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Introduction
| At a Glance | |
|---|---|
| Product | D-Link Xtreme N Duo Wireless Media Router (DIR-855) |
| Summary | Dual-band dual radio 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 speed • High simultaneous sessions • Automatic QoS for Internet uplink and WLAN |
| Cons | • Expensive • Lacks of matching adapter holds back performance |
Finally, the review that dual-band draft 11n fanboys and girls have been waiting for: D-Link's DIR-855. Since the 855 uses the same main board as its DGL-4500 dual-band single-radio sibling, please go over to that review if you need details on the 855's feature set. I'm going to cover only the differences here—which are in the wireless configuration—and concentrate on how it performed.
Hardware Differences
As I've said before, the 855 is the DGL-4500 loaded up with two radio boards instead of one. So it has the same OLED front panel, same rear panel connectors and same feature set. The only difference is that the 855's case and antennas are white, to better appeal to homebodies (vs. black for gamers).
Unlike the Linksys WRT350N [reviewed] and WRT600N [reviewed], the USB port on the back isn't used to attach a drive for sharing a USB drive or printer to your LAN. It's just there to support the flash-key based Windows Connect Now (WCN) auto-configuration method. Note that all three antennas use RP-SMA connectors for easy upgrade, if you can find dual-band antennas!
Figure 1 shows the 855's main board and Figure 2, the 4500's. There actually is a difference, hidden under one of the 855's heatsinks. The 855 uses a Ubicom IP5170, clocked at 350 MHz, while the 4500 uses a Ubicom IP5160, clocked at 275 MHz. You'll see the difference that this makes in routing throughput shortly.
Figure 1: DIR-855 main board
The gigabit switch however, is a Realtek RTL8356, instead of the Vitesse VSC7385 used on the DIR-655. The Realtek switch chip supports up to 9K jumbo frames, and I found that it handled 4K jumbo frames just fine. D-Link still doesn't spec jumbo frame support.
Figure 2: DGL-4500 main board
Although both radios use Atheros XSPAN chipsets, they are not the same board. The 2.4 GHz radio (Figure 3) uses the Atheros XSPAN AR5008 chipset, with AR5416 Baseband/MAC and AR2133 3 Tx, 3 Rx, single-band 2.4 GHz chips.
Figure 3: 2.4 GHz radio board
The 5 GHz radio (Figure 4) is the same one used on the DGL-4500. It uses the same AR5416 Baseband/MAC, but the AR5133 3 Tx, 3 Rx, dual-band 2.4/5GHz radio, instead of the AR2133.
Figure 4: 5 GHz radio board
Note: The 855 hardware is now on its second revision (A2), which, according to D-Link, will be the flavor that hits retail late this month. My review unit was the original A1, since D-Link didn't have any A2's on hand.As near as I can tell from the FCC ID pictures, the difference is that the A2 radios use newer Atheros AR9001AP-3NX2 chipsets. Both radio boards use an AR9160 two dual-band 3x3 MIMO MAC/Baseband chip. The 2.4 GHz radio board uses an AR9103 3T3R 2.4 GHz radio and the 5 GHz board uses an AR9106 2.4/5 GHz 3T3R radio.
User reviews
Average user rating from: 2 user(s)
Pricey, but well engineered, fast, stable, reliable. A notch above.
I've used wireless routers from Netgear (an 802.11g model, and an 802.11n model), from Linksys (WRT600N - 802.11n simultaneous dual mode), and now the D-Link DIR-855. My experience with this model is that it provides a level of stability that I had forgotten could exist. I had grown so accustomed to power-cycling my routers that it actually seemed like something was missing when I realized I hadn't needed to do so with this one in some time.
If you think a router is a router, and wireless-N is wireless-N, you'll probably skip this router because of its price. That's a shame, because its better-than-standard engineering is not going to be appreciated simply by looking at a box on a shelf at the electronics store. Its routing is indeed very fast. It does support jumbo frames where most home routers don't. It manages to go on for extended periods of time without needing to be reset or restarted. It has a rich feature set. And its dual-band simultaneous-use wifi radios are a feature that really ought to become standard.
The marketing for this router suggests using the 5GHz radio band for media streaming, and the 2.4GHz band for general computing. But there's another strategy that I like better: Use the 5GHz band for pure 'N' devices, and the 2.4GHz band for mixed-mode applications. I put my laptops on the 5GHz band, and my WiFi Blackberry, my wife's Iphone, as well as house guests on the 2.4GHz band. That keeps the 5GHz band pure, which allows it to run full speed. The 2.4GHz band I have configured to mixed g/n mode, which incurs a performance penalty. In this way I keep the high performance stuff on one band, and the low performance stuff on the other band.
This approach works best if devices such as BluRay player, media streamer, etc., are hard-wired rather than via WiFi.
Areas for possible improvement in future versions: It's getting to be about time that we start seeing five LAN ports, not four. Make Jumbo Frame support official. Make the USB storage option more like a true NAS link (don't require software to be installed on client computers, and do offer WAN-side FTP/Web access with password protection, of course).
Expensive - Unstable - Unreliable
Having very little knowledge about routers seeing as i had never owned one before i decided it would have been a good start by buying the top of the line product from a well known company. D-link was a company i had heard about and therefore i choose the DIR-855, but only after i had read reviews from various magazines that said it was a fantastic feature packed router!
Unfortunatly the router was sub par. My goal was to have all my movies on my desktop machine in the study and then stream them over the wifi to my laptop in the lounge room (which was connected to the TV). It worked for maybe a few weeks before i started to have problems with it. The signal would drop out, It would power its self off and then wouldn't turn back on again. It was all bad!
I then went onto the D-links DIR-855 forum looking for answers, but that forum was neither moderated nor used. Adding to the pain was that firmware updates for the device were almost non existent and when a new firmware was released the Update feature on the router didn't know it was there forcing me to do my own homework and a manual update.
After that i sent the router in for an RMA and recieved a router in return that was wore than the one i sent in. After telling D-link about the problem they said i should update the firmware and ther was nothing more they could do. So i threw it in the bin!
I suppose routers are a little hit and miss these days seeing as you can find a router with bad reviews, but with users who swear it's the best router ever. So i have now ordered an Asus RT-N16 which seems to be quite stable so i'm hoping i have a better experience with it.
The DIR-855 was the last D-link product i will buy until they get their act together. A $350 router should be a damn good router!
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