How to chose the best Access Point (AP)

Today the market is flooded with a range of wireless access points. There are dozens of important features to consider, so much variation in cost and several different performance parameters, that it can become quite confusing to decide which one is right for you. To address most of these concerns, we ripped apart 13 wireless access points with a barrage of tests, and analyzed them for over a dozen features. You'll find their individual reviews in the subsequent pages, followed by a table comparing the important features as well as the performance results. These include eight access points of 802.11b and five of 802.11g standards. But, before that, we'll look at the important features that should be considered when buying an access point, followed by the performance parameters. All performance and features parameters discussed here, along with the price and warranty of each access point, have been included in our analysis for the shootout. As usual, we used the Brown-Gibson model to arrive at the weightages for these parameters.

Which standard?
Speaking of standards, it's still not legal to use 802.11g-based products without a license. Only 802.11b based ones can be used indoors freely. While it's not very expensive to obtain a license, it's a long drawn process. Alternatively, you could go for an 802.11b access point that's upgradable to the g standard, apply for a license and then upgrade once you get the license. It's, therefore, an important feature to consider when going for an 802.11b access point. If you have a license or don't mind putting in the effort to get one, then you could also go for 802.11g based access points as they have a maximum throughput capability of 54 Mbps, unlike 802.11b that can deliver only 11 Mbps. Plus, the g standard is backward compatible with b, so even if you have b based wireless clients, they would still work, albeit at 11 Mbps.

How much security?
Security has always been a concern in wireless networks, so it's important to check out the security features of an access point before you buy it. First, define the level of security you need in your setup. For instance, if your office is in a crowded area and the chances of your WiFi signal going out of your premise is high, then it's better to go for tighter security because it would be easy for someone from outside to misuse your WiFi network. What level of accessibility are you planning to provide through your WiFi network to your mobile users? Is it just to surf the Net or will they also be able to access your servers? There are various security modes providing different levels of protection. The most basic is WEP (Wireless Equivalent Privacy) encryption, which is present by default in all access points. But, Wireless Equivalent Privacy has been found to be weak and, therefore, not always suitable for security a WiFi network. Look for other security modes, such as MAC-address based filtering, Radius-based authentication and WPA before you go out on your hunt for the right access point.

Modes of operation
Most access points can be used in more ways than one, but this functionality varies across vendors. Besides working as a standard access point, it can also work as an access point-to-access point bridge, repeater, gateway and more . Having more modes of operation gives an organization the flexibility to use the access point in any way they need. So, support for more modes is always better.

Management features
How easy is it for you to manage your access point? Most of them provide a Web-based interface for management, but that's not enough. Look for more management features available in this interface. Does it support SNMP, so that if you have your network management software running in your organization, it can easily be added in? Is it simple support for SNMP or can you also set traps for certain conditions so it sends out information to the administrator every time there's a problem? What other information can the access point provide? Does it maintain log files of all system activity? What level of activity can it put in the log file? What kind of statistics can it display about itself? The more management features it has, the easier it will be on the network administrator.

Load balancing and fault tolerance
If the number of users connecting to a particular access point with load-balancing support increases beyond a predefined limit, it will shift some users to a nearby access point. This feature can be useful if you have high user density per access point. So, look for one that supports load balancing. Fault tolerance, of course, means that if one access point goes down due to some reason, then the clients connecting to it should be diverted to another access point.

Other features
There are several other features that need to be considered. One is automatic channel selection, which becomes important if you're deploying lots of access points. This way the administrator doesn't have to manually define each channel, thereby reducing chances of human error. Can the antenna of the access point be upgraded to a different type or of higher power? What kind of software ships with the access point? How useful is it when deploying WiFi? Does the access point support power over Ethernet? This can be useful if you're placing an access point where you don't have a power connection nearby.

What about the quality of the power adapter itself? We noticed that several access points still shipped with the bulky transformer-based adapters. Today, most devices come with the lightweight, SMPS-based adapters, which have a longer life because they consume lesser power and generate lesser heat. So, an SMPS-based adapter is always preferable over transformer based one.

Performance parameters
There are a number of parameters that we considered for performance. For measuring all data transfers, we used NetIQ's Qcheck benchmark. The tests are as follows:

Max range: What's the maximum distance that a client can go from an access point without loosing connectivity and also be able to transfer data? While doing this test, we ensured there were no obstructions between the access point and the client. We stopped measuring beyond 200 mtrs as only a few Access Points showed connectivity beyond that distance.

Max range with max signal strength: While the signal strength of an access point reduces with distance, up till what distance can an access point keep it in excellent condition? The higher this is, the better.Here again we stopped measuring beyond 150 mtrs for same reasons as above.

Max throughput: For clients connected in close vicinity to the access point, what's the maximum throughput that it can offer? Surely, it's impossible to obtain 11 and 54 Mbps, the maximum theoretical limits of 802.11b and g standards, respectively. So, we measured the maximum that each access point could provide with a client when:

*It used a WiFi card from the same vendor.
*It used a third-party WiFi card. Most laptops shipping today are Centrino based, which means that they use an Intel WiFi card. For this test, we used a Centrino-based laptop.

Latency: We measured the average latency between the client and the access point while transferring some data. Here, lower latency is better.

Throughput with streaming data: This becomes important when you're using WiFi for applications that require a constant stream of data without any break., like voice and video apps. For this, we configured the test to maintain 1000 Kbps for 15 seconds.

Resistance to interference: The 2.4 GHz frequency band that's used by all these access points is susceptible to interference from other devices like cordless phones and Bluetooth. We checked how susceptible was an Access Point to such interference by measuring the throughput with a Bluetooth device in between.

A few tips Finally, here are a few tips to keep in mind.

*Please check that the features mentioned on the packaging of your access point are actually there. In one access point we found the packaging said 256 bit WEP encryption, while it actually only supported 128.
*Before setting up an access point, read the instructions carefully. Some access points provide a MAC address that has to be entered during the installation.
*Place the access point where there's minimum interference from other devices. Usually, it's advisable to place it near the ceiling.
*Many access points specify how to position their antennas, so please check the manuals for that. Don't tamper with the antenna when it's working.
*Coexistence of 802.11g and 802.11b wireless clients on the same wireless network could slow down your network performance. So, when upgrading to 802.11g, also try to shift your clients to the same.

Lastly, there's a wide price variation that we found in all the access points, ranging from Rs 8,000 to Rs 52,000. So, choose carefully, depending upon the features you want.

resource : pcquest.ciol.com