Ch 4 Wireless Networking

Technology behind *802.11* is branded as

"Wi-Fi"

Network access in 802.11 used

*Carrier Sense Multiple Access/ Collision Avoidance (CSMA/CA)*

Advantages of wireless networks:

*Cost-effective*- no running cables saves time and expense *User mobility* *Convenience* *Easily expand the network*

What kind of network is the ad-hoc network?

*Local Area Network (LAN)* that is built spontaneously as devices connect.

RFID consists of two things:

*RFID tag (RF transponder)* *A reader*

*Wi-Fi alliance* *officially retired WEP* in

2004

"How does the access point know that the wireless data packet is being sent from a client in the wireless LAN?"

802.11 wireless LAN devices use an SSID to identify what wireless data traffic is allowed to connect the network. The SSID is the wireless service set identifier, basically a password that enables the client to joint he wireless network. The access point uses the SSID to determine whether the client is to become a member of the wireless network. The term association is used to describe that a wireless connection has been obtained.

Basic Service Set

introduces a central *access point* to improve performance

What is the problem with the BSS?

users can travel outside the radio range of a station's wireless link with one access point

Router

__________________ connects your devices to the modem (and each other).

A _______________ connects extra computers to the router

Switch

*Wireless LAN adapter provides:*

*Delivery of the data* *Authentication* *Privacy*

*Guidelines for wireless security:*

*Make sure the wireless security features are turned on.* *Use firewalls and intrusion detection* on your WLAN. Improve authentication of the WLAN by *incorporating 802.1x features*. *Consider using third-party end-to-end encryption software* to protect the data that might be intercepted by an unauthorized user. Whenever possible, *use encrypted services such as SSH and Secure FTP.*

RFID are classified based on how they power the *tag*:

*Passive* *Semi-active/Semi-passive* *Active*

Bluetooth (IEEE 802.15)

*Short-range* wireless communication technology developed to replaced the cables connecting electronic devices Operates in the 2.4 GHz range

IEEE 802.11a equipment is

*not* compatible with: 802.11b 802.11g 802.11n

Next, it enters the

*paging procedure* used to establish and synchronize a connection between two Bluetooth devices.

Since wireless LANs have a maximum distance the signal can be transmitted; What solution can help?

*place multiple wireless access points* within the facility It is important to verify that a *sufficient RF signal level* is available for the users in the WLAN

Backscatter

*reflection of the radio waves striking the RFID tag and reflecting back* to the transmitter source with its stored unique identification information

*Semi-active/Semi-passive*

*tags use a battery to power the electronics on the tag but use backscatter* to transmit info back to the reader

PC's come with a _________________________________

*wireless LAN adapter card* that connects the device to the wireless medium

*The other wireless technologies that you can read about*

-3G -4G -LTE *refer to the generation of network technology*

Tags typically carry no more than:

2KBytes of data just enough to store basic information about the item it is on.

Examples of other wireless technologies RFID:

Amusement parks Pet's microchip Passports Librairies Scanning Toll Roads

Infrastructure Mode:

Basic Service Set (BSS) Extended Service Set (ESS)

A router connects all your home's devices to each other through _________________________ then connects to the modem.

Ethernet cables or Wi-Fi

Routers come with built in

Ethernet ports

Disadvantages of wireless networks:

General *speed is slower than wired* *Limited range and connections* can be obstructed by physical structures *Less secure*

802.11ac

Wi-Fi 5 5G Wi-Fi 5GHz

WPA2 =

Wi-fi Protected Access II *Uses a stronger encryption method than WPA* *It is used on all certified Wi-Fi hardware since 2006* and is *based on the IEEE 802.11i* technology standard for data encryption.

802.11a

Wireless A Up to 54Mbps and 75 feet 5 GHz OFDM

Modem

connects you to the Internet

Network administrator

must assume that wireless data can be received by unintended user, and should *secure the wireless network.*

SSID (Service Set Identifier)

name of the wireless network; used to identify what wireless data traffic is allowed to connect to the network.

WEP encryption has ___________ known vulnerabilities that make it susceptible to ______________ techniques.

several; cracking

Extended Service Set (ESS)

use of multiple access points to extend the range of mobility of a wireless client in the LAN.

As part of the association process, a wireless network interface card (NIC) must have the same ________ as the access point or it will not be permitted to join.

SSID

Make sure the wireless security features are turned

"ON"

Transceiver

(transmit/receive) *interconnects data from the wireless LAN to the wired network*

What are the two basic wireless modes (topology) of the WLAN?

*Ad Hoc Mode* *Infrastructure Mode*

*Active*

*USES* a *battery* to power the tag and transmit a signal back to the reader*

*Piconet* is an ____________ network.

*ad-hoc*

Access Point ___________________

*add wireless connectivity* Connects to your router, usually over Ethernet, and communicate with your Ethernet-less devices over wireless frequencies.

Most of the standards are

*backward compatible*

WPA3 =

*details released in 2018*, full implementation; *NOT* expected *until 2019*

*Passive*

*has no battery* to power the circuit; it draw power from the reader, which sends out electromagnetic waves the tide a current in the tag's antenna

What is the Ad Hoc Mode composed of?

*individual devices communicating directly with each other* rather than through a centralized access point.

What are the difference between access point and router?

A *Router* is a device that sends packets to destinations (routes them). And an *Access point* is a device that allows wireless devices to connect to it by means of the antennas.

RFID uses the principle:

Backscatter

*WEP is the_____________ standard for securing wireless networks* by *encrypting/decrypting* wireless packets.

FIRST

Another name for Ad Hoc Mode is?

Independent Basic Service Set (IBSS) or Point-to-Point

Access point typically uses an

RJ-45 jack to connect to the wired network

Wireless 802.11 LANS: *Security*

Radio frequencies(RFs) used in wireless can pass through walls, ceilings, and floors

Why is network security important?

Unlike wired networks, wireless radio frequency(RF) signals literally traverse the open air. RF signals are completely exposed to anybody within range *If wireless access point is not properly secured, other people can gain access to it.* *A person who can connect to your wireless network may be able to do the following:* ○ *View files on your computer* or laptop and spread a virus ○ *Monitor websites that you visit*, copy login names and passwords, and read emails ○ *Slow down your computer* or laptop and the Internet connection speed ○ *Send spam and/or perform illegal activities* using your Internet connection

*WPA =*

Wi-Fi Protected Access; WPA numerous flaws in WEP showed an urgent for a replacement standard.

*WEP*

Wired Equivalent Privacy

802.11b

Wireless-B Up to 11 Mbps and 100-150 feet 2.4 GHz DSSS

802.11g

Wireless-G Up to 54Mbps and 150 feet 2.4 GHz DSSS/OFDM

802.11n

Wireless-N Wi-Fi4 Up to 54Mbps and 150 feet 2.4 GHz DSSS/OFDM

Site Survey key information:

[Indoor] *Electrical power* *Wired Network connection point(s)* *RF coverage - user mobility* *Bandwidth supported* *Identify any significant RF interference* [Outdoor] *Electrical power (base access point)* *Connection back to the home network* *Bandwidth supported* *RF coverage* *Identify any significant RF interference*

Standalone modems

__________________________ aren't able to send data to multiple devices simultaneously: *they usually only have one Ethernet port, and only produce one IP address*, which identifies your location to the internet

Internet Service Provider (ISP)

_______________________________ generally *provides modem for a small monthly fee.*

When complete,

a *connection (piconet)* has been established.

RFID tag *RF transponder*

a microchip and antenna

One solution to solve BSS problem is to?

add multiple access points to the network.

Bluetooth networks

also called *piconets* use a *master/slave* model to control data flow

RFID reader transmits

an encoded radio signal to interrogate the tag.

Wireless AP is a ____________ between the wireless devices and wired network - there's a wire connecting it to the network.

bridge

Single master device

connect up to *7* different slave devices. Any slave device in the piconet can only be connected to a single master.

WPA was the

interim standard released while an improved, long-term security standard was being worked on. *Still Vulnerable*

Site survey inside a building:

is performed to determine the best location(s) for placing the access point(s) for providing maximum RF coverage for the wireless clients.

*Association*

is used to describe that a wireless connection has been obtained.

If a bluetooth device is discovered,

it sends a reply back to the initiating device.

e.g 802.11a "a"

letter portion it signifies both the generation and the manipur sped you can hope to transmit or receive between the base station and other wireless devices.

RFID tag receives the

message and then responds with its identification and other information .

Cable, fiber optic, or telephone line comes through your neighborhood, to your house, and connect to your ____________.

modem

Access Point

pierce of hardware that allows a wireless device to connect to a wired network; also called *AP* *Wireless AP* *WAP*

*A reader*

sends out electromagnetic wave and has an antenna for receiving data

Wifi heat map

software can help identify max coverage and dead zones. A map of wireless signal coverage and strength .

If you run out of ports, a ______ can add more Ethernet ports to your network.

switch

Roaming

term used to describe a user's ability to maintain network connectivity as he *moves through* the workplace.

Radio Frequency Identification (RFID):

uses a radio waves to track and identify people, animal, objects, and shipments.

Bluetooth connection process when enabled:

uses an *inquiry procedure* to determine if any other Bluetooth devices are available; procedure also allows itself be discovered

Extended Service Set (ESS):

uses multiple access points to *extend* the range of mobility of a wireless client in the LAN.

Hand-off

when the user's computer *established an association with another* access point

IEEE 802.11 (Wi-Fi):

worlds most widely used wireless computer networking standards.

Backward compatible

you can replace a router at home right now with a newer router and existing wireless devices, such as your laptop, iPad, iPhone, and so on, no matter how old, will still connect to your network the way they have always worked.