SmallNetBuilder

Introduction

It was last July (2007) that Zyxel first pitched me on its NBG318S combination 802.11g (actually 108 Mbps Atheros "Super G") router with built-in Homeplug AV bridge. Having experienced low interest in powerline networking articles in general, however, and with plenty to do with the restart of draft 802.11n reviews, I passed.

But when Zyxel pitched the router again in November, I changed my mind. By then, I had tested about a half dozen 802.11n Draft 2.0 routers and discovered nothing really miraculous in terms of range extension.

I had found that draft 11n routers have 3 to 3.5X the throughput of 802.11g routers with close range in the 2.4 GHz band and in their out-of-the-box 20 MHZ bandwidth mode (60 - 70 Mbps vs. 19 - 23 Mbps).

But once draft 11n products got past the "waterfall" part of their throughput vs. path loss curves, throughput dropped down to look very similar to 11g products. I also found that draft 11n products disconnected at pretty much the same signal levels as 11g products. Figure 1 illustrates this, comparing two draft 11n (WRT350N and DIR-655), one 11g (WBR-2310) and one "Super G" (DGL-4300) routers.

Figure 1: Downlink Throughput comparison, 11g, Super G and draft 11n routers

You can see that the curves all end within 3 dB of Path Loss of each other. And the Super G router even beats one of the draft 11n routers toward the end of its performance curve.

So the question I wanted to answer with the NBG318S was whether using it, and its companion PLA450 HomePlug AV Powerline Wireless Access Point, could provide better performance at my home's hard-to-reach spots than a draft 11n router and card.