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| What Is a Wireless LAN? |
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A wireless LAN (WLAN) is a local area network (LAN) that uses high-frequency radio (usually 2.4 or 5.8Ghz) waves rather than wires to communicate between nodes. It allows mobile users to connect to a LAN through a wireless (radio) connection. FSU views this network as a data communication system that can extend, enhance, or replace (in some instances) a wired LAN. It provides connectivity where wiring is unavailable or cost prohibitive. It is a flexible, cost effective alternative to providing additional functionality to our existing LAN. |
| Why Wireless LAN? |
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Imagine you are a shipping company. Wouldn’t you like to have the ability to scan in bar codes on boxes that explain shipping arrivals and departure times? Ultimately, you could reprint labels for rerouting a package in mid-transit.
How about a big auto parts warehouse, or a grocery warehouse? Inventory will be directly input into a database that generates orders directly to your vendors.
For a medical staff, records could be available immediately, rather than waiting for someone to deliver them. You could write follow-up visits, print notes, and transcribe your own treatment plans in real-time. All of this information could be printed and waiting at the front desk for checkout.
You can take your laptop on the road and experience high-speed wireless Internet access in hotels, airports, conference centers, and other areas while you travel.
In the past, as a "technician," you would have to visit a customer, gather information, and then go back to the office and try to remember what you needed for each transaction. With a wireless network, you could go visit the customer and generate the order from their location, explain any additions, have the information automatically generated in your database, and begin the next step of the process while onsite. This provides a more accurate and timely management of information. |
| How They Work! |
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Wireless LANs use electromagnetic airwaves (radio and infrared) to communicate information from one point to another. The data being transmitted is carried on radio waves and is extracted at the receiving end.
In a typical WLAN configuration, a transmitter/receiver (transceiver) device, called an Access Point (AP), connects to the wired network from a fixed location using standard Ethernet cable. At a minimum, the AP receives, buffers, and transmits data between the WLAN and the wired network infrastructure.
End users access the WLAN through wireless LAN adapters, which are implemented as PCMCIA cards in notebook computers, as ISA or PCI adapters in desktop computers, or as fully integrated devices within hand-held computers. WLAN adapters provide an interface between the client network operating system (NOS) and the airwaves (via an antenna). The nature of the wireless connection is transparent. |
| RANGE |
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The distance over which RF waves can communicate is a function of product design (including transmitted power and receiver design) and the propagation path, especially in indoor environments. Interactions with typical building objects, including walls, metal, and even people, can affect how energy propagates, and thus what range and coverage a particular system achieves. Most WLAN systems use RF because radio waves can penetrate many indoor walls and surfaces. The range (or radius of coverage) for typical WLAN systems varies from under 100 feet to more than 300 feet. Coverage can be extended.
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Figure 1: Implementation at 30mw output (2.4Ghz).
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Figure 2: Implementation at 100mw output.
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| Throughput |
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As with wired LAN systems, actual throughput in wireless LANs is dependent upon the product and how it is configured. Factors that affect throughput include RF channel congestion (number of users), propagation factors such as range and multipath, and the type of WLAN system used, as well as the latency and bottlenecks on the wired portions of the WLAN. Typical data rates range from 1 to 11 Mbps (see Figure 3). |
| How WLAN's Assist FSU |
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FSU is implementing an infrastructure that will compliment our wired network. The goal is to use wired computing labs for more intensive computing applications and provide students and faculty with flexible solutions that would enable mobile connectivity on campus and mobile computing from remote locations.
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Before we get too far ahead, let’s look at how FSU started its implementation of WLANs. |
| FSUWIN - What Are We Doing? |
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FSUWIN is the Wireless Integrated Network solution at Florida State University. Our purpose is to use the WLAN as a flexible, cost-effective alternative to providing additional functionality to our existing wired LANs. Our implementation started as a means to upgrade the existing 1-2MB Wave LAN technology we had on campus. We look at it as a two-part construction and installation process. Part I was Building-to-Building Connectivity (Bridges), and Part II was Intra-Building Connectivity (AP). |
| Part I, Phase I – |
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FSU has established temporary LANs for a few buildings that were slated for renovations and/or destruction. With the wireless network, we could quickly install a small network, wirelessly associate it to our existing network, remove it, and place the equipment into a new building that would need connectivity. As mentioned, this involved removal of 1-2 MB WaveLAN connected buildings and upgrading them to the 11MB Wireless product. This included 6 buildings and approximately 89 users. We took 4 buildings and made two domains in two points of connectivity to the FSU network. Since then we have added an additional building to each domain. By upgrading, we increased bandwidth, fixed connectivity issues, and hid antennas. The costs for these connections were between $3,000 and $6,000, whereas a single fiber connection would have incurred a minimum of $10,000. |
| Part I, Phase II – |
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Part of our installation structure was to install small groups or departments first. We looked at places/departments just outside the FSU campus footprint and found staff members who were using our dial-up connections. This process was used to review all of Florida State’s extended campus. We located buildings that were not permanently connected to the network and those that had the most individuals using modems to connect to the network. We determined that we could wirelessly connect these buildings and return 25 modem lines to our wired network pool. Using a wireless solution, FSU was able to eliminate 37 dial-up connections in 5 buildings, thus freeing dial-up resources for more individual users to connect during any given period. |
| Part I, Phase III – |
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This phase involved adding 8 additional building with approximately 81 users. These buildings were either "off-campus" locations or too expensive for the number of users required to justify the cost of fiber connections. One location is approximately 1.5 miles away, another is already close to an existing Wireless connection, and another spanned "city" streets, which would mean recurring costs. We spent approximately $15,000 without recurring costs or permits. |
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Our building-to-building connections now cover 19 buildings with 207 users and 22 bridges. We even connected another building for a short time as temporary staffing. |
| Part II, Phase I – |
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This phase determined areas of campus where WLANs would benefit the campus as a whole. We have three libraries and part of our Student Union connected. Our Student Union is a gathering place for students, employees, and vendors. We were asked for network connections that could not be provided otherwise.
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| Part II, Phase II – |
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This involves assisting departments with the connection of WLANs for their personal use. |
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Our intra-building connections consist of 58 AP’s and are slated for support of approximately 1160 users. |
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FSUWIN is more than just installing and configuring WLAN’s. For those departments interested, we assist with the implementation, integration, optimization, and installation processes required for a successful wireless operation. FSUWIN knows that the wireless networks have occasional limitations, and we make sure departments do not encounter various situations that can be resolved with wireless propagation studies. When setting up a WLAN, factors such as frequencies and range need to be taken into consideration, along with other wireless devices that may be co-located near the area. In order to ensure maximum efficiency of wireless devices, FSUWIN offers: |
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- Liaison for ordering and installation of equipment
- Performance of site surveys
- Determination of the number of APs for immediate and future growth/improvements
- Full documentation of installation, including frequencies used, locations, setup information, information on growth, and monitoring of devices
- Maintenance and troubleshooting of devices
- Documentation for ourselves in terms of location and channel assignment, number of devices (co-location), and knowledge of future installations
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Individual departments that have used our services (as Part II, Phase II) are College of Law, Registrar’s Office, College of Business, School of Social-Work, and Mathematics. |
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