working of lan

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PRESENTATION

WORLD

LAN (Local Area Network)

by: Vishwa

LAN (Local Area Networks) A LAN is a computer network that covers a small area (home, office,

building, campus)o a few kilometers

LANs have higher data rates (10Mbps to 10Gbps) as compared to WANs

LANs (usually) do not involve leased lines; cabling and equipments belong to the LAN owner.

A LAN consists ofo Shared transmission medium

• now so valid today due to switched LANso regulations for orderly access to the mediumo set of hardware and software for the interfacing devices

LAN usually broadcast their message to all hosts on that LAN.

WORKING OF LAN

This hosts shares a single transmission media. This broadcast network can be a static or dynamic

method. In this static method each host is given a fixed time

slides to send the information. This is the most popular method used.

In the dynamic method a host can send a frame any time.

If the two hosts send a frame at the same time the two frames could collide with each other.

Dynamic method can be further sub-divided in 2 categories:

1. Centralizeda. Carrier Sensingb. Token Passing

2. Decentralized: Protocols are used to implement media access control.

LAN Protocol Architecture Corresponds to lower two layers of OSI model

o But mostly LANs do not follow OSI model

Current LANs are most likely to be based on Ethernet protocols developed by IEEE 802 committee

IEEE 802 reference modelo Logical link control (LLC)o Media access control (MAC)o Physical

LAN PROTOCOLS IN CONTEXT

LAN Interconnection

Traditional LAN interconnection devices Repeater – it operates at OSI layer 1 and transmits data bits over a physical

medium. Bridge – it operates at OSI layer 2 and is commonly used to connect similar

LAN segments. Switch – it operates at OSI layer 2 or layer 3 and is used to interconnect

multiple similar or dissimilar LANs. Router – it operates at OSI layer 3. A router is used to interconnect individual

networks whose sizes vary from very small to very large. Routers may be categorized into backbone router (or core router), border router and access router depending on their role in the network.

TOPOLOGIES• Star

• Bus

• Ring

LAN Architecture

Transmission medium Layout Medium access control

LAN TOPOLOGIES

Advantages

Long Distances Possible10 Base-5 allows distances up to 500 meters (1650 feet). Thismakes it very useful as a "backbone" technology for wiringtogether multiple locations within a building without the use ofrepeaters Noise ImmunitySince 10 Base-5 uses a very heavily shielded cable, it can be usedin electrically noisy environments which can cause other networktypes to fail. Conceptually SimpleSince all devices on a 10 Base-5 network are simply chainedtogether on a common coaxial cable, it is a simple matter to planthe routing of the cable

Disadvantages

Inflexible10 Base-5 networks do not lend themselves well to installationswhere the setup of the network will change much after the initialinstallation. It can be very difficult to add or move a node once itis connected to the coaxial cable. Fault IntolerantSince 10 Base-5 uses a common physical cable to interconnect allthe nodes, the failure of any part of the coaxial cable or any nodehas the ability to cause the collapse of the entire network.

Bluetooth Technology

by: PANDU

Created by Matt Romita and Mohammed Hasham for BCS 312 and used in BCS 555

Bluetooth BirthBluetooth BirthThe Name –Bluetooth?

The name is attributed to Harald Bluetooth was king of Denmark around the turn of the last millennium.


What Is Bluetooth?

• Designed to be used to connect both mobile devices and peripherals that currently require a wire.

• Short range wireless radio technology. - operate range of 100 meters.

• “USB without wires”


Who Started Bluetooth?

• Bluetooth Special Interest Group (SIG) -5 founding members -Ericsson, Nokia, IBM, Intel & Toshiba

• Promoter’s Group - 3COM, Lucent, Microsoft, Motorola

• Now over 1900 members

Ericsson Mobile Communication


How Does It Work?

• Bluetooth is a standard for tiny, radio frequency chips that can be plugged into your devices

• These chips were designed to take all of the information that your wires normally send, and transmit it at a special

frequency to a receiver Bluetooth chip.


Bluetooth @ Home

NO WIRESComputer

Digital Camera

Scanner

InkjetPrinter

xDSLAccess Point

Home Audio System PDACell Phone

Cordless PhoneBase Station

MP3Player


Bluetooth Products 1

• Bluetooth-enabled PC Card



• Bluetooth-enabled PDA



• Bluetooth-enabled Cell Phone



• Bluetooth-enabled Head Set


Advantages (+)

• Wireless (No Cables)

• No Setup Needed

• Low Power Consumption (1 Milliwat)

• Industry Wide Support


Disadvantages (-)

• Short range (10 meters)

• Small throughput rates

- Data Rate 1.0 Mbps

• Mostly for personal use (PANs)

• Fairly Expensive

WIRELESS LANWIRELESS LAN

WIRLESS LOCAL AREA WIRLESS LOCAL AREA NETWORKNETWORK

Wireless LANsWireless LANs


IntroductionIntroduction Wireless TechnologyWireless Technology Wireless LAN Wireless LAN ConfigurationConfiguration Differences between wired LAN vs Differences between wired LAN vs

wireless LANwireless LAN

INTRODUCTIONINTRODUCTION Data communications system Data communications system Alternates wired LANAlternates wired LAN Transmits and receives data over the air Transmits and receives data over the air Minimize the need for wired connectionsMinimize the need for wired connections Become more popular in general-purpose Become more popular in general-purpose

alternative of business customers.alternative of business customers. Benefited several industries in Benefited several industries in

productivity and mobilityproductivity and mobility

WHY WIRELESS?WHY WIRELESS?

Advantages:Advantages:

MOBILITYMOBILITY INSTALLATIONINSTALLATION COSTCOST SCALABILITYSCALABILITY

MOBILITYMOBILITY

Real-time information access from Real-time information access from anywhere at any timeanywhere at any time

Increases productivity and Increases productivity and flexibilityflexibility

HOW IT WORKSHOW IT WORKS

Use electromagnetic airwaves to Use electromagnetic airwaves to communicate informationcommunicate information

Data imposed on radio carrier (radio Data imposed on radio carrier (radio wave)wave)

RF electromagnetic wave can RF electromagnetic wave can easily pass through ordinary wall, easily pass through ordinary wall, it needs to implement with heavy it needs to implement with heavy concrete or metal screening.concrete or metal screening.

WIRELESS TECHNOLOGYWIRELESS TECHNOLOGY

Satellite-Based System Satellite-Based System – Geosynchronous Earth Orbiting (GEO)Geosynchronous Earth Orbiting (GEO)– Low Earth Orbiting (LEO)Low Earth Orbiting (LEO)

Land-Based Network Access Land-Based Network Access SystemSystem– Wireless WAN Wireless WAN – Wireless LANWireless LAN

WIRELESS WANWIRELESS WAN

Provide nationwide or citywide Provide nationwide or citywide coveragecoverage

Example: Ricochet Micro-CellExample: Ricochet Micro-Cell


Wireless LAN TopologyWireless LAN Topology– 2 main components2 main components

Access PointsAccess Points AdaptersAdapters

– RoamingRoaming Wireless LAN TechnologyWireless LAN Technology

– TypesTypes– StandardStandard– ConfigurationConfiguration

ACCESS POINTSACCESS POINTS

Connects to the wired network Connects to the wired network single access point can support a single access point can support a

small group of users within a range small group of users within a range of several hundred feetof several hundred feet

Wireless Clients Connected to LAN via Access Point

WIRELESS LAN WIRELESS LAN TECHNOLOGYTECHNOLOGY

Narrowband TechnologyNarrowband Technology Spread Spectrum TechnologySpread Spectrum Technology

– Frequency-Hopping Spread Spectrum Frequency-Hopping Spread Spectrum TechnologyTechnology

– Direct-Sequence Spread Spectrum Direct-Sequence Spread Spectrum TechnologyTechnology

Infrared TechnologyInfrared Technology

INFRARED (IR) INFRARED (IR) TECHNOLOGYTECHNOLOGY

Little used in commercial wireless LANsLittle used in commercial wireless LANs Use very high frequenciesUse very high frequencies Inexpensive, but provide very limited Inexpensive, but provide very limited

range (3ft)range (3ft) Typically used for personal area Typically used for personal area

networksnetworks Used only to implement fixed Used only to implement fixed

subnetworkssubnetworks

CONFIGURATIONCONFIGURATION

Peer-to-peer networkPeer-to-peer network Client and Access pointClient and Access point Multiple access points and roamingMultiple access points and roaming Using an extension pointUsing an extension point Using directional antennas Using directional antennas

•

Star Topology

by:CH.Mahesh

Star Topology:Star Topology:

• The star network configuration is the most popular physical topology

• In a star configuration, all computers or stations are wired directly to a central location:– Concentrator (a.k.a. hub)– Multistation Access Unit (MAU)

• A data signal from any station goes directly to this central device, which transmits the signal according to the established network access method for the type of network

Physical Topologies:Physical Topologies:StarStar

Figure-2:Star topology

Star topology advantages:Star topology advantages:

– A break in one cable does not affect all other stations as it does in bus technologies

– Problems are easier to locate because symptoms often point to one station

– The second-easiest topology to design and install– Does not require manual termination

• Instead the media is terminated in the station at the transceiver on the NIC and in the hub or MAU

Star topology disadvantages:Star topology disadvantages:

– Hubs, which are required for a star topology, are more expensive than bus connectors

– A failure at the hub can affect the entire configuration and all connected stations

– Uses more cable than bus topologies

working of lan

Technology

star topology

coaxial cable

dynamic method

matt romita

mohammed hasham

osi layer

wireless

bluetooth