In our first Draft N router review we looked at units from NetGear, Linksys, and Belkin. Our review today is centered on the performance of the D-Link (DIR-625) RANGEBOOSTER N router. D-Link has been providing networking solutions for the home consumer and business user for the last twenty years. D-Link is now considered one of the global leaders in connectivity for small, medium and large enterprise business networking. They recently surpassed the one billion dollar milestone in revenue and currently employee over 1,800 personnel in 100 countries.

We discussed in detail the history of the 802.11n standards process and issues in our earlier review, but we will briefly recap the current situation and status. It has been over two and half years since the Institute of Electrical and Electronics Engineers (IEEE) formed a task group to develop and implement a new 802.11 standard for wireless local area networks (WLAN). The proposed standard is known as 802.11n and is designed to eventually offer speeds up to 600 Mbps (burst mode, quad spatial streaming in the 5GHz band) with average data transfer rates around 200 Mbps and ranges extending up to 200 Feet indoors. The current shipping Draft N products advertise speeds up to 300 Mbps (burst mode, dual channel streaming) with data transfer rates reaching 130 Mbps and indoor distances up to 150 feet, although our current test results prove otherwise.

After months of political infighting between various groups in trying to set a standard, a group called the Enhanced Wireless Consortium (EWC) was able to get the IEEE 802.11n task group to approve their specification as the proposed 802.11n standard in January of 2006. In March of 2006, the IEEE committee sent the proposal known internally as 802.11n, Draft 1.0, to it first letter ballot. The Draft 1.0 proposal failed miserably as it could not even gain a simple majority vote in favor of the proposal much less the required 75 percent majority required for ratification. Over 12,000 comments were received from various IEEE members citing standards issues, operating frequency conflicts, and an overwhelming list of concerns that include everything from power saving guidelines for handheld devices to proper streaming techniques for audio and video in media servers.

Out of the 12,000 comments about half of them have been resolved at this point through editorial content changes in the initial draft, and a significant amount of the remaining comments are duplicates. However, there are a couple of issues that are at the crux of the current controversy. The two main issues with the 802.11n, Draft 1.0, proposal that is being remedied at this time include proper Clear Channel Assessment (CCA) and power-save multi-polling standards for handheld devices.


In May of 2006, the IEEE 802.11 committee decided not to forward the Draft 1.0 proposal for a full sponsor vote and instead sent the 802.11n Task Group back to the drawing board to devise a new standard that would meet the concerns of the IEEE membership. However, the primary members of the EWC that backed the 802.11n, Draft 1.0, specification started shipping "Draft N" product into the market shortly after the proposal was sent to its first letter ballot. This has proven to be a mistake in the areas of performance and compatibility but certainly not from a sales viewpoint.

We still expect the differences to be resolved in time for a second draft to be completed this November with a letter ballot going out in January of 2007. If this is approved we can expect final ratification in late 2007. If it is not approved we estimate there will be a Draft 3.0 in the spring with final ratification in early 2008. However, the products released that meet an approved and final Draft 2.0 or 3.0 specifications are almost certain to be fully compliant with the final 802.11n amendments.

Since our first article the Wi-Fi Alliance has announced they will start certifying next-generation 802.11n wireless LAN products in the first half of next year. This industry group usually waits for the IEEE to complete a final ratification of a standard before allowing the Wi-Fi seal of approval logo to be placed on products. The Wi-Fi Alliance tests wireless LAN products for interoperability and ensures their features meet the current standard.

This same process will occur with 802.11n equipment but will be separated into two phases. In Phase 1 of the certification process, the Wi-Fi Alliance will test products shipping in the first half of 2007 for interoperability and certify them using the Draft 2.0 specification or a reasonable set of standards that are in place at that time. Products with the new Wi-Fi logo will be marked as pre-standard and should appear on retail shelves in the spring 2007 time period. Phase 2 of the certification process will use the final standard upon its completion.

Now that we've covered the history a bit, let's see how the D-Link DIR-625 performs against its competition.



Feature Set and Options: Draft N Routers

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The D-Link DIR-625 product we are testing today is based on the Atheros XSpan chipset that is also found in the Belkin N1 router. Our Linksys and NetGear products are based on the competing Broadcom Intensi-fi chipset. We will be testing other Draft N routers in the near future including the NetGear RangeMax Next Gigabit Edition (WNR854T) that sports the Marvell TopDog chipset and D-Link's RangeBooster N 650 (DIR-635) router that carries the same Atheros XSpan chipset that is in the DIR-625.

In our initial testing results we found that our Draft-N equipment at times does not interoperate with each other at full speeds or fails to connect at all due to the differing chipsets utilized by the suppliers. While we will be fully exploring this issue in our next article it is disconcerting that you can purchase different Draft N chipsets from the same vendor. NetGear offers several different RangeMax Next Wireless Routers that feature both the Broadcom Intensi-fi and Marvell's TopDog chipset. To make matters worse the RangeMax Next Gigabit Edition PC Card (WN511T) is TopDog based and our RangeMax Next PC Card (WN511B) uses the Broadcom Intensi-fi chipset technology.

While all of the routers support the vast majority of connectivity and security protocols we did find one difference that will be important to the home user expecting to use their router for streaming media or VoIP operations. All products except the NetGear unit fully support QoS (Quality of Service) technology that helps to ensure consistent streaming media and clear VoIP transmissions by prioritizing multimedia packets on the network. NetGear plans to add this capability in future firmware upgrades, and it already fully supports UPnP which enables peer-to-peer connectivity of networked computers, external storage devices, and even game consoles.

Of noted interest, the D-Link DIR-625 does not support WEP security, a feature the other products fully support. WEP security protocols are not specifically addressed in the current Draft 1.0 protocol and as such D-Link believes they are adhering to the spirit of the standard. While we no longer recommend or even use the WEP security protocol there are numerous legacy products in the marketplace that utilize WEP. If your card or other device cannot be updated to WPA security then you will need to purchase a new device in order to utilize this router.



D-Link DIR-625 - Features


The D-Link unit has the ability to be in either a horizontal or vertical position with the included stand. The unit is comprised of an attractive black and silver design although we found the black casing easily retains fingerprints. The front panel features a series of clearly labeled status LEDs that correspond to the rear panel connections. Depending upon the function of the LED, it will either blink or remain solid to indicate proper operation. Unlike our other test units, the D-Link DIR-625 ships with a wall mount kit which is actually okay as the unit's performance is not as sensitive to antenna adjustments as our other routers.


The rear panel consists of the standard connections that are labeled clearly and color coded: four 10/100 LAN ports, a WAN port, 12V power jack, reset button, and a USB 1.1 or 2.0 compatible port. This USB port supports Windows Connect Now that lets you transfer wireless settings from the router to a USB key that you can then plug into a PC or other device to activate it on the network. There are also two mounting points for the adjustable external antenna. Unlike the other MIMO based routers we have reviewed this unit does not have the standard three antenna setup and seems to suffers for it at extended distances. D-Link also offers the DIR-635 which does have a three antenna setup, though in preliminary testing it has not helped performance very much.



D-Link provides the user with an excellent documentation and setup package that rivals the consumer friendly Belkin N1 documentation. The D-Link easy installation kit is informative and lists out the basic steps to install the associated software. The installation process requires that you first install the CD, the installation wizard starts and then guides you through the process of connecting the router to your DSL or Cable modem and computer. The next process is configuring the router settings via the browser-based configuration tool. More advanced users can simply hook up the hardware and go directly to the configuration tool by entering the router's default IP address into their browser. Our neophyte network users were able to get the D-Link system up and running without any assistance. We found the D-Link configuration tool extremely easy to use as it was the most informative in our testing. The PDF based user's manual clearly explained all settings and more importantly described what each setting did in clear English.



Test Setup

With several network benchmarks available, we needed a consistent means of comparing the throughput of our test components in real world settings. We chose IXIA's IxChariot 6.30 test suite along with their Performance Endpoints software due to their industry wide acceptance for analyzing results. We install the Performance Endpoints software on each client to execute the transactions sent by the test script. This allows us to capture the performance metrics for test throughput, transaction rates, and response times. We use IxChariot's standard throughput script for our testing with TCP and UDP enabled.

We test throughput and range capability with a two-node network setup consisting of a Intel Pentium D805 based HP m7500y desktop system and a 1.83GHz Core Duo based HP DV8000T notebook. Both systems utilize Windows XP Professional SP2 and have the typical home/office application software loads. Our setup consists of an endpoint pair with the HP notebook having the PC Card wireless network adapter installed and our HP desktop system with the tested router attached to the internal LAN port. The IxChariot console is installed on our notebook and the Performance Endpoint software is installed on our desktop system. The IxChariot console is used to create, run, and monitor tests run between the endpoint pairs. Unless otherwise noted, we test the router with the manufacturer's suggested wireless PC Card to ensure accurate test results for the supplier's products.

Our throughput test results are completed at distances of 10 feet, 40 feet, 80 feet, and 120 feet. Since we believe these products will typically be sold into the home or small office environment our tests are run with the typical appliances, cordless phones, and other devices in the 2.4GHz spectrum operating as they would in a real world environment. While this test scenario is not perfect nor void of RF interference it does place the product in a real world setting where obstructions, interference, and other items can and will affect the capability of the product. Our router remains in the same room attached to the desktop pc while our notebook with the wireless adapter is positioned at specific distances from the router location.

We do not believe having the product located in an RF box, twenty feet underground, or in an empty warehouse void of internal walls is the proper environment to test products that will be located in a closet or on a desktop with clients attaching from various points within the building structure. Since our tests are performed in a true real world environment our results certainly will not match that of the manufacturer's claims or be comparable with other reviews. We firmly believe you will see better results in spacious open wall office settings, large open air buildings with a direct line of sight to the router, or facilities void of 2.4GHz traffic.

Our 10 foot test is run with the router and wireless network adapter in the same room. The 40 foot test is generated in a separate room with two gypsum walls separating the wireless adapter from the router. Our 80 foot test is run with the wireless adapter on the second floor with four gypsum walls and the second level floor separating the two components. Our 120 foot test is generated in a separate building structure on a ground floor with one brick and two gypsum walls separating the wireless adapter from the router.

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All tests are generated with the IxChariot throughput.scr test script. We run three iterations of each test at two different times during the day. We dismiss the low and high results from each test group and report the highest score from the remaining results. All results are reported in megabits per second (Mbps). Our results are based on both unencrypted and encrypted (WPA2-PSK) tests with the maximum, average, and minimum scores being reported for each distance. We will list the percentage differences between the unencrypted and encrypted results after each test section. Our notebook system will be referred to as the "Client" and our desktop system as the "Server" in our reports.



Unencrypted Throughput - Client to Server:

Our throughput test compares the performance of our D-Link DIR-625 against the three Draft N routers and the NetGear RangeMax 240 based upon Pre-N MIMO technology. This router features the proprietary third generation Airgo chipset and to date this technology has held the lead in wireless throughput and distance. Belkin has chosen not to support 802.11n or 802.11g only transmission modes so we tested the N1 router with the wireless option set to mixed n/g/b mode. In the test results we are reporting today there are not any 802.11b or 802.11g compliant devices active so the scores should be comparable. In our next series of articles we will look at true mixed mode results along with compatibility between our 802.11n Draft 1.0 devices and other wireless standards.




The NetGear WPNT834 Pre-N router has the highest throughput overall and continues to show a very consistent throughput pattern up to 120 feet. The Belkin N1 and D-Link DIR-625 excel at 40 and 80 feet in maximum throughput compared to our other Draft N routers. At 120 feet the throughput of the Atheros XSpan chipset equipped Belkin and D-Link routers fall off considerably. The NetGear WNR834B still provides the most consistent throughput across the full test spectrum of the Draft N routers.

Encrypted Throughput (WPA2-PSK) - Client to Server:




We spent an inordinate amount of time testing our routers and clients with WPA2-PSK security enabled as the test results were not always consistent or complete. After the final firmware and driver updates we were able to consistently achieve the results shown. However, at first glance you will notice that our encrypted results in the average throughput test are higher than the unencrypted results at 10 feet. We already know that 802.11n Draft 1.0 specifies WPA2 security protocol as the preferred method of encrypted transmission and it appears the hardware is optimized for it at close distances. In order to reach the throughput results we reported your network will have to be free of legacy devices and utilizing the recommended wireless adaptor for the router.

Unencrypted versus Encrypted Throughput Maximum Mbps - Percentage Difference
Client to Server	10 Feet	40 Feet	80 Feet	120 Feet
D-Link DIR-625	-18.24%	-9.94%	-6.25%	-27.03%
Belkin N1	-18.13%	-15.41%	-6.18%	-16.28%
NetGear WNR834B	-9.91%	8.29%	-14.19%	-6.58%
Linksys WRT-300N	-9.25%	-7.80%	-41.61%	-18.34%
NetGear WPNT834 (Pre-N)	-9.55%	-14.19%	-11.56%	-13.70%
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Unencrypted versus Encrypted Throughput Average Mbps - Percentage Difference
Client to Server	10 Feet	40 Feet	80 Feet	120 Feet
D-Link DIR-625	4.04%	-53.85%	-51.04%	-58.11%
Belkin N1	4.23%	-62.80%	-54.64%	-25.00%
NetGear WNR834B	4.92%	-6.74%	-25.82%	-11.81%
Linksys WRT-300N	13.17%	-18.18%	-47.35%	-10.84%
NetGear WPNT834 (Pre-N)	-1.79%	-5.36%	-5.48%	-9.15%
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While the 10 foot distance shows very little loss and actually gains for most of the routers we see an issue with the Belkin N1 and D-Link suffering an 18% loss with encryption enabled in the maximum throughput results. This is not surprising as both units are based on the same chipset. On our 40 foot test we see the D-Link DIR-625 experiencing a 53% performance hit in the average throughput numbers and 51% at 80 feet. Our Linksys router after the last firmware update still has a performance issue with WPA2-PSK enabled at the 80 foot range. Once again the NetGear WPNT834 offers the most consistent performance.



Unencrypted Throughput - Server to Client:

Our throughput test continues with the performance of our four Draft N routers against the NetGear RangeMax 240 router based upon the Pre-N MIMO technology. These series of tests measure the performance of our clients to receive information from the desktop server.




Our Belkin N1 has the best overall scores in the maximum and average throughput test results of our Draft N routers, although the D-Link router is extremely close. However, the minimum throughput of both routers remains low compared to the NetGear and Linksys offerings. The NetGear WPNT834 Pre-N router still offers the most consistent performance. Our Linksys unit suffers a severe performance drop at the 80 foot range and after reviewing the test script results we noticed the Linksys had very sporadic connection rates. Although we never lost a signal it was obvious that the Linksys was having severe communication issues at this distance.

Encrypted Throughput (WPA2-PSK) - Server to Client:




The NetGear WPNT834 Pre-N router has the highest throughput overall with results almost doubling the capability of the other routers in the average results test at the 80 and 120 foot ranges. The NetGear WNR834B once again provides the most consistent throughput of the Draft N routers in the encrypted tests. We actually see the D-Link router performing better overall than the Belkin unit up to the 120 foot range. The Linksys WRT-300N posts the worst overall results when encryption is turned on.

Unencrypted versus Encrypted Throughput Maximum Mbps - Percentage Difference
Client to Server	10 Feet	40 Feet	80 Feet	120 Feet
D-Link DIR-625	-18.00%	-8.48%	-34.60%	-18.45%
Belkin N1	-20.88%	-12.26%	-31.25%	-21.48%
NetGear WNR834B	-7.80%	0.00%	-4.67%	-14.65%
Linksys WRT-300N	-13.33%	-33.40%	68.60%	-14.06%
NetGear WPNT834 (Pre-N)	-16.73%	-12.18%	-13.54%	-12.55%
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Unencrypted versus Encrypted Throughput Average Mbps - Percentage Difference
Client to Server	10 Feet	40 Feet	80 Feet	120 Feet
D-Link DIR-625	-37.40%	-64.25%	-55.68%	-25.64%
Belkin N1	-40.43%	-65.70%	-57.74%	-31.88%
NetGear WNR834B	-9.07%	10.03%	-25.28%	-27.40%
Linksys WRT-300N	-55.92%	-54.97%	-31.58%	-24.14%
NetGear WPNT834 (Pre-N)	-13.63%	-9.85%	-9.03%	-8.04%
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Once again we see the Belkin, D-Link, and Linksys units struggling with encryption enabled in the majority of our 40 foot and above distance tests. It appears the current NetGear firmware and driver implementation is simply optimized better than our other Draft N routers. The NetGear WNR834B actually shows zero loss and up to a 10% improvement at the 40 foot range.



Quick Thoughts

Our original opinions about the Draft N products still stand. While the 10 and 40 foot throughput numbers are fairly impressive they do not live up to the marketing hype. Overall, the routers do not offer enough of an advantage over the current Pre-N MIMO products to warrant an upgrade. While the Pre-N Airgo based products contain proprietary technology and will never be upgradeable to 802.11n, they perform just as well or better than the current Draft N products whose manufacturers also cannot guarantee full compatibility with the eventual 802.11n standard.

We will complete the testing of additional Draft N routers from Buffalo, NetGear, and D-Link in the near future but do not expect to see any true differences in performance. We understand from NetGear their Marvell TopDog chipset products will have better overall throughput than their Broadcom Intensi-fi chipset based products but we doubt it is enough to make a real difference. Even though we have not finished our testing, we have to strongly recommend that users wait until 802.11n is ratified and approved.

However, for those users willing to take the Draft N plunge we would suggest getting the D-Link DIR-625 or Belkin N1 routers (along with the matching adaptor cards) based upon the Atheros XSpan chipset for distances under 80 feet. This is not entirely based upon absolute performance criteria although both routers had very consistent maximum and average throughput rates up to 80 feet. Instead, this is based on the user experience with both routers. The packaging, documentation, router management tools, and ease of use characteristics with both routers were exemplary for first time users while still providing information that advanced users would find beneficiary. Also, these two routers did not suffer the same "bad neighbor" effect we witnessed in our original testing of the Broadcom Intensi-fi equipped Linksys and NetGear Draft N routers. Overall, we would give the nod to Belkin for superior customer service but still stand by our recommendation to wait on the final 802.11n standard.