Test Drive: D-Link DWL-900AP+ AirPlus 2.4GHz Wireless Access Point

By SmallBusinessComputing Staff | Posted November 04, 2002
By Ronald Pacchiano

If I was in the market for a new wireless access point the first thing I would do is start looking for products based on the IEEE 802.11a standard. Compared with the older 11Mbps 802.11b products, 802.11a hardware can support data transfer rates approaching 54Mbps. That speed however, comes at a price - 802.11a products are usually quite a bit more expensive, are not backwards compatible with 802.11b components and typical suffer from shorter range. In spite of this, the promise of speed can be very seductive and difficult to ignore. So perhaps a compromise is in order?

The new DWL-900AP+ AirPlus access point from D-Link Systems is based on the latest so-called 802.11b+ technology. This means that it is not only cheaper then 802.11a products, but also maintains compatibility with other 802.11b hardware. The "Plus" means it is capable of achieving speeds approaching 22Mbps. Not bad huh? Speed however, isn't the only selling point of the AirPlus. With a street price of around $100, D-Link has equipped the AirPlus with impressive features not easily matched by other products.

Basic Features
The key to the AirPlus's speed is the Texas Instruments (TI) ACX100. This chipset operates in the 2.4GHz radio spectrum and employs the modulation technology called Packet Binary Convolutional Coding (PBCC) which allows users to take advantage of higher wireless speeds while still maintaining compatibility with existing 802.11b networks. Of course, in order to take full advantage of these higher performance levels you need to be using a wireless NIC that makes use of this same chipset. D-Link's own AirPlus DWL-650+ wireless Cardbus adapter or AirPlus DWL-520+ Wireless PCI adapter both fit the bill. If you use a network adapter with the ACX100 chip, the best you can hope for will be the standard 11Mbps.

Versatility is another nice feature of the AirPlus. It can be operated in one of five different service modes. The first is access point; which operates as a communication point for wireless computers bridging them to an Ethernet LAN. This is the mode which will be used by the majority people.

The next two modes are a Wireless Bridge and a Wireless Multi-point Bridge. In the wireless bridge mode you use two of these units to create a dedicated bridge between two wired networks. Just connect one access point to each LAN and they will appear to be a single LAN. The Wireless Multi-point Bridge works the same way, but allows you to join multiple LANs together.

During the course of this review D-Link released a new firmware version (v2.2) which added an additional operating mode to the AirPlus's already impressive arsenal. This new mode allows the AirPlus to act as a Wireless Repeater for D-Link AirPlus and AirPro products, extending the range of these products by up to 50%.

The last service mode is called Wireless Client. It works in the same way as an Ethernet to wireless bridge. Just configure the AP and then connect it to any device with an Ethernet port. A good use of this feature could be with a game console with Ethernet, such as the Sony PlayStation 2 or Microsoft Xbox. This would give the units broadband Internet access without the need for additional cables spread out in the middle of your living room.

While most SOHO users won't take advantage of most of these features, it's nice to know you have them if the need should arise.

Setup/installation
It continues to amaze me how easy it has become to add a wireless access point to a network, even for users with little or no network experience. The DWL-900AP+ comes preconfigured with a default IP Address of 192.168.0.50. So as long as you have a system that resides on that same subnet you'll have no problems. If not, you'll need to temporarily reconfigure one of your workstations to get in and change the access point's settings.

Change a workstation's IP address to 192.168.0.1. The first three octets should match. Use your Web browser to surf to 192.168.0.50 to bring up the access point configuration tool.

At that point it will prompt you for your username and password. When you login, a configuration wizard will guide you through the setup; walking you through such tasks as changing passwords, establishing a network ID, and initiating encryption. The wizards work well and will be enough for the majority of users. For those who want to handle the configuration chores on their own you'll find the Web-based menu system very straightforward and simple to navigate.

Other features within the menu system include the ability to review access logs, search for updated firmware and even backup and store the unit's configuration files. These configurations can also be used to configure additional access points for multi-bridge deployments. For the more technically minded, the 900AP+ provides users with a complete readout of network traffic statistics. Built-in DHCP services can be enabled on the access point itself to make managing your wireless workstations easier. One of the most interesting features of the 900AP+ is its new repeater functionality. This is the first wireless repeaters available, particularly at this price point. In order to test this feature, D-Link also sent us an AirPlus DI-614+ wireless router.

The first step in testing the repeater function was to measure how far away we were able to get from the 614+ router before losing the signal. I connected the 614+ to my cable connection (located in the basement), then moved up to the first floor and proceeded out the front door. When I lost the signal, I was approximately 55ft away from the router. Now that I had my target distance, I proceeded to configure the repeater. In order to repeat the signal the 900AP+ needs to know the MAC address of the router. The 614+ however has three MAC address; One for the LAN, one for the WAN and one for the wireless adapter; so we weren't exactly sure which one we were suppose to use. After a bit of trial and error, we discovered that the LAN address was the one we needed. Once I entered the required information I moved the 900AP+ upstairs next to my front door.

I brought my notebook back to the place I had originally lost the signal and discovered that I still had no signal with the repeater in place. Hmmm.

The 650+ PC Card NIC that I was using has a site survey utility which scans for wireless networks. I initiated a scan, rediscovered my network and connected to it. Upon reconnection by signal strength shoot back up to 100%. It appeared to be working. So I started walking away from the unit. I kept walking and walking until I was finally about 140ft from the router. My signal strength hovered somewhere in the 72% range and the link quality indicator was in a constant state of flux, but I never lost the ability to browse. Impressive to say the least.

In the end the test system worked very well, but if you happen to run into difficulties with your installation, D-Link's free technical support is available 24 hours a day, 7 days a week. The DWL-900AP+ also comes with a generous 3 year warranty.

Performance
The press materials for the DWL-900AP+ boldly state that it delivers up to twice the performance of standard 802.11b products. During testing with the QCheck network testing utility I didn't notice any significant changes in throughput levels while working with standard 802.11b adapters. I then installed an AirPlus DWL-650+ PC Card in the test system and reran my performance test. With the DWL-650+ configured for 11Mbps we saw a relatively modest increase in throughput levels of about 10%. Enabling the AirPlus 22Mbps PBCC mode and transmission levels increased throughput tremendously - almost 48% over that of our standard 802.11b PC Card. In addition to the impressive performance enhancements, the range and reliability of our test unit was very good and we never experienced a dropped connection.

Usually when I enable encryption on a product the data transfer rates drop significantly due to the encryptions extra overhead. During my testing of the DWL-900AP+, regardless of whether I used 64, 128 or 256-bit encryption, the data throughput levels remained relatively consistent.

One of the most difficult things I run into during wireless product reviews is working with encryption. For some reason it is always a chore to get it working properly; sometimes on the client side, sometimes on the access point or router side. D-Link's encryption implementation worked flawlessly and was configured in a matter of minutes.

Security
Data security continues to be a hot topic and the DWL-900AP+ adds a number of security features to its arsenal. In addition to the standard 64 and 128-bit encryption found in most products, the AirPlus makes use of a class leading 256-bit WEP encryption. Obviously this encryption level can only be used with other D-Link products. The AirPlus also takes advantage of MAC address authentication. This technique allows you to control which systems can gain access to the wireless LAN by specifying their MAC address in the access point itself. This is especially useful in densely populated areas like dorms or apartments where someone is more likely to stumble upon your access point.

Summary
With so many good products on the market it is often difficult to decide which to purchase. Every once in awhile though a product comes along that seems to make that decision just a bit simpler. Today that product is the D-Link AirPlus DWL-900AP+. Its improved speed, 256-bit WEP encryption, easy to use navigation and setup wizards, 24 hour technical assistance, backwards compatibility and a really low price, all contribute to make the D-Link AirPlus DWL-900AP+ one of the best values on the market today.

Model Number: DWL-900AP+ ($129.99)

Pros: 256-bit WEP encryption; 5 service modes; easy set up and 24 hour support; high data transfer rates; backward compatibility; excellent range with repeater.

Cons: Repeater configuration difficult.

Reprinted from 80211-planet.com.

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