by September 6, 2005 0 comments



Wireless and wireless access points have come a long way since May 2004, when PCQuest last visited the scene. At that time, we sifted through thirteen of them-8 of these were still 802.11b, while a mere 5 promised 802.11g. This time, a number of things have changed from last year. Many features that were new then have become standard in every access point today. Or, they have been rendered obsolete because of the trans-migration from ‘b’ to ‘g’. In their stead, new vistas have emerged and promise to hold on for a while. We also take a look at these features and issues.

This time, we’ve split the wireless access points into two categories-SOHO and
enterprise. The difference between the two was quite apparent. Wherever it wasn’t, we decided based on the features. Out of the 15, five classified as enterprise access points. So what should you look for when going for a wireless access point? And how differently should you evaluate them when selecting them for an enterprise or a SOHO need?

Clustering & fail over
Access points have the ability to organize themselves into clusters and provide fail-safe access and routing. Enterprise APs need this more than anything, mainly because of the number of them that would be deployed, as well as the complexity (multiple floors, etc) of their deployment. For a SOHO, this would obviously not be a concern.

Intelligent access points have the capability to determine if they are choking under a large number of connections or usage. These APs can then transfer their load to other routers or APs before things become too hot to handle. You can configure the limit at which this handover happens. This can be based on the number of connecting users or the load on the bandwidth.

Virtual LANs
VLANs allow you to do two things-segregate your users into different virtual networks for better security, as well as separate your internal users from roaming and guest users and minimize malicious vector paths. Enterprise APs should have this ability. It is also excellent if these APs can go on each VLAN under a different MAC/SSID, with different security keys (WEP/WPA) for maximum security. This feature is also not present in most SOHO routers. If anything, it’s present as a proprietary implementation in some
APs. 

Isolation
APs can deal with isolation in two ways-they can be isolated themselves or they can isolate each client. Station isolation will result in connection refusals to any client. Only APs will be able to connect and this can be used to setup a bridge of APs through an existing wireless field without running the risk of network contamination from clients logging on accidentally or purposefully. Clients can be isolated from each other for maximum security-like in a conference room during a board meeting. Enterprise APs should offer both forms, while client isolation would be a sufficient optional for a SOHO equipment.

Quality of Service
QoS deals with the quality of bandwidth and service offered to connecting clients. This can be managed by the AP as well as the client’s network software. When APs can manage QoS, they end up offering the most optimal throughputs under the circumstances and results in a better overall network performance. A must for enterprise networks and a good optional for the
SOHO.

Wireless Distribution System
WDS allows administrators to create a network of wireless-only devices and route between them. It switches off all wired connections. It could be a good option for places where you don’t have a wired network. WDS connects APs and clients and other devices (like printers and mobile devices) with each other. If your network has a fairly reasonable number of wireless devices, then this might be a good feature to have. Look for it in an enterprise AP, atleast from a future-expansion perspective. Not really needed for the
SOHO.

Security revisited
AP vendors have started looking at WPA seriously. A number of APs that we received even boasted of ready-support for RADIUS and other authentication mechanisms. Simply check if your desired AP has EAP-TLS or EAP-TTLS in its feature set. MAC-based address filtering is essential if you want to keep unwanted outsiders out of your network. While 128-bit WEP might be strong enough for a SOHO network, you would need to go in for a RADIUS capable AP in a medium to large enterprise.

Not just a wireless plug
APs have since long ceased to be just a wireless plug that clients can connect to for network access. They can act as AP-AP bridges, repeaters and gateways to various services just to name a few. The more the number of modes that your AP supports, the better. This is good for both market segments we evaluated for.

Higher bandwidth 
Atleast three access points in this shootout support a theoretical maximum bandwidth higher than 54 Mbps. The maximum we saw labeled was 125 Mbps. This is promised through a variety of mechanisms. While Buffalo calls it MIMO, Belkin and D-Link call it a high-speed mode of their regular 54 Mbps products.

Whatever the name, they promise faster overall improvements in throughput in mixed (b and g) environs and a much faster performance in pure high-speed or MIMO surroundings. Of course, in order to take advantage of the enhanced throughputs, you will need to be using their proprietary adapter at the wireless terminals.

MIMO stands for Multiple In Multiple Out. Basically, this is wireless equipment that has more than one transmission and reception channel. This allows the equipment to have more simultaneous communications active, supposedly improving throughput. The MIMO AP we received (Buffalo AirStation WZR-G108) is rated at a theoretical 108 Mbps. This technology is also supposed to give you better performance where there is high interference from other wireless networks, and a much larger range.

Management
The price tag and the performance alone should not be the basis of a purchase. Wireless networks are far more prone to intrusion than wired ones, because it is no longer necessary for the intruder to be physically in your space. Now, intruders need not be malicious users or even hackers. They can simply be your own colleagues who should not really be on this wireless network. Or, they can be innocent passers by whose computers decided yours was a stronger network to connect to. The only way to monitor and protect your network is from the AP itself. Most enterprise-class access points will support SNMP or better the Spanning Tree Protocol (STP). SNMP allows your network monitoring software to pick up data and give you control on the device. The logs on the point will give you a historical record of events and troubleshoot problems. The more the management features, the better.

Features-what else?
What are other things you should look for while selecting the right access point? If you need higher range or signal boosting, will your AP support a high-gain antenna? What sort of software ships with the equipment, what does it allow you to do? If you need to place APs in areas where drawing a power line is difficult, does your AP support Power over Ethernet? 
Access points are generally better placed high up near the roof so that signals from them bypass most obstacles. Is your AP friendly towards such a deployment (placement of LEDs, size and shape, orientation of antenna)? Are the antennae on your AP configurable, and to what extent?

On enterprise APs, look for the level and types of logging it allows. Look for this
especially in an enterprise product. On SOHO routers and APs, you should also look for: broadband routing, content filtering, virtual server support and firewall capability. Although, the firewall option is a good idea for the enterprise too.

The performance question
We measured the performance of these access points in three different ways. We used NetIQ’s Qcheck benchmark for checking the raw TCP/IP throughput and for data streaming (UDP). The third test was a live file transfer over the network. Details of each are given below:

Throughput
Some APs shipped to us with their own Cardbus (PCMCIA) adapter. We tested these access points with these adapters as well as a standard 54 Mbps adapter. To check the operation of the high-speed and MIMO devices, we checked with their provided adapters. This gave us two scores for those devices — where we placed more emphasis on the device if it delivered better results with its higher-speed promise.

File transfer
We spend much of our online times transferring data and files over the wireless network-the primary purpose of the 
network for most of us. These maybe files you’re moving to colleagues, or even e-mail. We packed some 170 MB of different sized files-some large some small -into a folder and copied the entire lot across to another system, over the wireless link. We did this test twice-once with the proprietary adapter if they shipped us one, and another with our standard.

Streaming
This was a simple UDP stream of data, setup by QCheck. This test checks if packets are dropped in transit and effective stream speed. Streaming is essential for bandwidth intensive multimedia applications, like VoIP, video/audio streaming and broadcast presentations.

Setup and review notes
We used an IBM Thinkpad R51 notebook with all its other networking disabled. We then used the Cardbus adapters (either supplied with the AP or a common Linksys WPC54G). The OS was Win XP SP2. DHCP and automatic channel selection were
disabled, speed was set to the maximum available and DRS (Dynamic Rate Shift) was disabled for the NetIQ test. The notebook and each AP were kept at a fixed distance apart.

Lastly, price and warranty are of course important, especially for enterprise class APs. SOHO models are available at fairly low prices and their price differential isn’t too much. However, the prices for enterprise APs vary drastically across different brands, so choose your options carefully. 

[We no longer carry the specs table for products that come for shootouts in the
magazine. Instead, we post it on our forum. You can download it from forums.pcquest.com, from the “Shootout Tables” board.]

Sujay V. Sarma

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