Wireless LAN Evaluation Guide
Contents ii Introduction ________________________________________________________________________ 1 Technology overview _______________________________________________________________ 1 DSSS ___________________________________________________________________________ 1 FHSS ___________________________________________________________________________ 1 Preparing the test ____________________________________________________________________ 2 Recommended test equipment and setup _____________________________
Introduction 1 Introduction Because wireless LAN technology is still new and dynamic, Proxim has created this guide to outline considerations for both the writer to address in wireless review "write-ups" and the reviewer or IT manager to address in wireless comparison testing. To an end user, well designed wireless LANs provide equivalent functionality to wired networks and seamless access to network resources without the need to be physically tethered.
Preparing the test 2 narrowband interferer. If interference occurs on one frequency, then the data is simply retransmitted on a subsequent hop. Noise on any given frequency will typically be absent after hopping to another frequency. All FHSS products on the market allow users to deploy more than one channel in the same area. They accomplish this by implementing separate channels on different, orthogonal, hopping sequences. Because there are a large number of possible sequences in the 2.
Preparing the test Required equipment 1 Access Point 1 Client (laptop with wireless PC Card) 1 Server (desktop PC with Ethernet adapter) 10Base-T Ethernet Hub 3 Recommended software tools § Integrated web based management tool § Windows 95 or other peer-to-peer NOS § TCP/IP protocol stack with support for § § § § ping , telnet and FTP Site survey tool Windows 95 or Windows NT NOS TCP/IP protocol stack with support for ping , telnet and FTP None Comment Simplifies advanced configuration Site survey tool
Preparing the test § 4 Make throughput measurements in the exact same location each time. This includes the relative height of the laptop. Antenna position and height can have a significant impact on results. A suggestion to ensure consistency is to set the laptop down in a specific spot on a table for each throughput measurement. Before you get started The range (and throughput) of any wireless LAN solution is affected by the composition of material in the floors, walls and ceilings of any building.
Preparing the test 5 The link quality is a measurement from 0-5 recording roughly how many packets sent out by the site survey tool are being received by the adapters within range. A reading of 5 means that most of the packets are being received while a reading of 0 means that only a few packets are received (or that the remote node is in Doze mode.) The received signal strength parameter measures the radio signal strength between the various LAN adapters and the site survey machine.
Recommended test program 6 different places or try different antenna placement options to see if it affects your measurements. Place the Access Point in the best location that produces the highest overall numbers for the area you want to cover. Note: To get a stable read of the throughput for a specific position, load the directed link site survey tool and let the wireless client sit for a period of time that you specify. Then take a note of the average packets/sec and bytes/sec results.
Recommended test program 7 Evaluating mobility parameters Wireless LANs are targeted towards mobile computing platforms such as laptops, Windows CE handheld PCs, barcode scanners, pen tablets and more. Since these devices are battery powered, a wireless LAN adapter that uses as little power as possible is critical to maximize operating time without battery change or recharge.
Recommended test program 8 In addition to the Suspend & Resume mode, Proxim’s RangeLAN802 PC Cards and design-in modules support the Hibernate state per the 802.11 specification. In this mode, the client minimizes power usage while remaining synchronized to the master.
Recommended test program 9 There are a number of ways to benchmark performance of a wireless LAN. Here are a few that are commonly used for product reviews and comparisons. Proxim does not recommend one method or the other except for the fact that the same test should be used in each configuration for comparison. 1. File transfer 2. Printing 3. Loading applications over the network 4.
Recommended test program 10 Continue to measure the throughput moving the client to various points within the network using the locations on your building map. Measure the throughput at locations near the fringe of range. As the client moves farther and farther from the Access Point, the throughput will begin to degrade. Robust implementations allow communication to slowly drop off as the client reaches the fringe of coverage.
Recommended test program 11 Factors promoting ease of installation and management (continued) Factor Value Easy firmware downloads from any AP across the network to all other APs The network manager needs to physically upgrade only one device and thus saves time Product operates equally on all hardware platforms Software tools support all major operating systems; user does not have to purchase additional hardware Already tested on hundreds of Product will work regardless of hardware platforms the har
Recommended test program 12 same time, there is a chance that unit B will never communicate with the Access Point. Robust radio protocols ensure that all units can communicate regardless of the distance from the Access Point. In this example, both unit A and unit B should be able to communicate at all times with the Access Point. Hidden terminal Another scenario you might encounter and should evaluate is the "hidden terminal" phenomenon.
Recommended test program Nov 98 13
Reviewer checklist 14 Proxim RangeLAN2 Proxim RangeLAN802 Yes - #7510/752x Yes - #753x Yes - #852x Not yet Yes - #7100/740x Yes - #791x Yes - #792x Yes - #840x Not yet Not yet Yes Yes Yes Yes Yes Yes Yes Yes Yes Not yet Network, platform and O/S support LAN connectivity Ethernet Token Ring Platform support Intel-based platforms Devices with Ethernet interface Devices with serial interface Driver support ODI NDIS Windows 95 Windows NT Windows CE Performance test results Range Indoor Outdoor Throug
