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A wireless access point extends your wired LAN to wireless users, but this access point from D-Link does much more than that. The device can provide five

functionalities. The first is the most basic one, that of an access point.

Second, it can work as a wireless repeater to increase the range of your

wireless network. Third, as a wireless bridge between two different wireless

networks. Fourth, as a multi-point wireless bridge between more than two

different wireless networks. And, fifth, in wireless client mode wherein it

works as a client of some other wireless network. But, you can use only one of

these functions at a time.


When working as an access point, it has an enhanced mode of operation wherein if it's used in conjunction with other enhanced D-Link wireless products, it will work at double the speed of regular 802.11b products, ie 22 Mbps (other 802.11b products work at 11 Mbps only).

All the above-mentioned features are also present in the device's younger cousin,

D-Link DWL-900AP+. However, D-Link DWL-1000AP+ differs by offering load

balancing and redundancy features. It can be used with other DWL-1000AP+

devices to create a load balanced wireless network. In this, all access points

will share the wireless traffic amongst themselves as the number of wireless

users increase. This way a particular access point will not run out of

bandwidth once the wireless user base in your organization grows beyond a

single device's capability. Redundancy feature works such that it can be used

as a backup access point for another DWL-1000AP+. So if the primary access

point fails, the second one will take over. The backup and primary access

points connect to each other via an additional Ethernet link provided on the

devices. These features can be useful when implementing a wireless network in a

large enterprise.

Coming to performance, we tested the throughput (raw data transfer rate), response time and streaming data rate between a wireless client and wired host, with the access point working as the communication link between the two. The wireless

client was a laptop containing an internal mini-PCI 802.11b card. We also

tested the access point with a D-Link 650+ Air Plus 802.11b PCMCIA card to

check the enhanced wireless mode, which promises to double the transfer rate.

The wired client was connected to the access point via a 100 Mbps switch. We

used NeIQ Endpoint, Ixia Chariot Console, and NetIQ Qcheck for the tests. We

tested at two wireless signal strength levels. First, at high signal strength,

which was between 90-100%, and then at low signal strength, which was between

15-20%. Low signal strength obviously yielded lower performance as compared to

high signal. The high signal strength was done keeping the clients in line of

sight of the access point, while there were obstructions in the low signal



With a non D-Link wireless card, at high signal strength, the maximum and average

throughputs achieved were 5 Mbps and 4.3 Mbps, respectively. With the D-Link

Air Plus card these increased to 7.6 Mbps and 7.0 Mbps, respectively. So, while

you would expect to achieve the theoretically possible transfer rates, in real

world usage, what you get is much less. But still the D-Link wireless card

managed a 50% improvement over the normal card, which can be attributed to the

enhanced mode of operation available in some D-Link products.

Next, comes the response time which measures the latency in the network. The average response time between the wireless laptop and wired desktop was 3 millisecs, which is fairly good. It even improved to 2 millisecs with the D-Link wireless

card. Finally, we have the streaming test, which checks the network's ability to

transfer a continuous stream of data at a particular rate. This is useful for

applications such as video conferencing and audio and video streaming. In the

UDP streaming test, the maximum achieved streaming data rate was 490 kbps,

which is also on the lower side but good enough for most streaming

applications. With the D-Link card it went up to 590 kbps.

After this we moved the laptop away from the aAccess point to a distance where the signal strength dropped to 15-20%. With the regular wireless card, the maximum and average throughputs achieved here were 0.983 Mbps and 0.360 Mbps. So the data

transfer rate decreased significantly with the decrease in the signal strength.

The response time also increased to move between 20-25 millisecs, which means

increased latency in the network. The maximum streaming rate here was 246 kbps,

which surprisingly is not very bad. Overall, an access point with features

suitable for enterprise needs and is also priced well.

Anoop Mangla

source: PCQuest