Wireless Reviews

Introduction

At a Glance
Product	D-Link Xtreme N Dual Band Gigabit Router (DIR-825)
Summary	Dual-band dual radio dual antenna Wi-Fi Certified 802.11n Draft 2.0 router based on Atheros XSPAN silicon
Pros	• Two radios for simultaneous dual-band operation • Gigabit WAN and LAN with > 300 Mbps routing spee • High simultaneous sessions • Automatic QoS for Internet uplink and WLAN • USB server for storage and printers
Cons	• Unimpressive range, particularly 5 GHz

D-Link has apparently decided to take another run at making a two radio, dual-band draft 802.11n router, given all the negative baggage that its late-to-the-market, expensive, still hard-to-find and poor-performing DIR-855 has acquired. The good news is that you can actually find the DIR-825. The bad is that its performance, particularly in the 5 GHz band, will probably cause many of them to go right back to the store.

What It Is

The 825 uses the same basic design that first appeared in the DGL-4500, i.e. Ubicom CPU, two mini-PCI board Atheros XSPAN radios and a four port gigabit switch. In fact, if you look at the larger version of Figure 1, you can see labeling in the lower left corner for the DIR-855, DIR-655, DIR-660 and DGL-4500. Note the heatsink on the gigabit switch and thermal pad on the Ubicom processor.

Figure 1: DIR-825 inside view

I already detailed the differences in between the 855 and 825 in this article. They boil down to using a Realtek RTL8366SR gigabit switch, instead of the Realtek RTL8356 in the 855 (both support up to 9k jumbo frames) and radios using Atheros' newer XSPAN AR9100 chipsets vs. the AR5008 chipsets in the 855. Both products are powered by a Ubicom IP5170U clocked at 350 MHz.

You might notice that D-Link has used the 855's case, with an empty middle hole for a third antenna. The photo also shows that the mini-PCI radios even have all three miniature connectors loaded. But if you want to try to turn an 825 into an 855, forget it. All the components required to combine the 2.4 and 5 GHz radio outputs aren't loaded. And you'd have to scare up an additional dual-band antenna, too.

I tested the 825 using the B1 hardware version of D-Link's Xtreme N Dual Band USB Adapter. The A1 version uses an Atheros AR9170 MAC/BB and AR9104 Dual-band 2x2 MIMO radio and, if you'll remember, delivered very poor performance when I tried it with the DIR-855. The B1 version shown in the not-so-great FCC photo in Figure 2 uses a Ralink RT2870F BB/MAC and RT2850L 2.4/5GHz 2T3R Transceiver.

Figure 2: D-Link DWA-160 B1 USB adapter board

Features

Modes and channels are the same as the 855, but I'll repeat the information here for your convenience. Channels in the 5 GHz Lower (36, 40, 44, 48) and Upper (149, 153, 157, 161, 165) bands are available, whether or not you choose the Auto Channel Scan Wireless Channel option.

The 802.11 Mode selector provides just about all the options you would need to solve compatibility problems with "legacy" 802.11b/g clients. For 2.4 GHz you get:

• Mixed 802.11n, 802.11g and 802.11b (default)
• Mixed 802.11n and 802.11g
• Mixed 802.11n and 802.11b
• Mixed 802.11g and 802.11b
• 802.11n only
• 802.11g only
• 802.11b only

and for 5 GHz you get:

• Mixed 802.11n and 802.11a (default)
• 802.11n only
• 802.11a only

The Basic Wireless settings screen also provides access to Wireless Security settings, which include a full suite of WEP, WPA and WPA2 settings, with both "Personal" (PSK) and "Enterprise" (RADIUS) WPA/WPA2 modes. Security can be set separately for each radio.

I did a quick WPS pushbutton session check with the Ralink-based B1 version of D-Link's DWA-160 Xtreme N Dual Band USB Adapter —D-Link's only dual-band adapter. I reset the router to defaults to ensure that there were no settings that could prevent a successful WPS push-button session. Unfortunately, after multiple attempts, I could not get a connection via the WPS session.

Advanced Wireless controls are the same as the 855's and include High / Medium / Low transmit power and WLAN partitioning.