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The document provides an overview of ad-hoc networking and wireless protocols. It discusses how ad-hoc networks are formed spontaneously without any centralized administration between wireless devices. Various wireless transmission standards for ad-hoc networking are described such as Bluetooth, IEEE 802.11, and IrDA. Example applications including sensor networks and mobile commerce are mentioned. Challenges with ad-hoc networking like security, scalability and power consumption are outlined. Specific ad-hoc routing protocols including AODV and DSR are explained and compared.

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MBA Admission in India By: admission.edhole.com
AAdd--hhoocc NNeettwwoorrkkiinngg &&WWPPAANN admission.edhole.com
3 Outline •Ad-Hoc Networking? •Why? •What? •How? •When? : Past, Present, Future admission.edhole.com
4 Scenario •The advent of cheap microprocessors and wireless technologies •Trend: ~1000 computer devices/person by 2010 admission.edhole.com
5 Use Cases admission.edhole.com
Possibilities •Telephones (cellular, cordless, other) •Cordless multimedia (headsets, speakers, mic.) •Portable computers (Laptops, desktop, other) •Cordless computer peripherals (keyboard, mouse) •LAN – Local Area Network peripherals (printer, fax) •PDAs - Personal Digital Assistants (palm top/pilot) •Digital cameras 6 admission.edhole.com
7 Ad-…what? Ad-hoc network… …a LAN or other small network, …with wireless connections …devices are part of the network only for the duration of a communications session Or …while in close proximity to the network admission.edhole.com
8 Ad-hoc Networking Collection of wireless mobile nodes (devices) dynamically forming a temporary network without the use of any existing network infrastructure or centralized administration An ubiquitous type of computing often referred to as pervasive/invisible computing •Ubiquitous: Present, appearing, or found everywhere… •Pervasive: Spread through or into every part admiossf…ion.edhole.com
Properties •Requires devices to cooperate autonomously •Without user intervention •Rapid self-organizing wireless network •Independent of infrastructure •Heterogeneous & adaptive admission.edhole.com 9
10 Why? Microprocessor embedding trend in: •cellular phones, car stereos, televisions, VCRs, watches, GPS (Global Positioning System) receivers, digital camera. •Ensembles of computational devices for: •environmental monitoring •personal area networks adm•gisesoiopnh.eydhsioclea.lc ommeasurement
11 How? Transmission Standards: 1. Piconet 2. HomeRF (Radio Frequency) 3. IEEE 802.11 Wireless LAN WG (Working Group) 4. Bluetooth SIG (Special Interest Group) • These above use radio waves from licence-exempt ISM (Industrial, Scientific and Medical) frequency band - around 2.4 GHz admission.edhole.com 5. IrDA (InfraRed Data Association) • which uses infrared instead of radio waves
12 Piconet • A general purpose, low-powered, ad-hoc network • It allows two devices near each other to inter-operate • These devices can be either mobile or fixed • The range is said admission.edhole.com to be reasonably short
13 HomeRF Uses Shared Wireless Access Protocol (SWAP) system • carries both voice and data traffic • inter-operate with the PSTN (Public Switched Telephone Network) and the Internet • the range covers typical home and yard admission.edhole.com
IEEE 802.11 Wireless LAN The principles of Wireless Local Area Network (WLAN) are defined in IEEE 802.11 standard • It defines two different topologies: ad-hoc network and infrastructure network • This ad-hoc network is able to use only created wireless connection instead of fixed adminisfsrioans.terduhoclteu.croem 14
15 Bluetooth • The code name for an open specification for short-range wireless connectivity • Effortless, instant wireless connections between a wide range of communication devices in a small environment • The BT range restricts the environment to about 10 meters • Used in virtually any mobile device like that can have Bluetooth admission.edhole.com radios integrated into them
IrDA • based on technology similar to the remote 16 control devices • high-speed short range, point-to-point cordless data transfer • in-room cordless peripherals to host-PC • maturity and standardization activities advantage over radio • line-of-sight admission.edhole.c roemquirement disadvantage
17 Wireless comparison admission.edhole.com
Applications Some current deployments, research and prospects •Cybiko •Sensor Networks e.g. “Smart Dust” •Mobile Commerce (M-Commerce) - proposed admission.edhole.com 18
19 Cybiko •like a Palm Pilot, except with free games and and is designed for entertainment unlike palms which are really meant as organisers •wireless connectivity RF transmitter for text chat • when cybikos network together, they relay messages to other cybikos, which allows the range to be increased • up to 100 cybikos can be networked in this way, and 3000 cybikos can be online in one area at once before admission.the ISM edhole.RF band com gets full • it will have a range of approx. 1km outside, 500m inside
20 Sensor Nets – “Smart Dust ” I • thousands to millions of small sensors form self-organizing wireless networks • consists of nodes, small battery powered devices, that communicate with a more powerful base admission.station, edhole.which com in turn is connected to an outside network.
21 Sensor Nets – “Smart Dust ” II Metrics: CPU 8-bit, 4MHz Storage 8KB instruction flash 512 bytes RAM 512 bytes EEPROM Communication 916 MHz radio Bandwidth 10 kbps Operating TinyOS System OS code space 3500 bytes Available code space •Node to base sta4ti5o0n0 cbyotmesmunication, e.g. sensor readings •Base station to node communication, e.g. specific requests •admission.Base station edhole.to all nodes, com e.g. routing beacons, queries or reprogramming of the entire network
M-Commerce • Mobile phones to extend the possibilities of commerce • make commerce platforms more important • electronic and mobile commerce transactions will be open for wide markets 22 admission.edhole.com
Issues & Interests • What do you see as the next interesting things in mobile computing? • What potential do you see for wireless networks? • What do you see as the hardest things for us to address? Security for one! • If you could wish for one key piece of technology to come true (for mobility), what would it be? 23 admission.edhole.com
Ad Hoc Networks and Their Protocols: admission.edhole.com
Ad Hoc Networking A mode of loosely connected networking characterized by the following qualities:  lack of fixed infrastructure  peer-to-peer (all nodes act as routers)  multi-hop routing  frequent connection / topology changes 25 admission.edhole.com
26 Applications of Ad Hoc  Earliest uses: military  law enforcement  emergency search-and-rescue teams  business / commercial  conventions / expos  data acquisition admission.edhole.com
27 Challenges Facing Ad Hoc  Security  scalability  load balancing / etiquette between hosts  QoS  CPU/memory overhead  effect on devices’ battery life admission.edhole.com
28 Issues in Protocol Design  Must run in distributed environment  must provide loop-free routes  must be able to find multiple routes  must establish routes quickly  must minimize overhead in its communication / reaction to topology change admission.edhole.com
29 Some Implementation Choices  Flat vs. hierarchical architecture  proactive vs. reactive to topology changes  table-based, demand-driven, associativity-driven  topology change dissemination methods  when/how often to exchange topology info  assumptions about rate of change of topology and/or quality of connections admission.edhole.com
30 Some Ad Hoc Protocols  DARPA (1970s military packet radio) used with SURAN (SURvivable Adaptive Network; an early ad hoc networking testbed)  CGSR (hierarchical)  TORA (time-based; uses link reversal)  DSR  AODV admission.edhole.com
31 CGSR: Hierarchical Routing  All nodes send their data to cluster head nodes  heads act as second-tier, high-power network  +: simpler routing -: poor load balancing, not secure admission.edhole.com
In-Depth: AODV (Ad-hoc On-demand Distance Vector routing) 32  purely on-demand (no routes determined until needed)  each node contains routing table of next-hop information for how to get to every other node admission.edhole.com
33 AODV Path Discovery  Source node broadcasts a path discovery  message continues until it reaches destination, or node with path in table  sequence nums  discovery response sent back along reverse path admission.edhole.com
34 AODV Path/Connection Maintenance  Nodes ‘ping’ with hello messages to test links  timeouts assumed to be broken links  (only) recent active nodes notified of topology changes--propogated to neighbors admission.edhole.com
35 Contrast: DSR (Dynamic Source Routing)  resides in kernel IP layer (based on IPv6 format)  nodes contain tables of full paths to other nodes  messages: Route Request, Route Reply, Route Error, ACK  Send, Retransmit buffers admission.epdahsolsei.vcoem ACK
36 DSR Route Discovery  One-hop Route Request (ask immediate neighbors)  if that fails, broadcast request to whole network  Route Reply is sent by destination or node with path in cache admission.edhole.com
37 DSR Route/Connection Maintenance  Repeated failed requests to retransmit packets cause a Route Error message  on-demand; no pinging  all nodes in Route Error chain update their caches  source can again do admission.eRdohuotlee .Dcoismcovery
38 DSR Ack and Retransmit  Passive ACK - listen in promiscuous mode to see if neighboring nodes are forwarding  duplicate detection  adaptive retransmit - uses length of transmit queue to bump up retrans time during periods of network congestion  multi-level packet priority queue (IP TOS field) admission.edhole.com
39 How DSR Fits into Testbed admission.edhole.com
40 DSR vs. AODV DSR AODV rout ing table format full path next hop route checking passive acks ‘hello’ pings rate of propogat ion of fast slower topology changes abilit y to handle frequent topology change good fair CPU / memory usage high low scalabilit y poor excellent admission.edhole.com
41 More Protocol Comparisons admission.edhole.com

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Mba admission in india

  • 1. MBA Admission in India By: admission.edhole.com
  • 3. 3 Outline •Ad-Hoc Networking? •Why? •What? •How? •When? : Past, Present, Future admission.edhole.com
  • 4. 4 Scenario •The advent of cheap microprocessors and wireless technologies •Trend: ~1000 computer devices/person by 2010 admission.edhole.com
  • 5. 5 Use Cases admission.edhole.com
  • 6. Possibilities •Telephones (cellular, cordless, other) •Cordless multimedia (headsets, speakers, mic.) •Portable computers (Laptops, desktop, other) •Cordless computer peripherals (keyboard, mouse) •LAN – Local Area Network peripherals (printer, fax) •PDAs - Personal Digital Assistants (palm top/pilot) •Digital cameras 6 admission.edhole.com
  • 7. 7 Ad-…what? Ad-hoc network… …a LAN or other small network, …with wireless connections …devices are part of the network only for the duration of a communications session Or …while in close proximity to the network admission.edhole.com
  • 8. 8 Ad-hoc Networking Collection of wireless mobile nodes (devices) dynamically forming a temporary network without the use of any existing network infrastructure or centralized administration An ubiquitous type of computing often referred to as pervasive/invisible computing •Ubiquitous: Present, appearing, or found everywhere… •Pervasive: Spread through or into every part admiossf…ion.edhole.com
  • 9. Properties •Requires devices to cooperate autonomously •Without user intervention •Rapid self-organizing wireless network •Independent of infrastructure •Heterogeneous & adaptive admission.edhole.com 9
  • 10. 10 Why? Microprocessor embedding trend in: •cellular phones, car stereos, televisions, VCRs, watches, GPS (Global Positioning System) receivers, digital camera. •Ensembles of computational devices for: •environmental monitoring •personal area networks adm•gisesoiopnh.eydhsioclea.lc ommeasurement
  • 11. 11 How? Transmission Standards: 1. Piconet 2. HomeRF (Radio Frequency) 3. IEEE 802.11 Wireless LAN WG (Working Group) 4. Bluetooth SIG (Special Interest Group) • These above use radio waves from licence-exempt ISM (Industrial, Scientific and Medical) frequency band - around 2.4 GHz admission.edhole.com 5. IrDA (InfraRed Data Association) • which uses infrared instead of radio waves
  • 12. 12 Piconet • A general purpose, low-powered, ad-hoc network • It allows two devices near each other to inter-operate • These devices can be either mobile or fixed • The range is said admission.edhole.com to be reasonably short
  • 13. 13 HomeRF Uses Shared Wireless Access Protocol (SWAP) system • carries both voice and data traffic • inter-operate with the PSTN (Public Switched Telephone Network) and the Internet • the range covers typical home and yard admission.edhole.com
  • 14. IEEE 802.11 Wireless LAN The principles of Wireless Local Area Network (WLAN) are defined in IEEE 802.11 standard • It defines two different topologies: ad-hoc network and infrastructure network • This ad-hoc network is able to use only created wireless connection instead of fixed adminisfsrioans.terduhoclteu.croem 14
  • 15. 15 Bluetooth • The code name for an open specification for short-range wireless connectivity • Effortless, instant wireless connections between a wide range of communication devices in a small environment • The BT range restricts the environment to about 10 meters • Used in virtually any mobile device like that can have Bluetooth admission.edhole.com radios integrated into them
  • 16. IrDA • based on technology similar to the remote 16 control devices • high-speed short range, point-to-point cordless data transfer • in-room cordless peripherals to host-PC • maturity and standardization activities advantage over radio • line-of-sight admission.edhole.c roemquirement disadvantage
  • 17. 17 Wireless comparison admission.edhole.com
  • 18. Applications Some current deployments, research and prospects •Cybiko •Sensor Networks e.g. “Smart Dust” •Mobile Commerce (M-Commerce) - proposed admission.edhole.com 18
  • 19. 19 Cybiko •like a Palm Pilot, except with free games and and is designed for entertainment unlike palms which are really meant as organisers •wireless connectivity RF transmitter for text chat • when cybikos network together, they relay messages to other cybikos, which allows the range to be increased • up to 100 cybikos can be networked in this way, and 3000 cybikos can be online in one area at once before admission.the ISM edhole.RF band com gets full • it will have a range of approx. 1km outside, 500m inside
  • 20. 20 Sensor Nets – “Smart Dust ” I • thousands to millions of small sensors form self-organizing wireless networks • consists of nodes, small battery powered devices, that communicate with a more powerful base admission.station, edhole.which com in turn is connected to an outside network.
  • 21. 21 Sensor Nets – “Smart Dust ” II Metrics: CPU 8-bit, 4MHz Storage 8KB instruction flash 512 bytes RAM 512 bytes EEPROM Communication 916 MHz radio Bandwidth 10 kbps Operating TinyOS System OS code space 3500 bytes Available code space •Node to base sta4ti5o0n0 cbyotmesmunication, e.g. sensor readings •Base station to node communication, e.g. specific requests •admission.Base station edhole.to all nodes, com e.g. routing beacons, queries or reprogramming of the entire network
  • 22. M-Commerce • Mobile phones to extend the possibilities of commerce • make commerce platforms more important • electronic and mobile commerce transactions will be open for wide markets 22 admission.edhole.com
  • 23. Issues & Interests • What do you see as the next interesting things in mobile computing? • What potential do you see for wireless networks? • What do you see as the hardest things for us to address? Security for one! • If you could wish for one key piece of technology to come true (for mobility), what would it be? 23 admission.edhole.com
  • 24. Ad Hoc Networks and Their Protocols: admission.edhole.com
  • 25. Ad Hoc Networking A mode of loosely connected networking characterized by the following qualities:  lack of fixed infrastructure  peer-to-peer (all nodes act as routers)  multi-hop routing  frequent connection / topology changes 25 admission.edhole.com
  • 26. 26 Applications of Ad Hoc  Earliest uses: military  law enforcement  emergency search-and-rescue teams  business / commercial  conventions / expos  data acquisition admission.edhole.com
  • 27. 27 Challenges Facing Ad Hoc  Security  scalability  load balancing / etiquette between hosts  QoS  CPU/memory overhead  effect on devices’ battery life admission.edhole.com
  • 28. 28 Issues in Protocol Design  Must run in distributed environment  must provide loop-free routes  must be able to find multiple routes  must establish routes quickly  must minimize overhead in its communication / reaction to topology change admission.edhole.com
  • 29. 29 Some Implementation Choices  Flat vs. hierarchical architecture  proactive vs. reactive to topology changes  table-based, demand-driven, associativity-driven  topology change dissemination methods  when/how often to exchange topology info  assumptions about rate of change of topology and/or quality of connections admission.edhole.com
  • 30. 30 Some Ad Hoc Protocols  DARPA (1970s military packet radio) used with SURAN (SURvivable Adaptive Network; an early ad hoc networking testbed)  CGSR (hierarchical)  TORA (time-based; uses link reversal)  DSR  AODV admission.edhole.com
  • 31. 31 CGSR: Hierarchical Routing  All nodes send their data to cluster head nodes  heads act as second-tier, high-power network  +: simpler routing -: poor load balancing, not secure admission.edhole.com
  • 32. In-Depth: AODV (Ad-hoc On-demand Distance Vector routing) 32  purely on-demand (no routes determined until needed)  each node contains routing table of next-hop information for how to get to every other node admission.edhole.com
  • 33. 33 AODV Path Discovery  Source node broadcasts a path discovery  message continues until it reaches destination, or node with path in table  sequence nums  discovery response sent back along reverse path admission.edhole.com
  • 34. 34 AODV Path/Connection Maintenance  Nodes ‘ping’ with hello messages to test links  timeouts assumed to be broken links  (only) recent active nodes notified of topology changes--propogated to neighbors admission.edhole.com
  • 35. 35 Contrast: DSR (Dynamic Source Routing)  resides in kernel IP layer (based on IPv6 format)  nodes contain tables of full paths to other nodes  messages: Route Request, Route Reply, Route Error, ACK  Send, Retransmit buffers admission.epdahsolsei.vcoem ACK
  • 36. 36 DSR Route Discovery  One-hop Route Request (ask immediate neighbors)  if that fails, broadcast request to whole network  Route Reply is sent by destination or node with path in cache admission.edhole.com
  • 37. 37 DSR Route/Connection Maintenance  Repeated failed requests to retransmit packets cause a Route Error message  on-demand; no pinging  all nodes in Route Error chain update their caches  source can again do admission.eRdohuotlee .Dcoismcovery
  • 38. 38 DSR Ack and Retransmit  Passive ACK - listen in promiscuous mode to see if neighboring nodes are forwarding  duplicate detection  adaptive retransmit - uses length of transmit queue to bump up retrans time during periods of network congestion  multi-level packet priority queue (IP TOS field) admission.edhole.com
  • 39. 39 How DSR Fits into Testbed admission.edhole.com
  • 40. 40 DSR vs. AODV DSR AODV rout ing table format full path next hop route checking passive acks ‘hello’ pings rate of propogat ion of fast slower topology changes abilit y to handle frequent topology change good fair CPU / memory usage high low scalabilit y poor excellent admission.edhole.com
  • 41. 41 More Protocol Comparisons admission.edhole.com