neither type of tap
is as effective with optical fiber, which is one of the advantages of this medium. The fiber
does not generate electromagnetic emanations and hence is not vulnerable to inductive
taps. Physically breaking the cable seriously degrades signal quality and is therefore
detectable. Microwave and satellite transmissions can be intercepted with little risk to the
attacker. This is especially true of satellite transmissions, which cover a broad geographic
area. Active attacks on microwave and satellite are also possible, although they are more
difficult technically and can be quite expensive.
10. Page 10
Approaches of Encryption Across packetSwitching Networks
There are two major approaches :
1. Link Encryption
2. End to End Encryption .
Figure : 5 Packet Switching Networks
11. Page 11
Link Encryption
With link encryption, each vulnerable communications link is equipped on both ends with an
encryption device. Thus, all traffic over all communications links is secured. Although this
recourse requires a lot of encryption devices in a large network, its value is clear. One of its
disadvantages is that the message must be decrypted each time it enters a packet switch because
the switch must read the address (logical connection number) in the packet header in order to
route the packet. Thus, the message is vulnerable at each switch. If working with a public packet
switching network, the user has no control over the security of the nodes. Several implications of
link encryption should be noted. For this strategy to be effective, all the potential links in a path
from source to destination must use link encryption. Each pair of nodes that share a link should
share a unique key, with a different key used on each link. Thus, many keys must be provided.
However, each key must be distributed to only two nodes.
End - to - End Encryption
With end-to-end encryption, the encryption process is carried out at the two end systems. The
source host or terminal encrypts the data. The data in encrypted form are then transmitted
unaltered across the network to the destination terminal or host. The destination shares a key
with the source and so is able to decrypt the data. This plan seems to secure the transmission
against attacks on the network links or switches. Thus, end-to-end encryption relieves the end
user of concerns about the degree of security of networks and links that support the
communication. There is, however, still a weak spot.
Consider the following situation. A host connects to an X.25 packet-switching network, sets up a
virtual circuit to another host, and is prepared to transfer data to that other host by using end-to-
end encryption. Data are transmitted over such a network in the form of packets that consist of a
header and some user data. What part of each packet will the host encrypt? Suppose that the host
encrypts the entire packet, including the header. This will not work because, remember, only the
other host can perform the decryption. The packet switching node will receive an encrypted
packet and be unable to read the header. Therefore, it will not be able to route the packet. It
follows that the host may encrypt only the user data portion of the packet and must leave the
header in the clear. Thus, with end-to-end encryption, the user data are secure. However, the
traffic pattern is not, because packet headers are transmitted in the clear.
On the other hand, end-to-end encryption does provide a degree of authentication. If two end
systems share an encryption key, then a recipient is assured that any message that it receives
comes from the alleged sender, because only that sender shares the relevant key. Such
authentication is not inherent in a link encryption scheme.
12. Page 12
End - to - End Encryption continue
To achieve greater security, both link and end-to-end encryption are needed, as is shown in
Figure 5 (Packet Switching Networks). When both forms of encryption are employed, the host
encrypts the user data portion of a packet using an end-to-end encryption key. The entire packet
is then encrypted using a link encryption key. As the packet traverses the network, each switch
decrypts the packet, using a link encryption key to read the header, and then encrypts the entire
packet again for sending it out on the next link. Now the entire packet is secure except for the
time that the packet is actually in the memory of a packet switch, at which time the packet header
is in the clear.
Logical Placement of End-to-End Encryption Function
With link encryption, the encryption function is performed at a low level of the communications
hierarchy. In terms of the Open Systems Interconnection (OSI) model, link encryption occurs at
either the physical or link layers. For end-to-end encryption, several choices are possible for the
logical placement of the encryption function. At the lowest practical level, the encryption
function could be performed at the network layer. Thus, for example, encryption could be
associated with X.25, so that the user data portion of all X.25 packets is encrypted. With
network-layer encryption, the number of identifiable and separately protected entities
corresponds to the number of end systems in the network. Each end system can engage in an
encrypted exchange with another end system if the two share a secret key. All the user processes
and applications within each end system would employ the same encryption scheme with the
same key to reach a particular target end system. With this arrangement, it might be desirable to
off-load the encryption function to some sort of front-end processor (typically a communications
board in the end system). Deployment of encryption services on end-to-end protocols, such as a
network-layer X.25 or TCP, provides end-to-end security for traffic within a fully integrated
internetwork. However, such a scheme cannot deliver the necessary service for traffic that
crosses internetwork boundaries, such as electronic mail, electronic data interchange (EDI), and
file transfers.
13. Page 13
Figure : 6 Encryption with Store-and-Forward communication
Figure: 6 illustrates the issues involved. In this example, an electronic mail gateway is used to
interconnect an internetwork that uses an OSI - Based architecture with one that uses a TCP/IP-
based architecture. In such a configuration, there is no end-to-end protocol below the application
layer. The transport and network connections from each end system terminate at the mail
gateway, which sets up new transport and network connections to link to the other end system.
Furthermore, such a scenario is not limited to the case of a gateway between two different
architectures. Even if both end systems use TCP/IP or OSI, there are plenty of instances in actual
configurations in which mail gateways sit between otherwise isolated internetworks. Thus, for
applications like electronic mail that have a store-and-forward capability, the only place to
achieve end-to-end encryption is at the application layer.
A drawback of application-layer encryption is that the number of entities to consider
increases dramatically. A network that supports hundreds of hosts may support thousands
of users and processes. Thus, many more secret keys need to be generated and
distributed.
An interesting way of viewing the alternatives is to note that as we move up the
communications hierarchy, less information is encrypted but it is more secure. Figure 7
highlights this point, using the TCP/IP architecture as an example. In the figure, an
application-level gateway refers to a store-and-forward device that operates at the
application level. Unfortunately, most TCP/IP documents use the term gateway to refer to
what is more commonly referred to as a router .
14. Page 14
Figure : 7 Relationship between Encryption and Protocol Levels
With application-level encryption (Figure 7.a), only the user data portion of a TCP segment is
encrypted. The TCP, IP, network-level, and link-level headers and link-level trailer are in the
clear. By contrast, if encryption is performed at the TCP level (Figure 7.b), then, on a single end-
to-end connection, the user data and the TCP header are encrypted. The IP header remains in the
clear because it is needed by routers to route the IP datagram from source to destination. Note,
however, that if a message passes through a gateway, the TCP connection is terminated and a
new transport connection is opened for the next hop. Furthermore, the gateway is treated as a
destination by the underlying IP. Thus, the encrypted portions of the data unit are decrypted at
the gateway. If the next hop is over a TCP/IP network, then the user data and TCP header are
encrypted again before transmission. However, in the gateway itself the data unit is buffered
entirely in the clear. Finally, for link-level encryption (Figure 7.c), the entire data unit except for
the link header and trailer is encrypted on each link, but the entire data unit is in the clear at each
router and gateway. The figure actually shows but one alternative. It is also possible to encrypt
part or even all of the link header and trailer except for the starting and ending frame flags.
15. Page 15
Characteristics of Link and End-to-End Encryption
Characteristics of Link and End-to-End Encryption
Link Encryption End-to-End Encryption
Security within End Systems and Intermediate Systems
Message exposed in sending host Message encrypted in sending
host
Message exposed in intermediate nodes Message encrypted in
intermediate nodes
Role of User
Applied by sending host Applied by sending process
Transparent to user User applies encryption
Host maintains encryption facility User must determine algorithm
One facility for all users Users selects encryption scheme
Can be done in hardware Software implementation
All or no messages encrypted User chooses to encrypt, or not,
for each message
Implementation Concerns
Requires one key per (host-intermediate node) pair and
(intermediate node-intermediate node) pair
Requires one key per user pair
Provides host authentication Provides user authentication
Table : 1 Different characteristics between Link Encryption And End-to-End Encryption
16. Page 16
Conclusion
From the assignment we can have concrete knowledge of Packet Switching and Encryption
Basically Two Approaches Of Packet Switching
1. DATAGRAM NETWORKS
2. VIRTUAL-CIRCUIT NETWORKS
Advantages of Both the Approaches
How Encryption is helping in packet Switching in networks ? How Encryption is helping us from
unseen threats , and how can we stop an intruder or an unauthorized person from getting our
data
public key and Private key: This is a pair of keys that have seen selected so that if one is used
for encryption , the other is used for decryption . The exact transformation is performed by the
algorithm depend on the public or private key that is provided as input.
Ciphertext : This is scrambled message produced as output . It depends on the plain text and the
key . For a given message ,tow different keys will produce two different Ciphertext
Two process used in PSTN (Packet Switching Network)
1. Link Encryption
2. End to End Encryption .
17. Page 17
Glossary / Acronyms
PSTN - Packet Switching Networks
IP- Internetworking Protocol
UDP- User Datagram Protocol
TCP- Transmission Control Protocol
DES- Data Encryption standard
Application Layer- The Seventh Layer OSI model ; Provides access to networks.
Datagram approach Packet Switching - A data transmission method in which each data unit
is independent of others
Encryption- Converting a message into unintelligible form that is unreadable unless decrypted.
Decryption- Recovery Of original data from the Encrypted Data
Public key And Private key: This is a pair of keys that have seen selected so that if one is used
for encryption , the other is used for decryption . The exact transformation is performed by the
algorithm depend on the public or private key that is provided as input.
Ciphertext : This is scrambled message produced as output . It depends on the plain text and the
key . For a given message ,two different keys will produce two different Ciphertext .
Virtual-Circuit approach Packet Switching - A Packet Switching method in which all
packets of a message or session follow exact same route .
18. Page 18
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