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Bluetooth, Rfid , data link layer switching

Bluetooth, Rfid , data link layer switching. By Alisia Dunham & Chiana Grant . History of Bluetooth. 1994: L.M. Ericsson company had an idea of connecting mobile phones to other devices without cable

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Bluetooth, Rfid , data link layer switching

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  1. Bluetooth, Rfid, data link layer switching By Alisia Dunham & Chiana Grant

  2. History of Bluetooth • 1994: L.M. Ericsson company had an idea of connecting mobile phones to other devices without cable • 1998: SIG (Special Interest Group) is formed, including four other companies, such as IBM, Nokia, Toshiba, and Intel. • This development became known as Bluetooth, after HaraldBlaatand (Bluetooth) II • Viking who unified Denmark and Norway without cables (connections) • First version of Bluetooth, Version 1.0, was released in July of 1999

  3. Bluetooth Today • All consumer electronic devices use Bluetooth, such as mobile phones, laptops, and navigation units • Protocols are included with Bluetooth • Pairing: Allows the consumer electronic devices to find and connect each other and securely transfer data • Protocols have evolved over the decade • Bluetooth 2.0 (2004): higher data rates • Bluetooth 3.0 (2009): device pairing with 802.11 for high throughput data transfer • Bluetooth 4.0 (Dec. 2009) low power operation; saves battery use

  4. Bluetooth Architecture • Basic Unit: piconet • Master node and up to seven active slave nodes within a distance of 10 meters • Multiple piconets may exist in the same room and can be connected through a bridge node • Two or more piconets can be interconnected to form a scatternet • 205 parked nodes in the net. • Master node determines which device gets to communicate in which time slot • All communication is between master and slave

  5. Scatternet Example p.321

  6. Bluetooth Applications • Bluetooth SIG • Specifies particular apps to be supported and provides different protocols stacks for each one • 25 profiles • 6 audio and video • Hands-free telephony while driving car • Streaming stereo-quality audio and video • Digital camera to TV • Human-Interface device profile • Connects keyboards and mice to computers • Other profiles allow for a mobile phone to be used as a remote control.

  7. Bluetooth Protocol Stack • Does not follow any other model • Bottom Layer (Physical Radio Layer). • Link Control. • L2CAP (Logical Link Control Adaptation Protocol). • Top Layer.

  8. Bluetooth Protocol Architecture

  9. Bluetooth Radio Layer • Moves bits from master to slave, or vice versa • 10 meter range on a low-power system operating on a 2.4 GHz ISM band • Frequency hopping spread spectrum is used so other networks can coexist on the ISM band • 1600 hops/sec over slots with a dwell time of 625 picoseconds • Early revisions of bluetooth and 802.11 interfered enough to ruin each other’s transmissions.

  10. Radio Layer, cont. • Three forms of modulation are used to send bits on a channel • Basic Scheme: frequency shift typing to send a 1- bit symbol every microsecond, which equals 1 Mbps • Enhanced Rates: phase shift keying to send 2-3 bits per symbol, which equals to 2-3 Mbps • Only used in data portion of frames

  11. Bluetooth Link Layers • Turns raw bit stream into frames and defines some key formats • Simplest forms. • Frame length and other characteristics. • Link manager • Pairing Procedure: old vs. new • Upon Pairing Completion, the link manager sets up 1 of 2 links • SCO (Synchronous Connection Oriented). • ACL (Asynchronous ConnectionLess.

  12. Bluetooth Frame Structure • Access Code • 54-bit header • Frame sent in 2 rates • Basic rate: • Enhanced rate: • Inside the header are 6 sub-categories: • Address • Type • Flow • Acknowledgement • Sequence • Checksum

  13. Radio Frequency IdentificationR.F.I.D • Low end wireless devices that can be used to form computer networks • Technology that can be found in smartcards, implants for pets, passports, and library books to name a few • http://www.youtube.com/watch?v=yNPDgudPmXE&feature=youtu.be

  14. Electronic Product Code (EPC) • Form of RFID that is a replacement for barcodes that stores larger amount of information • Capable of being read over 10 M in distance • Ability to communicate over distance makes it relevant

  15. EPC 2nd Generation 2 key components: • Tags • Readers

  16. Key Components of EPC Tags small, inexpensive devices that have a 96-bit identifier and memory; memory is used to record location history; resembles a sticker and has an antenna printed on it; tiny dot in the middle = integrated circuit; “Class 1” is term used to define how tags gather power Readers are the intelligence in the system; has its own power source; in charge of determining when tags send and receive messages; main job is to discover the identifiers of nearby tags

  17. Key Components

  18. Physical Layer of EPC Generation 2 This layer defines how bits are sent between RFID readers and tags. To spread a strong signal, limit interference, and satisfy regulatory requirement the reader performs frequency hopping at least every 400 msec. ASK or Amplitude Shift Keying is used to encode bits The reader is always transmitting a signal, regardless of whether it is the reader or tag communicating. Backscatter is used a low-energy way for tags to create weak signals of their own.

  19. Identification Layer of EPC Generation 2 Readers need to receive a message from each tag that gives the identifier for the tag in order to inventory nearby tags. The reader tells tags the range of slots over which to randomize transmissions. However, tags randomly select slots in which to reply.

  20. Data Link Layer Switching • Bridges: devices that connect LANs to a larger, faster network • Commonly called switches • Operated in data link layer • Ability to handle IP packets

  21. Uses of Bridges • 3 reasons organizations use multiple LANs • Connection. • Cost. • Load Accommodation. • To make these benefits available, bridges must be completely transparent • Two algorithms make this possible • Backward learning • Spanning tree algorithm

  22. Learning Bridges Two lans joined by a bridge Lans with point-to-point cables, including one hub, are joined.

  23. Spanning Tree Bridge • Frame F0 is sent to B1 • B1 sends 2 copies on each link to B2 • B2 sends copies of F1 and F2 to all other ports • F3 and F4 are sent back to B1, and the cycle continues

  24. Repeaters, Hubs, Bridges, Switches, Routers, and Gateways Operates at different layers Physical = repeater, hub Data link = bridge, switch Network = router Transport = transport gateway Application = application gateway

  25. Repeaters, Hubs, Bridges, Switches, Routers, and Gateways Repeaters do not understand frames, packets, or headers; only understand symbols that encode bits as volts. Hubs are physical layer devices that do not examine the link layer addresses or use them in any way Modern bridge has multiple ports, usually enough for 4 to 48 input lines of a specific type. Each port is isolated to be its own collision domain

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