4. Draft-11g Vendor Interoperability

This category includes interoperability issues that come from mixing products from different networking product vendors, with the primary effect being throughput variation. In Part 1 of this NTK, I had only products based on Broadcom's draft-11g chipset to play with, and was still able to show a significant difference in performance between the Buffalo Technology and Linksys products tested. This time, I was able to add Intersil-based products to the mix, and found yet another variation in throughput behavior.

NOTE: Since I was unable to obtain review product from D-Link after repeated attempts, I worked directly with Intersil - the maker of the wireless chipset that D-Link uses in their "Xtreme G" draft-11g products. Although I can't say which specific products I used for my testing, let's just say that the results should be representative of Intersil-based products that you can buy today.

Figure 2: Intersil, first version

(click on the image for a full-sized view)

Figure 2 shows the performance with the first available firmware for the Intersil devices. As with my other tests, I used both a client and AP based on the same (in this case Intersil) chipset, and had no 802.11b clients active for this test. You can see a relatively steady throughput characteristic, but slower than the throughput obtained with Broadcom-based products.

After reporting my results to Intersil, they sent new client and AP firmware (which has since become publicly available), which I installed and used to generate the results shown in Figure 3.

Figure 3: Intersil, first vs. new versions
(click on the image for a full-sized view)

The resulting 35% throughput improvement was not bad, but as Figure 4 shows, still not equal to the latest available Broadcom-based products.

Figure 4: Intersil new vs. Broadcom new
(click on the image for a full-sized view)

Figure 4, which compares Intersil based product with the Linksys WRT54G router and WPC54G CardBus card, shows an approximately 18% throughput advantage for the Broadcom-based Linksys pair.