LANs /

Let's talk about NICs

By Mike Avery
Network World, 02/05/01

Looking at wireless network interface cards (NIC) from nine vendors was an eye opener. There are five basic take-home messages:

None of them are awful, but they all could be better.
If you have a desktop machine, you need an external antenna.
Processing power in the PC counts for a lot.
If you are still running Windows 95 that isn't OS Release 2 or later, it's time to upgrade.
There are only three companies that actually make these cards - everyone else is just putting their name on someone else's card.

The basic fact in wireless networking is that people usually don't want external antennas. A quarter-wave antenna for a 2.4-GHz card is about 1.25 inches long and a full-wave antenna is about 5 inches long, so it's not a matter of size, just preference. In using laptops with NICs with internal antennas, we found that small movements of the laptop caused large differences in signal strength. With desktops, we often found the path from the antenna to the access point led through the desktop machine, and performance was greatly impaired as a result. The vendors tell you that an external antenna will typically give about 15% more signal strength. Of greater importance is the ability to place the antenna to avoid obstacles.

In our first test of the Proxim NIC, we used a rather long in the tooth Compaq LTE laptop with a Pentium 166-MHz processor. The performance was so embarrassing we called the vendor to see if we'd done something wrong. Because we had been able to saturate a 10M bit/sec Ethernet with a single 100-MHz 486 processor, the processor shouldn't be an issue. We reran the NIC tests with a Toshiba Satellite with a 600-MHz Pentium III, and the results were much better. In looking at the Microsoft System Monitor, we found that any time we accessed the network - using any vendor's NIC - the processor utilization became quite high.

Putting your wireless house in order
Interactive Buyer's Guide database
Go ahead, cut the wires
How we did it
Interactive Scorecard and NetResults

Buffalo, Enterasys, Intermec and Lucent use the same 802.11 cards. They come from the same factory and have the same Federal Communications Commission ID. However, neither the prices nor the performance of these products are the same. In some cases, the products are packaged differently and have different firmware, so the lineage of the card is not as obvious. In others the vendor straightforwardly tells you that they will sell in an OEM capacity the cards from Lucent.

The difference in performance among these cards is in the drivers and their setups. The cards offer the usual internal antenna with antenna diversity selection. The cards also have a plug that can be removed to plug in an external antenna to improve range. These vendors offer PCI and ISA to PC Card adapters to let you use their NICs in desktop machines.

Buffalo uses a Ricoh-based card and warns in its manual that the ad-apter card can only be used with their PC Card NIC. We found that to be true - it wouldn't even recognize its stablemates. The Lucent PCI adapter will only work in an all-PCI system, so if your system has ISA and PCI slots, you can't use their PCI adapter, but must purchase the ISA card. Lucent says this will be fixed in a future revision of its PCI card. Intermec resells the Lucent adapter cards and has all the same problems that Lucent has. Enterasys uses a different vendor for its PCI to PC Card adapter, and their card worked very well. We don't think there is a real performance difference between the ISA and PCI cards when the bottleneck is the 11M bit/sec 802.11 topology, but we would rather not spend more money on ISA devices.

Cisco entered the wireless market through its recent purchase of Aironet. The 340 series PC Card installed easily, delivered good performance with every access point we used and offered very good diagnostic software. The 340 series PCI card features a permanently mounted 340 PC card and an external antenna. While the single external antenna causes the 340 to not be able to use antenna diversity, the results were excellent. Users willing to spend a few minutes with the card can add a second antenna - the connections are open, and the cabling is simple. In the end, we liked the diagnostic software so well we settled on the Cisco card to perform signal strength tests that we didn't wind up using in this review.

D-Link is the new kid on the block and it's targeting the small office/home office markets. The D-Link products have a PC card called the DWL-650. It's an attractive card that worked with all the systems we tried it on. It offered slightly better than average performance and was reasonably priced. However, it does not support an external antenna, which is a potential performance issue for desktop use. Unlike the Buffalo PCI ad-apter, the D-Link DWL-500 PCI card is a general adapter that should work with most PC cards. However, the installation is made somewhat awkward by poor layout - the card ejector button on the adapter makes it hard to put the card into a PC.

Intel and Symbol are in a marketing agreement for their 802.11b products (both NICs and access points), so the only differences between the products would seem to be in the name on the box and splash screens. Despite this, there are some performance differences between the cards in our testing.

Still, both performed well, and both installed easily in our systems. While the cards didn't excite us, they offer good performance for the money and were very easy to use in every system we put them in.

A final caveat is if you aren't using a Windows operating system, you need to pay special attention to the drivers that are available for the NICs. Few support FreeBSD, Linux or Macintosh. Windows CE support is still not quite here yet. If you don't check into drivers first, you could wind up with rather expensive paperweights.