Review: ZyXEL NWA-3166 Convertible 11n AP/Controller
June 25, 2010
ZyXEL's convertible 11n AP/controller provides low-cost WLAN expansion for SMBs who can't "think big" right from the start.
- Product Name, Model: ZyXEL NWA-3166 3-in-1 Hybrid AP v3.71
- Manufacturer's URL: http://www.zyxel.com
- List Price: $399
- low-cost SMB WLAN expansion
- central management cuts TCO
- built-in redundancy
- minimal centralized monitoring
- more of a central manager than real-time controller
Small office WLANs often start with just a few stand-alone APs. But, as WLAN size and complexity grows, centralized management pays off. Businesses that invest in enterprise-class managed APs can easily scale, but what about SMBs that can't "think big" right from the start?
To address this need, ZyXEL developed the NWA-3166 ($399): a 3-in-1 convertible device that can operate as an autonomous AP, managed AP, or combo controller/AP. Wi-Fi Planet took the NWA-3166 out for a spin to see how this little chameleon changes its colors.
Planning for Growth
Now that 802.11n has stabilized, AP prices are falling. Controller-managed dual-band 2x2 MIMO APs now start around $600, but still cannot be deployed without spending ~$2K on a small WLAN controller or $60-100 per AP annually for "cloud" management services.
At $399, the NWA-3166 aims for middle ground as a feature-rich AP that can operate autonomously like SOHO APs. If and when a WLAN grows enough to warrant centralized oversight, the NWA-3166 can flip into CAPWAP-managed mode, delivering controller services for itself and up to 24 other ZyXEL 3000-series APs.
To experience this transformation, we installed four ZyXEL APs: a pair of dual-band 802.11abgn NWA-3166s ($399) and two single-band 802.11bg NWA-3163s ($249). We chose APs with different radios to add policy complexity and included two NWA-3166s to exercise fail-over from primary to secondary controller. MSRP for our 4-AP WLAN: $1,296, or roughly one-third the typical cost of a comparable controller-managed SMB WLAN.
Like Cisco/Linksys, D-Link, and Netgear, ZyXEL sells both consumer and SMB APs. The NWA-3000 series is geared for small-to-medium businesses and verticals like hospitality and education that need more than consumer APs but have limited budget and on-site staff.
Under its hood, the NWA-3166 is a single-radio dual-band switchable 802.11abgn AP, using internal 2x3 MIMO antennas for data rates up to 300 Mbps. This AP connects to wired LANs using a single PoE-capable 10/100 Ethernet port. According to specs, the NWA-3166 can deliver 100-110 Mbps of throughput; our informal TCP throughput tests achieved ~85 Mbps.
Deploying the NWA-3166 stand-alone involves just slightly more than your average consumer AP. Each NWA-3166 must be initialized via console port or a statically-addressed PC. The AP then boots in single-SSID mode, advertising an open 11ng WLAN named "ZyXEL03." Which left us wondering: If you're going to require IP initialization, why not set the SSID as well?
From here, you can forge ahead or study ZyXEL's nicely illustrated 372-page user guide, which we consulted only to decode obtuse acronyms. For example, operating modes are AP, Bridge/Repeater, AP+Bridge, and MBSSID. "AP" is the stand-alone default, but "MBSSID" is required to activate up to 8 SSIDs and is the only mode for managed APs.
To activate SSIDs, you check off (and optionally reconfigure) a list of 16 factory default SSIDs. Two of those SSID configurations are fixed: a VOIP SSID "ZyXEL01" (receives preferential QoS) and a Guest SSID "ZyXEL02" (provides layer2 isolation).
Figure 1. Stand-alone AP Configuration
Finally, you must set the radio's 802.11 mode; possibilities depend on AP model. We tested "bg" and "gn" (2.4 GHz) and "a" and "an" (5 GHz) modes. Note that, as a dual-band switchable AP, the NWA-3166 supports just one of these at any given time. Data rates and MCS values can be disabled (e.g., to disallow abg clients), but you cannot disable 11b protection or operate in Greenfield mode.
When using 11n, configurable options include 40 MHz channels, short guard interval, frame aggregation, and dynamic channel selection. For example, setting width to "20/40" causes the NWA to bond your chosen channel to the one above when talking to 40 MHz-capable clients. However, when we tried 20/40 with DCS, AP Status always displayed a single 2.4 GHz channel number, even when 802.11 mode was 5 GHz! Fortunately, our APs were operating as configured; the status display was simply wrong.
Tweaking Stand-alone APs
This stand-alone set-up doesn't take long (~5-10 minutes), but must be repeated for each AP. Thus it took us half an hour to complete basic IP/SSID/radio set-up for our little test WLAN. Refining settings and applying them consistently quickly became a drag, even with just 4 APs.
The Web GUI can be used to configure security, QoS (WMM), MAC filter, layer2 isolation, per-SSID VLAN tags, and load balancing parameters. For example, the NWA-3166 supports all possible WEP/WPA/WPA2 combos, including static keys and PSKs, 802.1X, pair-wise master key caching, and pre-authentication. Small offices without a RADIUS server can even use the NWA's internal server for PEAP authentication against a local list of trusted users. But who really wants to configure the same user and password over and over again, once per AP?
Even in stand-alone mode, the NWA-3166 can load balance clients that use the same (SSID + 802.11 mode + security). Station number balancing rejects associations above a configured max, while traffic balancing rejects associations when total load exceeds 6, 13, or 20 Mbps. Idle or weak stations can optionally be disassociated when an AP becomes overloaded. According to ZyXEL, this distributed load balancing works best when AP density is high.
Figure 2. Load Balancing
However, signal strength doesn't appear to be considered before over-loading. We found that associations were distributed evenly between APs with overlapping footprints, even when all clients were much closer to one AP and would have achieved better rates there, without coming close to the configured max. Of course, in stand-alone mode, you can only see this by monitoring the individual status of each AP (managed mode illustrated above).