Wireless Performance - more
Scenario 3 - 11b associated and simultaneously active
Once 11b clients connect to your AP, sooner or later they're going to start using it! Figure 11 shows one example of what you might expect.
Figure 11: Linksys WPC54G & NETGEAR MA401 Stations
The screen shot shows a test done with Linksys WPC54G and NETGEAR MA401 clients. The Linksys draft-11g card starts first, and is joined by the NETGEAR 802.11b card at the 20-second mark. Both cards run until the Linksys card completes its programmed number of transfers and stops, letting the NETGEAR card finish by itself.
• Two separate Ethernet client machines were used to avoid overloading any single CPU,
• All clients were on the LAN side of the router, so the routing portion of the product is not involved in the test.
The plots clearly show that the Linksys draft-11g client's throughput really takes it on the chin, dropping well below the NETGEAR 11b client's. The effect, however, is once again client dependent, as shown in Figure 12.
Figure 12: Two pair test - NETGEAR WAB501
This second screen shot shows the same test, but this time with the second card being a NETGEAR WAB501 Dual-Band client forced to 802.11b mode. This test shows behavior more like what you should expect in all cases, once Linksys gets its firmware released that has draft 6.1 improvements, which mandate that 11g clients get more air time than 11b clients in mixed WLANs.
802.11g Wireless Performance Test Results
- WEP encryption: DISABLED
- Tx Rate: Automatic
- Power Save: disabled
- Test Partner: Linksys WPC54G Wireless-G Notebook Adapter
1.01.4 Jan 27 2003
Wireless client driver:
Wireless client f/w:
|Test Description||Signal Quality (%)||Transfer Rate (Mbps)||Response Time (msec)||UDP stream|
|Throughput (kbps)||Lost data (%)|
|Client to AP - Condition 1||0||21.2
|Client to AP - Condition 2||0||20.5||1 (avg)
|Client to AP - Condition 3||0||11.6||60 (avg)
|Client to AP - Condition 4||0||4.8||8 (avg)
See details of how we test
Although the WRT54G is street priced about the same as its WAP54G access point sibling, the choice may not be as easy as it seems. Even though the router can always be used as an access point, it does not include the wireless bridging capabilities found in the WAP54G. If you need both routing and bridging in a draft-11g router, you should look at Buffalo Tech's WBRG54, which throws in wireless repeating, too.
Like all draft-802.11g products, the WRT54G is a work in progress on its wireless side, and will remain so until the 802.11g spec is released this coming June. On the positive side is that Linksys appears to be leading the pack in wireless throughput with a top speed of about 21Mbps. Linksys' weakness however, is its handling of mixed WLANs which in some cases can slow draft-11g clients to a crawl.
NOTE: A quick look at the latest 1.06 firmware for the WAP54G, which is supposed to incorporate draft-11g version 6.1 mechanisms, showed me that Linksys still has work to do to handle mixed WLANs smoothly. The new code made the WAP54G behave similar to, but not better than the WRT54G with its 1.01.4 firmware.
In addition to these wireless issues, the routing side also needs work to bring it up to par with the rest of its Linksys siblings because of the newer Broadcom-based routing platform. These "to-do's" don't seem to be holding the WRT54G back though, at least according to Linksys, which expects to ship more than 500,000 Wireless-G products by the end of this month (March 2003).
Call me conservative, but I still think there's an advantage in holding off for another month or so. Not only will you get to skip one or two firmware update cycles, but you'll also get more products to choose from, including the tri-mode dual-band (a/b/g) products that have been announced by NETGEAR and should start appearing in on-line stores shortly. Although these products will start out at a price premium to single band b/g products, once the enterprise folks start buying tri-mode dual-band clients, their volume could drive tri-mode prices down to where they're the logical choice.