PACE-IT: Wireless LAN Infrastructure (part 2)

Wireless LAN infrastructure II.

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Instructor, PACE-IT Program – Edmonds Community College

Areas of expertise Industry Certifications

PC Hardware

Network Administration

IT Project Management

Network Design

User Training

IT Troubleshooting

Qualifications Summary

Education

M.B.A., IT Management, Western Governor’s University

B.S., IT Security, Western Governor’s University

Entrepreneur, executive leader, and proven manger with 10+ years of experience turning complex issues into efficient and effective solutions.

Strengths include developing and mentoring diverse workforces, improving processes, analyzing business needs and creating the solutions required— with a focus on technology.

Brian K. Ferrill, M.B.A.

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Wireless LAN infrastructure II.PACE-IT.

– Basic WLAN topologies.

– WLAN concepts and terms.

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Basic WLAN topologies.Wireless LAN infrastructure II.

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– Ad hoc topology.» A very basic wireless local area network (WLAN)

that does not require the use of a wireless access point (WAP)—also known as an access point (AP).

» Devices negotiate the wireless connection between themselves (e.g., laptops connect wirelessly without the use of a WAP).

– Infrastructure topology.» A more common type of WLAN that uses a WAP or

WAPs to create a connection point for wireless devices.

• Most often connects a WLAN to a more traditional wired network, but it is not absolutely required.

– Mesh topology.» A type of infrastructure topology that employs the

use of multiple APs to create a larger seamless network coverage area.

• Commonly deployed with wireless controllers and WAPs.

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Something to remember is that the higher the wireless device density, the more WAPs that will be required to handle the load.

Like any other network device, APs only have a certain amount of capacity. As the workload increases, the amount of throughput will decrease as each device contends for access to the WAP.

Adding more WAPs and/or adding more WAPs and a wireless controller can greatly ease the load and increase the efficiency of the network.


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WLAN concepts and terms.Wireless LAN infrastructure II.

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IBSS.

Independent basic service set.

An IBSS is created when an ad hoc network topology is created. The devices use the IBSS in order to control the communication that occurs between connected devices.

BSS.

Basic service set.

When a single WAP is in infrastructure mode, it will create a BSS. This means that it can control the flow of communication between every device that connects to the SSIDs under its control.

ESS.

Extended service set.

An ESS is created when two or more APs share a common SSID and have overlapping coverage. Through the ESS, the WAPs will negotiate how to hand off a wireless device between them as it roams the network.

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The service set identifier (SSID) plays a key role in the WLAN environment.

All active WAPs will use a beacon transmission to advertise the networks that they belong to. What they advertise is their SSIDs—their network names. Those beacons are how devices know which networks they can connect to.

Even when the AP is set to hide the beacon, the broadcasts are still occurring. Although hiding the SSID broadcast may make it more difficult to join a wireless network, it is not a true security measure.


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– 802.11a-ht and 802.11g-ht.» Both terms relate to the 802.11n standard.

• Denote the type of connection—high throughput, and the radio frequency—either 2.4 GHz or 5GHz of the connection.

– Goodput.» The actual amount of application data passed through

a connection with the overhead removed, measured in bytes per second.

» It is different than throughput.• Throughput measures the total amount of data

capable of being passed through a connection.

– Signal strength.» A measure of the strength of the RF signal from an AP,

which can help to determine coverage area.• As a general rule, the closer a device is to the WAP,

the stronger the signal received.» The strength of a signal can be affected by WAP or

antenna placement, type of antenna, and interference sources, etc.

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A wireless site survey with heat mapping tools can help in the set up of a WLAN or it can help to pinpoint problem areas.

Heat mapping software builds a visual map by measuring received signal strength indicator (RSSI) and signal to noise ratio (SNR), which can be directly correlated to data throughput.

Using these tools allows the administrator to find gaps in coverage as well as areas where the coverage extends beyond the desired boundaries.


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What was covered.Wireless LAN infrastructure II.

In an ad hoc network, wireless devices connect without an AP, using an IBSS. In an infrastructure network, one or more WAPs control access to the network through a BSS. A mesh network is a type of infrastructure wireless network that uses multiple APs to seamlessly provide network coverage over a larger area through the use of an ESS. As device density increases, more WAPs can be added to distribute the load.

Topic

Basic WLAN topologies.

Summary

WAPs send out a beacon that contains the SSID (the network name). Hiding the SSID doesn’t stop the beacon from being broadcast and is not an effective security measure. Goodput is a measure, in bytes per second, of actual application data that can be transmitted. The closer to the AP that a wireless device gets, the stronger the signal. Site surveys and heat maps can be used to set up efficient wireless networks and to pinpoint problem areas.

WLAN concepts and terms.

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THANK YOU!

This workforce solution was 100 percent funded by a $3 million grant awarded by the U.S. Department of Labor's Employment and Training Administration. The solution was created by the grantee and does not necessarily reflect the official position of the U.S. Department of Labor. The Department of Labor makes no guarantees, warranties, or assurances of any kind, express or implied, with respect to such information, including any information on linked sites and including, but not limited to, accuracy of the information or its completeness, timeliness, usefulness, adequacy, continued availability or ownership. Funded by the Department of Labor, Employment and Training Administration, Grant #TC-23745-12-60-A-53.

PACE-IT is an equal opportunity employer/program and auxiliary aids and services are available upon request to individuals with disabilities. For those that are hearing impaired, a video phone is available at the Services for Students with Disabilities (SSD) office in Mountlake Terrace Hall 159. Check www.edcc.edu/ssd for office hours. Call 425.354.3113 on a video phone for more information about the PACE-IT program. For any additional special accommodations needed, call the SSD office at 425.640.1814. Edmonds Community College does not discriminate on the basis of race; color; religion; national origin; sex; disability; sexual orientation; age; citizenship, marital, or veteran status; or genetic information in its programs and activities.