by alisia dunham & chiana grant. 1994: l.m. ericsson company had an idea of connecting mobile...
TRANSCRIPT
BLUETOOTH, RFID, DATA LINK LAYER
SWITCHINGBy Alisia Dunham & Chiana Grant
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 Harald Blaatand (Bluetooth) II Viking who unified Denmark and Norway without
cables (connections) First version of Bluetooth, Version 1.0, was
released in July of 1999
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
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
Scatternet Examplep.321
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.
Bluetooth Protocol Stack
Does not follow any other model Bottom Layer (Physical Radio Layer). Link Control. L2CAP (Logical Link Control Adaptation
Protocol). Top Layer.
Bluetooth Protocol Architecture
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.
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
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.
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
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
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
EPC 2nd Generation
2 key components: I. Tags II. Readers
Key Components of EPC
Tagssmall, 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
Key Components
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 bitsThe 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.
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.
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
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
Learning Bridges
TWO LANS JOINED BY A BRIDGELANS WITH POINT-TO-POINT CABLES, INCLUDING ONE HUB, ARE JOINED.
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
Repeaters, Hubs, Bridges, Switches, Routers, and Gateways
Operates at different layersPhysical = repeater, hubData link = bridge, switchNetwork = routerTransport = transport gatewayApplication = application gateway
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 wayModern 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