802.11g NeedToKnow - Part 2

5. Draft-11g - WEP effects

Unfortunately, for Intersil at least, this isn't the only bad throughput news. My testing also showed an approximately 10% WEP-enabled throughput hit, which is shown in Figure 5.

Figure 5: Intersil - with and without 128bit WEP enabled
(click on the image for a full-sized view)

These results caused me to go back and rerun the same test on the Linksys pair, with the results shown in Figure 6.

Figure 6: Broadcom - with and without 128bit WEP enabled
(click on the image for a full-sized view)

Although there's a slight difference of about 1%, I'd say the difference is well within the uncertainty of the measurement and therefore not significant.

The result of all this is that with 128bit WEP enabled, Broadcom's average throughput advantage over Intersil - with 11g stations only and no 11b clients in range - increases to about 35%. When I asked Intersil whether they would be able to make the WEP-enabled throughput hit go away, I was assured that the slowdown was due to early firmware, and would be "ironed out" in a future release.

But before you start taking Intersil-based draft-11g products off your shopping list, you'd better take a look at what happens when 802.11b stations are added to the picture.