Transcript Dccn - WordPress.com

Topic:
Wireless LAN, IEEE 802.11,Bluetooth, Virtual Circuit
Group Members:
Ankita Pattanaik
Vivash Kr. Pandey
Rakesh Kr. Jena
Soumya Shree Rath
Vivek Kumar
Wireless LAN
 A wireless local area network (WLAN) links two or more devices.
 Typically based on Spread-spectrum or ODFM radio.
 WLANs are based on IEEE 802.11 standards, marketed under the
Wi-Fi brand name.
 An embedded Router Board 112 with U.FL-RSMA pigtail and
R52miniPCI Wifi card widely used by Wireless internet service providers
(WISPs).
 It uses an UDP Protocol .
 Norman Abramson, a professor at the University of Hawaii, developed the
world’s first wireless computer communication network, ALOHAnet, using
low-cost ham-like radios.
Generation of Wireless LAN
 first generation wireless data modems:
developed in the early 1980's by amateur communication groups.
added a voice band data communication modem, with data
rates below 9600 bps, such as a walkie talkie.
 Second generation wireless data modems:
non-military use of the spread spectrum technology. These modems
provided data rates on the order of hundreds of Kbps.
 Third generation wireless data modems:
compatibility with the existing LANs with data rates on the order of
Mbps. Currently, several companies are developing the third
generation products with data rates above 1 Mbps and a couple of
products have already been announced.
Examples of Wireless LAN
 Wifi:
 ”wireless fidelity” and is meant to be used generically when referring of
any type of 802.11 network.
 Popular technology that allows an electronic device to exchange
data wirelessly (using radio waves) over a computer network,
including high-speed Internet connections.
 Wi-Fi is designed as a wireless extension to local area networks (LAN)
for indoor use with a range up to 100m.
 It uses a standard protocol of 802.11 a/b/g/n.
 It uses a frequency of 2.5 Ghz to 5.8 Ghz for data transmision and a
data rate of 54mbps.
Examples of Wireless LAN
 WiMax:
 “Worldwide Interoperability for Microwave Access”
 WiMAX was originally designed to provide fixed BWA in metropolitan
area networks (MAN) with a range of up to 50 km.
 Wimax network operate at 60 MHz frequency and data rate is 1 Gbit/s
for fixed stations
 The original IEEE 802.16 standard (now called "Fixed WiMAX") was
published in 2001.
IEEE 802.11 protocol
 IEEE 802.11 is a set of standards for implementing wireless local area
network (WLAN) computer communication in the 2.4, 3.6 and 5 GHz
frequency bands.
 802.11 technology has its origins in a 1985 ruling by the U.S. Federal
Communications Commission that released the ISM band for unlicensed
use.
 In 1991 NCR Corporation /AT&T (now Alcatel-Lucent and LSI
Corporation) invented 802.11.
 Vic Hayes , who held the chair of IEEE 802.11 for 10 years and has been
called the "father of Wi-Fi" was involved in designing the initial 802.11b
and 802.11a standards within the IEEE .
 The original version of the standard IEEE 802.11 was released in 1997 and
updated itself in 1999, but is today obsolete
 It specified two net bit rates of 1 or 2 megabits per second (Mbit/s).
Types of IEEE 802.11 protocol
4 Types of IEEE 802.11 protocol:
802.11 a
802.11 b
802.11 g
802.11 n
IEEE 802.11 a protocol

IEEE 802.11a-1999

The 802.11a standard uses the same data link layer
protocol and frame format as the original standard.

It operates in the 5 GHz frequency with net data rate of
54 Mbit/s .
802.11a signals are absorbed more readily by walls and
other solid objects in their path due to their smaller
wavelength .
Higher hardware equipment costs.


Pros of 802.11a - fast maximum speed; regulated frequencies prevent signal
interference from other devices
Cons of 802.11a - highest cost; shorter range signal that is more easily
obstructed
IEEE 802.11 b protocol

IEEE 802.11b-1999

802.11b has a maximum data rate of 11 Mbit/s

802.11b products appeared on the market in early 2000

802.11b devices suffer interference from other products
operating in the 2.4 GHz band.
Devices include are microwave ovens, Bluetooth devices,
cordless telephones and some amateur radio equipment.

Pros of 802.11b - lowest cost; signal range is good and not easily obstructed
Cons of 802.11b - slowest maximum speed; home appliances may interfere on
the unregulated frequency band
IEEE 802.11 g protocol





IEEE 802.11g-2003
In June 2003, a third modulation standard was rectified:
802.11g.
It operates at a maximum physical layer bit rate of 54
Mbit/s
most dual-band 802.11a/b products became dualband/tri-mode, supporting a and b/g in a single
mobile adapter card or access point.
uses the 2.4 Ghz frequency for greater range.
Pros of 802.11g - fast maximum speed; signal range is good and not easily
obstructed
Cons of 802.11g - costs more than 802.11b; appliances may interfere on the
unregulated signal frequency
IEEE 802.11 n protocol

IEEE 802.11n-2009

Uses multiple-input multiple-output antennas (MIMO).

Operates on both the 2.4 GHz and the lesser used 5 GHz
bands.

It operates at a maximum net data rate from 54 Mbit/s
to 600 Mbit/s.
Pros of 802.11n - fastest maximum speed and best signal range; more resistant
to signal interference from outside sources
Cons of 802.11n - standard is not yet finalized; costs more than 802.11g; the use
of multiple signals may greatly interfere with nearby 802.11b/g based networks
Bluetooth

Bluetooth(R) wireless technology is a open wireless
technology standard for exchanging data over short
distances (using short-wavelength radio transmissions.

Bluetooth uses a radio technology called frequencyhopping spread spectrum.

Creating personal area networks (PANs) with high levels
of security

Created by telecoms vendor Ericsson in 1994,it was
originally conceived as a wireless alternative toRS-232
data cables.
Bluetooth

Bluetooth is a packet-based protocol with a master-slave structure. One
master may communicate with up to 7 slaves .

Bluetooth is managed by the Bluetooth Special Interest Group,
(SIG)which has more than 16,000 member companies in the areas of
telecommunication, computing, networking, and consumer
electronics.

Bluetooth provides a secure way to connect and exchange
information between devices such as faxes, mobile
phones, telephones, laptops, personal computers, printers, Global
Positioning System(GPS) receivers, digital cameras, and video game
consoles.

Protocols used: PPP,TCP/IP/UDP, OBEX ,WAE/WAP
Versions of Bluetooth

Bluetooth v1.0 and v1.0B:
Interoperable connection problems ,mandatory
requirement of device address.

Bluetooth v1.1:

Bluetooth v1.2: IEEE Standard 802.15.1-2005 Compatible with v1.1,faster
IEEE Standard 802.15.1-2002 , Many errors found in the v1.0B
specifications were fixed , Received Signal Strength Indicator (RSSI ).
connection & discovery, transmission data rate upto 721kbps.

Bluetooth v2.0 + EDR: Compatible with previous version, Enhanced data rate
with 3mbps

Bluetooth v2.1 + EDR: Compatible with previous version,uses Secure Simple
Passing(SSP) technique

Bluetooth v3.0 + HS: Uses 802.11 link, data transfer of high speeds of up to 24
Mbit/s

Bluetooth v4.0: Includes Classic Bluetooth, Bluetooth high
speed and Bluetooth low energy protocols.
Virtual Circuit
A virtual circuit is a circuit or path between points in a network
that appears to be a discrete, physical path but is actually a
managed pool of circuit resources from which specific circuits
are allocated as needed to meet traffic requirements.
A permanent virtual circuit (PVC) is a virtual circuit that is
permanently available to the user just as though it were a
dedicated or leased line continuously reserved for that user.
 PVCs are an important feature of frame relay networks .
 A switched virtual circuit (SVC) is a virtual circuit in which a
connection session is set up for a user only for the duration of a
connection.
Virtual Circuit
 virtual circuit (VC), synonymous with virtual connection and virtual channel
, is a connection oriented communication service that is delivered by means
of packet mode communication.
 After a connection or virtual circuit is established between two nodes or
application processes, a bit stream or byte stream may be delivered between
the nodes
 A virtual circuit protocol allows higher level protocols to avoid dealing with
the division of data into segments, packets, or frames
Virtual Circuit
 Examples of protocols that provide virtual circuit
Transmission Control Protocol (TCP), where a reliable virtual circuit is established on top of the underlying
unreliable and connectionless IP protocol.
Stream Control Transmission Protocol (SCTP), where a virtual circuit is established on top of either the IP
protocol or the UDP protocol.
 Examples of network layer and datalink layer virtual circuit protocols, where data always is
delivered over the same path:
X.25 , where the VC is identified by a virtual channel identifier (VCI). X.25 provides reliable node-to-node
communication and guaranty
Frame relay, where the VC is identified by a VCI. Frame relay is unreliable, but may provide guaranteed QoS.
Asynchronous Transfer Mode (ATM), where the circuit is identified by a virtual path identifier (VPI) and virtual
channel identifier (VCI) pair. ATM is unreliable, but may provide guaranteed QoS.
General Packet Radio Service (GPRS)
Multiprotocol label switching(MPLS), which can be used for IP over virtual circuits. Each circuit is identified by a
label. MPLS is unreliable, but provides eight different QoS classes.
Refrence
 http://en.wikipedia.org/wiki/Wireless_LAN
 http://www.usr.com/download/whitepapers/wireless-wp.pdf
 http://en.wikipedia.org/.../Institute_of_Electrical_and_Electroni
cs_Enginee
 http://en.wikipedia.org/wiki/IEEE_802.11
 http://www.compnetworking.about.com › ... › Wi-Fi Wireless
 http://en.wikipedia.org/wiki/Bluetooth
 http://en.wikipedia.org/wiki/Virtual_circuit
 http://www.webopedia.com/TERM/V/virtual_circuit.html