We pitted the D-Link Xtreme N Duo Media Router DIR-855 against the only other true dual-band router we've reviewed, the Linksys WRT610N. The DIR-855 beat the WRT610N in overall throughput performance, but its design and desktop setup application couldn't compete. Both routers offer about the same range; the WRT610N provides slightly more coverage. Both routers are great dual-band devices; however, the D-Link costs about $60 more than the Linksys, making it difficult to recommend. Nonetheless, if you can justify the cost and need the fastest option, the D-Link DIR-855 will do the job. (For more detailed specifications, please see our specs page.)
Design and setup
Out of the box, the D-Link DIR-855 looks like a differently colored D-Link DGL-4500 . (The DIR-855 is white, while the DGL-4500 is dark blue.) The DIR-855 has three antennas attached to the back of the router--not a good design, as they crowd the network ports. The antennae are, however, removable, in case you need to install an external high-power antenna for longer range. Like most D-Link routers, the DIR-855 is wall-mountable and also comes with a vertical mount base. Similar to the DGL-4500, the DIR-855 has a top-mounted, organic light-emitting diode (OLED) Network Activity Display (ONAD) that shows more than just the network's connection status--the two navigation buttons display WAN, LAN, and wireless information via the little blue screen. However, in our tests, the screen timed out after a minute or two. The ONAD is fun to play around with at first, and is indeed useful in a number of situations, such as checking on the Internet connection, number of wireless clients, and so on, but in the long term, you might miss the regular LED status light found on most routers.
The D-Link DIR-855 includes four LAN gigabit ports and one WAN gigabit port, as well as a USB port that's designed only for Windows Connect Now technology (WCN). WCN is a feature that lets you transfer the wireless encryption key to a WCN-enabled client, such as the HP Deskjet 6840 or a Windows PC, via a USB thumb drive. This saves you from having to remember and manually enter the often cryptic encryption code. We found this feature a bit redundant, since the router also supports Wi-Fi Protected Setup (WPS), another popular method to quickly and conveniently add wireless clients to the network. Instead, we wish the USB port were for either print serving or network storage support, as in the Linksys WRT610N.
It's easy to set up the D-Link DIR-855. The router comes with a CD that contains the D-Link Router Quick Setup desktop software, which walks you though a few simple steps, including hooking up the hardware, creating an SSID, and setting up the encryption. The software, however, doesn't work if your computer has more than one wired network port, including FireWire ports. If this is the case, you will need to temporally disable ports except the one connected to the router. Alternatively, you can use the Web-based interface, which is well thought-out, responsive, and more comprehensive than the desktop application. Sadly, unlike the Linksys WRT610N, the D-Link DIR-855 doesn't come with a Mac version of its desktop setup software.
Like the name suggests, the D-Link DIR-855 comes with two Draft N 2.0 access points. One of them uses the ubiquitous 2.4Ghz frequency, while the other works in the new 5Ghz frequency; the two can run simultaneously. This is the first router from D-Link that offers true dual-band operation.
The D-Link DIR-855 offers numerous network features that you can manage via a well-organized Web interface. You can set up manual port forwarding--where you map to a specific computer in the network all the information that comes to a certain port--or use the router's preset settings for different applications and services, such as instant messengers, BitTorrent, IP phone software, virtual servers, and so on. It also offers a comprehensive set of parental control tools, including Network Filter, Access Control, Website Filter and Inbound Control. These tools allow you to control the network and limit access to the Internet by specific criteria, such as limiting Johnny's computer's access to adult Web sites, or only allowing Johnny to use instant messengers during certain periods of time. The router also lets you customize its firewall to allow some services but not others.
The DIR-855 also comes with an interesting and useful feature called Guest Zone. Guest Zone lets you create up to two separate wireless networks (one in 2.4Ghz, one in 5Ghz) to be used either by guests or the open public. Any wireless client connected to these guest networks get access to the Internet, but not your local LAN resources.
The DIR-855 gave a mixed performance in our tests. On our maximum throughput test, the router registered 101.7Mbps and 77Mbps for the 5Ghz frequency and 2.4Ghz frequency, respectively--both high, though not perfect, scores that bested the LinksysWRT610N, which came in at 101Mbps and 53.3Mbps.