Problemet med de "draft 802.11n"-produkter som finns är att de är mer eller mindre usla om man får tro de som testat dom.
Tom's Networking:
I have to join the chorus and advise against buying draft 11n products at this time. With high prices, immature drivers and firmware, no guarantee of upgrade to standard 11n when it's released and now - shown for the first time - evidence that some current products doesn't even perform better than 802.11g at lower signal levels, I can't think of an upside that justifies the expense and hassle.
In spite of vendor claims to the contrary, draft 11n has a long way to go until it gets to a maturity similar to what 802.11g had when draft 11g products started to ship. The industry and consumers would be better served if the manufacturers went back to their labs and standards meetings, hammered out the details and bugs and re-launched these products in dual-band form when they were really ready to ship.
AnandTech har också tittat närmare på de draft 11n-produkter som finns ute nu:
After reviewing the performance results we are generally disappointed in the current Draft N technology as it does not exceed the previous generation Pre-N MIMO products powered by the third generation Airgo chipset. While the Airgo based products contain proprietary technology and will never be upgradeable to 802.11n, they perform just as well or better than the current Draft N products whose manufacturers cannot guarantee full compatibility with the eventual 802.11n standard.
AnandTech berättar också att just Broadcom-chippet, som det påstås att Apple stoppat i iMacarna, är väldigt ovändligt mot grannät:
In our preliminary mixed mode testing we experienced the "bad neighbor" effect several times. Not only with our own internal 802.11g network but also visits from actual neighbors who were upset with having to constantly reboot their systems during our testing phase. As we stated earlier, the current 802.11n Draft 1.0 products utilize channel bonding to combine two 20MHz channels into a one wide 40MHz channel. Without proper fall-back techniques, this type of channel bonding can basically take over the entire 2.4GHz band that these products utilize. While the current 802.11n draft states that routers should not interfere with other networks in the area there are not any specifics as to how this will occur. At this time it is left up to the individual manufacturers to determine a "good neighbor" policy.
As an example our Broadcom based routers would continually blast our neighbors off the air during testing sequences if we did not manually change our channel selection. While throughput performance was best on auto settings, we typically would receive a phone call or knock on the door during unencrypted testing. We contacted Broadcom and found out that routers based on their Intensi-fi chipset will continuously scan for other networks and will drop down to single channel (channel selection varies) 20MHz as required. That sounds great until you realize the router will not change bandwidth or channels if a client is attached. Unless you notice neighboring networks on the same channel in the control panel settings you will potentially be a bad neighbor until you disconnect, change the channels manually, or hope the auto-sensing algorithm corrects the issue when you reconnect. We believe this is the main reason why the Atheros based Belkin N1 only allows mixed mode operation although we are still confirming the process they utilize.
Deras slutsats är mycket negativ:
If you require added range along with consistent throughput performance, consider the NETGEAR RangeMax 240 series of product or others featuring the third generation Airgo chipset. Although eventually this is a dead end solution, we believe the same is true of the current Draft N products as well. Even though we have not finished our testing, we have to strongly recommend that users wait if possible until 802.11n is ratified and approved.
