Tema02-Estándar802.11-Interface de red

8/13/2019 Tema02-Estndar802.11-Interface de red

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Teora de Redes LANInalmbricas

Curso : Configuracin de Equipos

Equipo de Profesores del Curso


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UNIDAD 1

Al trmino de la unidad, el alumno disea una

red LAN inalmbrica siguiendo las recomendacionesde las normas 802.11x y las mejores prcticas de diseo.

Teora de Redes LAN Inalmbricas


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Teora de Redes LANInalmbricas

Curso : Configuracin de Equipos

Equipo de Profesores del Curso


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Wireless Networks

Wireless Networks come in many forms, cover variousdistances, and provide a range of low to highbandwidth depending on the type installed.


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Basic Wireless Devices:1. Access Points

Like half duplex hubs APs function as a bridge to the wired

network. Aps connection to the wired network is

called DS (Distribution System), and it alsokeep MAC address information within802.11 frames.

These frames are capable of holding asmany as 4 MAC address.


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An AP also keep an association table. In Cisco World, 2 types of APs:

Autonomous Light-weight Wireless LAN Controller

In this scenario the Aps are functioning asantennas and all information is sent back to theWLC.

An AP also keep an association table


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In Cisco World, 2 types of APs:

a. Autonomous

b. Light-weight Wireless LAN Controller

In this scenario the Aps are functioning as antennas and allinformation is sent back to the WLC.


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2. Wireless Network Interface Card

A Wireless NIC does the same job as atraditional NIC, only instead of having asocket/port to plug a cable into, the wireless

NIC has a radio antenna.


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3. Antennas

Two broad classes of antennas a. Omni-Directional: Point-to-multipoint


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b. Directional : Point-to-point


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Yagi antennas usually provides greaterrange than omni antennas of equivalentgain. Why?

Yagis focus all their power in one direction


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Wireless Topologies

IBSS BSS ESS Workgroup bridges Repeater Aps

Bridging Mesh


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IBSS : Independent Basic ServiceSet (Ad-Hoc) No need for an AP One computer may be able to share the

Internet connection with the rest of them inyour group.

Also refered as Peer-to-peer


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Basic Service Set (BSS)

It is the area or cell, defined by the wirelesssignal served by the AP.

It can also calles BSA(Basic Service Area)


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Infraestructure Basic Service Set

In this case wireless NICs only communicatewith an AP instead of directly with each other.

The AP is connected to the wired network , this

connection is called DS (Distribution System) Basic standalone Aps do not communicate witheach other via the wireless network, onlytrough the DS.

SSID defines the BSS, its a 32 characteridentifier.

An Aps may have multiple identifier.


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Service Set Identifier (SSID)

It can be up to 32 characters long. It can be broadcasted or hidden. The AP associates a MAC address to this

SSID. It can be the MAC address for the radio

interface itself, or it can be derived from theMAC address of the radio interface if multipleSSIDs are used (Virtual MAC address)

In this case, it is called MBSSID (Multiple BasicService Set Identifier )


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The reason for create Multiple SSIDs onyour AP is so that you can set differentlevels of security.


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ESS: Extended Service Set ID

If you set all your APs to the same SSID,mobile wireless clients can roam aroundfreely within the same network.

All APs must overlap by at least 10 percentof their signal.

Be sure the channels on each AP are setdifferently.


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ESS: Extended Service Set ID


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Workgroup Bridge

Used if you have a bunch of hosts that needto connect to the wireless network but theydont have wireless cards or wireless

capability.

aWGB: AutonomousWGB


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Cisco support two types of WGBs:

1. Autonomous WGB: aWGB2. Universal WGB : uWGB


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Autonomous WGB: aWGB Its a propietary version and appears to a

Cisco AP as a single normal client. Universal WGB : uWGB Its a nonpropietary version and appears to a

Cisco AP as a nonstandard client.


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Repeaters

To extend the coverage of an AP: Increase the gain of a directional antenna Add another AP in the area Add a repeater For every repeater installed you lose about

half of your troughput.

It uses its antenna to receive the signalfrom an AP, and repeats the signal forremote clients.


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BW1:11 Mbps BW2:5.5 Mb


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Bridging

Bridges are used to connect 2 or more wiredLANs, usually located within separatebuildings, to create one big LAN.

They operate at MAC address layer. Theyhave no routing capabilities.

Type of bridges:1. Root Bridge Parent bridge2. NonRoot bridge Child bridge


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Typical bridge scenariosNon ROOT Devices1. Non-root bridges2. Workgroup bridges3. Repeater Access Points4. Wireless clients

ROOT Devices1. Access Point2. Bridges

1. Non-Root :communicate to Rootdevices

2. Root devices: cannotcommunicate to other Root

devices3. Non Root Cannot communicate


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If you have a nonroot bridge set up as arepeater AP with two radios, the device mustbe configured as a nonroot device.


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MESH Networks

Its a network topology in which devices areconnected with many redundant connectionsbetween hosts nodes.

To manage many APs it is needed aprotocol, it is Lightweigh Access PointProtocol (LWAPP).


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Basic Access PointConfiguration


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Rick [email protected] 30

LED indicators

The LED lights on an access point convey status information. When the access point is powering on, all three LEDs normally blink.

After bootup, the colors of the LEDs represent the following: Green LEDs indicate normal activity. Amber LEDs indicate errors or warnings. Red LEDs mean the unit is not operating correctly or is being

upgraded.

1100 AP 1200 AP


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Reset the AP (Power On)

When beginning a lab, to make sure the AP has the default settings,you will reset the AP.

Follow these steps to reset the access point to factory default settingsusing the access point MODE button:

Step 1 Disconnect power (the power jack for external power or theEthernet cable for in-line power) from the access point.

Step 2 Press and hold the MODE button while power to the accesspoint is reconnected.

Step 3 Hold the MODE button until the Status LED turns amber (approximately 1 to 2 seconds), and release the button. All access

point settings return to factory defaults.

1100 AP 1200 AP


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Reset the AP (Power On)

The Reset button on the 340 and 350 AP is in a small hole on the backpanel of the base station.

To activate the Reset button, insert a straightened paper clip into thesmall hole and press. Remove the paper clip. The Status LED blinks amber to show the base station has the

default parameter values.

350 AP


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Cisco AP Factory Default Settings

255.255.255.0 (/24)


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Connecting to the AP (Configuration)

Wired Wireless: Requires Association


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Connecting to the AP (Configuration)

Console : 9600-8-N-1-None Ethernet or Wireless adapter :

Unless routing, be sure it is on the IP addresses are same subnet. Usually, you can only use one or the other.

Be sure disable or physically disconnect the one that is not in use.

) ) ) ) )

10.0.0.101/24

10.0.0.1/2410.0.0.102/24


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Connecting to the AP (Console)

There are two different types of CLI: IOS CLI VxMenu

ConsoleSerialRollover Cable

VxMenuIOS CLI


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Connecting to the AP (Telnet)

Requires a network connection either Ethernet or Wireless

AP Defaults IP Address = 10.0.0.1/24 Username and Password =

Cisco (C not c) This password is the

privilege password, not theWEP password.

Cisco


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Connecting to the AP (Browser)

Wired Wireless: Requires AssociationPreferred Method!


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Connecting to the AP (Wireless)

Wireless adapter : If configuring using the wireless adapter, you must first associate

with the AP. Make sure the settings on the ACU match the AP. Cisco 1100 and 1200 Aps have the following defaults:

IP Address = 10.0.0.1/24 SSID = tsunami

Password = Cisco (C not c)

SSID = tsunami

SSID = tsunami


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Connecting to the AP (Wired)

Wired Ethernet : No association necessary

Make sure the IP Address on the Ethernet interface is on the samesubnet as the AP.

AP Defaults IP Address = 10.0.0.1/24 Password = Cisco (C not c)

Preferred Method!

SSID = tsunami

SSID = tsunami


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Connecting to the AP (Wired)

Wired Ethernet : We will use the browser via wired method to initially configure

APs during labs so we do not configure the wrong AP via wireless.

Preferred Method!

SSID = tsunami

SSID = tsunami


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Rick [email protected]

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Configuring IP Addresses

Configuring the IP address on Hosts Ethernet interface

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Access the AP via the Browser

Cisco

10.0.0.1


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Two things to change

At the beginning of each lab, after you have connected via the wired Ethernet interface, you will change the IP Address and SSID on the AP, so the otherLab Station does not accidentally configure yours.

You will also need to change your Hosts IP address .

Ex: 192.168.1.1/24 Ex: 192.168.1.2/24SSID: AP-Pod1

HostnameNot SSID

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Express Setup

Always configure andtest the basics first,before configuringauthentication andother options.

You will most likelylose connection onceyou change the IPaddress/mask.

10.0.0.1

255.255.255.224

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Tema02-Estándar802.11-Interface de red