1 © 2004, Cisco Systems, Inc. All rights reserved. Wireless Local Area Networks (WLANs)

  • Published on
    16-Jan-2016

  • View
    216

  • Download
    0

Transcript

CCNA 1 Chapter 2 Networking Fundamentals

Why are the using of Radio Frequencies (RFs) more than Infrared Light (IR)?the using of Radio Frequencies (RFs) more than Infrared Light (IR) because of: 1- Higher Bandwidth2- Wider coverage WLAN use 2.4 and 5 GHZ frequency band3- Provide freedom and flexibility within building and between buildings### 2004, Cisco Systems, Inc. All rights reserved.4What is a wireless LAN?Instead of using cables, WLANs use: Infrared light (IR)802.11 does include an IR specificationlimitations, easily blocked. Radio frequencies (RFs) Can penetrate most office obstructions

802.11b Access PointBar code scanner

PDATelephone### 2004, Cisco Systems, Inc. All rights reserved.3Wireless Network components The wireless network is less complex than wired networksThere are two basic components in wireless network1- Wireless Access Point (WAP) 2- a wireless NIC

### 2004, Cisco Systems, Inc. All rights reserved.5Wireless Network componentsFirst : Wireless Access Point 1- Is a central component (like a hub or switch)2- Its function is to operate as a hub for wireless devices3- It has at least one antenna4- It has a port to connect the wireless AP to a wired network

### 2004, Cisco Systems, Inc. All rights reserved.6Wireless Network components Second : Wireless NICWireless NIC does the same job as traditional NIC ,but instead of having a socket to plug some cable into, the wireless NIC will have a radio antenna.Wireless antenna act as transmitter and receiver.

There are two classes of antennas:1- OMNI directional antennas (point-to-multipoint):EX: FM antenna2- Directional (Yagi (or) point-to- point):Yagi is limited in coverage areaMost of WAP use OMNI antenna### 2004, Cisco Systems, Inc. All rights reserved.7Why Wireless?

### 2004, Cisco Systems, Inc. All rights reserved.8Wireless LAN standards

Infrared networking Is a type of wireless networkingPoint-to-point communication , short distance Infrared wireless use IrDA standard ( standard for point-to-point)Data transmission rate (16mbps)updated to (100 mbps)Max range = 1 meter

Bluetooth networkingWireless standard Max throughput = 1 mbps

### 2004, Cisco Systems, Inc. All rights reserved.9Wireless LAN standards802.11 Is a set of standards that govern wireless network transmission methods.Provide authentication and authorization of LAN nodes.Developed by IEEE LAN/MAN standard in 1997.Frequency range = 2.4 GHZSupport Max network bandwidth (Data rate)= 2 MbpsIn noisy environments fall back to 1 Mbps

### 2004, Cisco Systems, Inc. All rights reserved.10802.11a802.11 is too slow for most applicationMax data rate (B.W)= 54 MbpsRadio frequency range= 5 GHZMax range (indoor) = 76 mMax range (outdoor) = 305 mAdvantages1- Fast Max speed2- Regulated frequency prevent interference from other devicesDisadvantages1- Highest cost2- shorter range signal that more easily obstructed### 2004, Cisco Systems, Inc. All rights reserved.11802.11bData rate (B.W)= 11 MbpsRadio frequency range= 2.4 GHZ Max range (indoor) = 91 mMax range (outdoor) = 457 mAdvantages1- Lowest cost2- Signal range is good and not easily obstructed3- It is easy to installDisadvantages1- Slowest Max speed2- Home application may interfere on the unregulated frequency band### 2004, Cisco Systems, Inc. All rights reserved.12802.11gData rate (B.W)= 54 MbpsRadio frequency range= 2.4 GHZMax range (indoor) = 91 mMax range (outdoor) = 457 mAdvantages1- Fast Max speed2- Signal range is good and not easily obstructedDisadvantages1- cost more than 802.11b2- application may interfere on the unregulated frequency band### 2004, Cisco Systems, Inc. All rights reserved.13More about WLANModes of Operation Ad-Hoc mode (Independent BasicService Set - IBSS) Infrastructure mode (Basic ServiceSet - BSS)### 2004, Cisco Systems, Inc. All rights reserved.14Installation type Ad-Hoc modeIn this mode , the wireless NICs or other devices can communicate directly without the need for a WAPTo setup a basic ad-hoc wireless network , all you need are two wireless NIC and two computers, during the installation of the software you will be asked at some point if you want to setup the NIC in ad-hoc mode or infrastructure mode, choose ad-hoc mode the bring the computers within range (90-100) meter , then you will be able to connect to each other

Client AClient B### 2004, Cisco Systems, Inc. All rights reserved.15Installation type Infrasructure modeIn this mode , NICs will only communicate with an access point (instead of each other as in ad-hoc mode).The access point will facilitate communication between the wireless nodes as well as communication with a wired network (if present).

Client AAccess pointClient B### 2004, Cisco Systems, Inc. All rights reserved.16

Recommended

View more >