Up to 1.67Gbps 802.11ac with upcoming client adapters
Fifteen years ago, Linksys introduced a black-and-blue wireless router that became the first 802.11g draft product to hit the market. The WRT54G offered consumers reasonable performance, exceptional versatility with custom firmware, and fell dramatically in price in the following years.
Brief history of WRT series
With the Linksys WRT54G, the company achieved a goal of offering Wireless G hardware as the natural progression from Wireless B, just as 100BaseTx was the progression from 10BaseTx for Ethernet. In 2003, the company was then acquired by Cisco, which continued to market its networking gear as “Linksys by Cisco” all throughout the 802.11n wireless era that followed ahead. By March 2013, the company was again sold to Belkin, which oversaw the rollout of its first 802.11ac wireless products and continues to market them based on revisions to the current wireless networking protocol.
Back in April 2014, the company unveiled the WRT1900AC, its first 802.11ac wireless router and successor to the legendary WRT54G introduced 11 years prior. The device’s overall design was very much inspired by the classic black and blue color scheme, but brought WRT series back with a sleek starship design using four external antennas instead of two. The WRT1900AC also featured a more robust 1.2GHz dual-core ARM processor, 128MB of flash memory, and 256MB of DDR3 RAM. Aside from the obvious migration from 54Mbps speeds on a single 2.4GHz band to 1.3Gbps on 5GHz using three spatial streams (3x3), the router also brought back excitement to the open-source community with its support for custom DD-WRT and Open-WRT firmware projects. Priced at $137, the company’s first dual-band open source 802.11ac router offers a competitive feature set, but has been eclipsed by a more recent jack of all trades.
The company has since offered a more cost-effective counterpart, the WRT1200AC, which debuted at CES 2015 and is now available for $99. The midrange option goes back to using two antennas, yet delivers 867Mbps on the 5GHz band using two transmit and two receive spatial (2x2) streams. Just like its tri-stream counterpart, it also supports custom firmware using DD-WRT and OpenWRT.
Linksys WRT3200ACM with MU-MIMO
Linksys’ current WRT series performance router, the WRT3200ACM, has taken all of the attributes and characteristics of its WRT1900AC predecessor and now offers newly introduced 802.11ac features. Introduced in October 2016, the router includes triple stream (3x3) 160MHz bandwidth on the 5GHz band, and offers 867Mbps on each individual stream for a peak 2.6Gbps throughput. This is a two-fold increase from three 80MHz streams, which offered 433Mbps on each individual stream for 1.3Gbps peak throughput. Using a recent Dynamic frequency selection (DFS) certification from the FCC, Linksys is also able to triple the channels available at 80MHz to prevent additional interference with other Wi-Fi broadcasting devices in the vicinity for a clearer signal.
Yet more importantly, Linksys has introduced a key 802.11ac Wave 2 (late 2013) technology called MU-MIMO, which builds upon key broadcasting components such as spatial multiplexing, beamforming and packet scheduling algorithms found in many high-performance routers. Since 2007, 802.11n draft routers have supported single-user multiple-input and multiple-output (SU-MIMO) technology. Depending on the number of streams supported, this allowed Wi-Fi routers to transmit one to three streams, and receive one to three streams, but the routers could only communicate with one device at a time. This results in a backlog of scheduled packets that are sent to each connected device one by one (but not necessarily chronological order), rather than distributed all at once.
With the upgrade to multi-user, multiple-input and multiple-output (MU-MIMO) technology, a wireless router like the WRT3200ACM can now transmit and receive data from multiple devices at the same time. Of course, each connected device is also required to support MU-MIMO for this to work. But according to experts, even non-MIMO devices (and SU-MIMO devices) will get indirect performance improvements as a result of any MU-MIMO devices being served more quickly. The other core benefit gained with multi-user MIMO technology is that the beamforming methods included within 802.11ac are much more widely adopted in products across various manufacturers. This prevents a situation that arose with 802.11n routers using SU-MIMO, where some client devices did not support the same beamforming methods. These routers also required client devices to have multiple antennas to send and receive SU-MIMO streams. This required extra signal processing, particularly in mobile devices where power consumption is of particular importance.
Why is this marketed as a 3200Mbps device?
One of the first questions many prospective consumers have asked about 802.11n and 802.11ac routers are related to theoretical speeds and those listed on the product box. The WRT3200ACM is no exception, as Linksys is advertising a maximum 2600Mbps throughput on the 5GHz band, yet a 3200Mbps number in the model name. Here, just like many wireless vendors, the company has simply added the total maximum throughput that the router can transmit over both 2.4GHz and 5GHz bands, or 600Mbps and 2.6Gbps, respectively. On the lower band, this is accomplished using three spatial streams at 200Mbps each, while the 5GHz band (802.11ac only) uses three spatial streams at 867Mbps each.
But alas, this point is mentioned on the side of the retail packaging rather than the front.
The Linksys WRT3200ACM MU-MIMO high performance router is packaged in a rectangular white box featuring the name “WRT” in a colored gloss finish, along with an image of the behemoth itself followed by a brief description of internal specifications.
The back of the box gives a much more detailed description of “Tri-Stream 160 Technology,” which is the company’s method of utilizing three simultaneous 867Mbps streams on the 5GHz band to deliver 2.6Gbps peak speeds. Also displayed is a brief description of MU-MIMO technology and an illustration of how it offers simultaneous connectivity to multiple devices versus SU-MIMO’s one device at a time approach.
Upon opening the box, Linksys has carefully inserted the router’s four external antennas into four Styrofoam cutouts and padded the lining with extra foam to prevent shipping mishandling. The router itself is neatly tucked in the center, followed by documentation and accessories at the bottom.
The total contents of the box include the WRT3200ACM router itself, four external antennas, a Quick Start Guide, a power cable, a driver disc with documentation, and a 5-foot flat style Ethernet cable.
The Linksys WRT3200ACM features an enterprise-grade 1.8GHz Marvell Armada 385 88F6820 CPU with 256MB of NAND flash and 512MB of RAM. The WLAN interface uses a Marvell Avastar 88W8964 4 x 4 MIMO dual-band chipset powered by a dual-core Cortex A9 CPU. The WLAN chipset also supports Beamforming to enhance signal reception on the client side.
The WRT3200ACM is also certified for Dynamic Frequency Selection (DFS), which allows unlicensed devices to operate on a subset of 5GHz spectrum that is traditionally used for radar systems (industrial, TV weather stations, boats, federal civilian, military bases, etc.). In other words, if the router detects a nearby radar system on a particular 5GHz channel, it can automatically switch to an alternate channel without causing interference to any nearby radars. This feature was introduced back with 802.11a, the first 5GHz standard, but has become a crucial requirement with 802.11ac due to the use of wider 80MHz and 160MHz bandwidth channels.
As NetworkComputing explains, “Radar sends out a blast of radio waves that bounce off objects and return to the sensors. When RF signals from Wi-Fi hit the same sensors, the radar can’t distinguish them from the waves it sent out. Instead, the radar thinks the Wi-Fi’s radio waves are its own waves bouncing back and interprets them as solid objects.”
Official DFS documents define “very close proximity” as any Wi-Fi routers that are within 35km (21 miles) of Doppler Radar (TDWR) locations.
We tried detaching the hood to see the internal hardware layout but discovered three large aluminum heatsinks for the CPU, WLAN chipset and antenna circuitry.
On the back are four Gigabit LAN ports, a single WAN port for Internet connectivity, one USB 2.0 port, one USB 3.0 port, and an eSATA port. In terms of wireless connectivity, the upgrade from the WRT1900ACS to the WRT3200ACM includes next-generation 802.11ac Wave 2. As we mentioned previously, this brings support for MU-MIMO and 160MHz channel width on all three spatial streams over the 5GHz band.
Additionally, the router supports custom firmware installations from OpenWRT and DD-WRT.
At the time of our testing, there were no wireless 802.11ac client devices or adapters with support for 160MHz channels. Earlier last month, Intel silently introduced its 5th-generation Wireless-AC 9260 adapter, which will be the first to support MU-MIMO with 160MHz channels and delivering up to 1.73Gbps in downlink bandwidth. Unfortunately, they still aren’t available in retail, so for our testing purposes we went with two notebooks featuring Intel’s 4th and 2nd generation 802.11ac – one supports MU-MIMO, the other does not.
The first notebook we used for testing is an HP Spectre x360 (late 2016) equipped with an Intel dual-band Wireless-AC 8265 chipset, Intel ProSet Wireless software 184.108.40.206, jperf 2.0.2, and Windows 10 Pro.
The second notebook is a Lenovo ThinkPad T440s (mid-2014) equipped with an Intel dual-band Wireless-AC 7260 chipset, Intel ProSet Wireless software 220.127.116.11, jperf 2.0.2, and Windows 10 Pro.
On both notebooks, we disabled the MIMO Power Save Mode option (Spatial Multiplexing Power Save mode) on the network cards in order to make sure none of the radios would be put into a low-power mode. We also enabled the Throughput Booster option and made sure Transmit Power was on its highest (Level 5) setting.
The third device used for testing is an Apple iPhone 6 was equipped with iOS 10.3.2 and the iPerf – Bandwidth and Performance Test 1.12 app.
For our testing software, we used a popular network performance measurement utility called jperf (a GUI version of iPerf), which allowed us to measure wireless throughput over multiple simultaneous data streams running through the WRT3200ACM from client devices to a host device. To accomplish this, we ran a Windows 10 Pro desktop in “Server Mode” over Gigabit LAN and connected it with two 802.11ac Wave 2 capable notebooks, and an 802.11ac Wave 1 capable iPhone 6. Unfortunately, Apple is the most significant remaining vendor that has yet to launch an MU-MIMO enabled smartphone, and we expect this will happen with the iPhone 8 later this fall.
The server desktop we used for jperf testing is based on an Intel X99 chipset equipped with an Intel I210 Gigabit Ethernet Controller, Intel Network Connections Software 22.3, jperf 2.0.2, and Windows 10 Pro.
In regards to the Linksys WRT3200ACM’s firmware, we received the device with firmware 18.104.22.168944 installed. Upon installation, we checked the firmware update page and discovered 22.214.171.124030 dated April 5th, which includes a new WLAN driver and multiple bug fixes.
Testing environment – single story house (15 feet, 40 feet, 60 feet)
All bandwidth tests were performed in a single-story house with no other operational routers or cordless phones in the same indoor environment. The first test was conducted between a single wall, with the router placed 8 feet above ground and the three networked devices placed 15 feet away on the other side. The second test was conducted between two walls in a more traditional living room workplace area, where the router was approximately 40 feet away from all three devices.
Range performance – 802.11ac vs 802.11n
Before we began testing wireless performance, we immediately opened Network and Sharing Center to view the signal strength of each wireless network in various parts of the house.
Based on the results, 802.11ac gives 866.7Mbps at 15 feet from the router, 520Mbps in a living room environment and at the kitchen table (40 feet), and 9Mbps outside on the front porch.
On the other hand, 802.11n gives 144.4Mbps just a few feet from the router, 130Mbps in a living room environment and at the kitchen table (40 feet), and 43.3Mbps outside on the front porch. Here, the 2.4GHz band really starts to show its strength at longer distances from the router, yet is inherently limited by throughput speeds over the newer 802.11ac standard.
Test 1: 802.11ac 5GHz at 40 feet (kitchen table)
For our 802.11ac 5GHz test at 60 feet, we ran jperf utility on the HP Spectre x360 (2x2 MU-MIMO) using the WRT3200ACM’s increased 160MHz channel width. We wanted to see if there were any particular channels that resulted in smoother performance.
By sending four parallel data streams to our notebook, we discovered that channels 56, 100 and 116 produced some of the most consistent signal retention patterns during our 60 second test.
In contrast, some channels like 36 and 44 would keep the same curvature patterns across all four streams, but the data would not be sent at the same throughput rates.
Other channels like 64 and 108 would assign one data stream a majority of the data, while the other three followed along at much lower yet consistent data rates.
We tested the entire 802.11ac channel lineup available for 160MHz channel widths, which included 36 through 128 (5.18 to 5.64GHz). The lowest throughput during the 60 second test came from channels 36 and 100 (43.6Mbps and 44.5Mbps), while the highest came from channels 56, 60, 108 and 116 (61.1Mbps, 61.4Mbps, 63.3Mbps and 61.1Mbps, respectively).
Test 2: iPhone 6 802.11ac performance (15 feet and 40 feet)
Next, we tested the iPhone 6 using 802.11ac at the same 60-foot distance between two walls in the living room, which might emulate a typical household usage scenario at the dining room table. Using iPerf app, the phone was able to achieve an average of 70Mbps with a peak of about 75Mbps.
At a 15 foot distance between just a single wall, the iPhone 6 was able to achieve 94.1Mbps during a 673MB file transfer over a 1 minute interval.
Test 3: Two notebooks simultaneously (802.11ac 5GHz, 15 feet)
For our third test, we positioned both the HP Spectre x360 and Lenovo Thinkpad T440s at 15 feet from the router, just a single wall apart. We ran the jperf utility simultaneously on both to measure MU-MIMO throughput over 5GHz, while the 2.4GHz radio was switched off.
Based on the results, the ThinkPad T440s averaged 45.4Mbps while the Spectre x360 averaged 57Mbps, for a combined 102.4Mbps of total throughput.
Test 4: Three devices simultaneously (802.11ac 5GHz, 15 feet)
For our fourth test, we brought all three devices within 15 feet of the WRT3200ACM and ran jperf using eight simultaneous data streams for the two notebooks. The test ran for 60 seconds, allowing us to observe the full benefits of a tri-stream 160MHz channel width router broadcasting to three devices at once.
Based on the results, the ThinkPad T440s averaged 41.13Mbps, the Spectre x360 averaged 45.32Mbps, and the iPhone 6 got 28.4Mbps, for a combined total of 114.85Mbps.
We ran the test a second time just to confirm the results. In our second run, the ThinkPad scored 39.06Mbps, the Spectre scored 45.51Mbps, and the iPhone 6 scored 20.2Mbps, for a combined total of 104.77Mbps.
Test 1: Single notebook (802.11n 2.4GHz Auto mode, 15 feet)
In our first 802.11n test, we ran the ThinkPad individually on Auto mode (802.11n Only), where the router selected the best channel and an appropriate channel width. Based on the results, the notebook scored 28.48Mbps, a far cry from the lower triple digit performance in our 802.11ac results.
Test 2: Single notebook (802.11n 2.4GHz 20MHz Only, 15 feet)
In our second 802.11n test, we ran the ThinkPad individually in 20MHz channel mode, which yields a maximum theoretical single stream bandwidth of 72.2Mbps. Based on the results, the notebook scored 27.21Mbps.
802.11ac/n Combination Results
For our final test, we connected the the Spectre x360 and iPhone 6 to the 802.11ac 5GHz network and ran the ThinkPad T440s on the 802.11n 2.4GHz network. The goal was to measure the router’s acclaimed 3200Mbps theoretical peak performance, though we did not have enough wireless devices available to test three in MU-MIMO on 5GHz (867Mbps each) and four on 2.4GHz (600Mbps).
Based on the results, the Spectre x360 scores 50.58Mbps, the ThinkPad T440s scores 36.29Mbps, and the iPhone 6 scores 13.39Mbps, for a combined total of 100.26Mbps.
Conclusion – twice the performance of traditional 802.11ac with the right hardware
The biggest drawback to our testing of the Linksys WRT3200ACM router was the lack of any client 802.11ac adapters with support for 160MHz channels. As mentioned previously, Intel just announced its 5th generation 802.11ac adapters last month and they are expected to become available later this summer. When they do, we can expect to utilize the router’s full support for MU-MIMO at up to 1.73Gbps, which is double the speed at which we can connect for now (867Mbps).
The overall design of the WRT3200ACM is very reminiscent of the classic WRT54G from 2002 that dominated store shelves for over a decade, though the product is more of a direct successor to an earlier 802.11ac release, the Linksys WRT1900ACS. The company has not skimped out on processing power by any means, packing its latest WRT with a robust dual-core 1.8GHz Marvell Armada 385 (Cortex A9-based), and another Cortex A9-based Marvell Avastar 4 x 4 MIMO dual-band chipset with support for beamforming and Tri-Stream 160MHz.
In our testing on three 80MHz 802.11ac client devices, we were not able to even come near the theoretical 2600Mbps speeds on the 5GHz band. By running twenty simultaneous data streams across two notebooks and an iPhone 6, we were able to reach a maximum of 115Mbps in our MU-MIMO testing environment. With just two notebooks connected, we saw a combined 102.4Mbps of throughput, and with a single device we reached 63.3Mbps on channel 56. Meanwhile, our iPhone saw an average throughput rate of 70Mbps with 12ms of latency.
Depending on the surrounding environment, 5GHz channel choice can be a very important decision. We tested all available channels and discovered that 56 and 116 were produced the most consistent throughput curves on our charts, though mileage may vary.
Performance was also very consistent in mixed 802.11ac/n mode with both radios enabled. Our graphs show a combined throughput between all three devices at 100Mbps, which is on par with our 802.11ac-only results.
On the other hand, 2.4GHz performance over 802.11n was above par compared to most other routers on the market. We were able to get 28.48Mbps in our jperf test, followed by 27Mbps in 20MHz only mode.
The Linksys WRT3200ACM offers a lot in terms of customization with support for open-sourced DD-WRT and OpenWRT firmware packages. We did not have a chance a custom package on our review sample but suspect that a few very useful performance metrics can be adjusted even further, such as latency, buffer improvements, and transmit power. For a price of just $199, this router offers the top performance on the market with support for 160MHz channel width, despite the fact that no client devices will be capable of supporting it until later this summer. As of now, the WRT1900ACS is only $20 cheaper at $179.97, making this Tri-Stream router an investment in the future for users who don’t necessarily have the cash to upgrade all of their client devices.
802.11ac 160MHz is promising – should you be concerned about 802.11ax?
On the horizon is 802.11ax technology, which was introduced in a pair of chipsets from Qualcomm and Quantenna earlier in February. The technology is predicted to have a top speed of around 10Gbps, but the standard is not expected to be ratified until sometime in 2019. For now, most users upgrading to 802.11ac Wave 2 will be able to enjoy top speeds of 1.67Gbps with the introduction of 160MHz channel widths. In fact, Qualcomm is only promising 1.775Gbps with its first-gen 802.11ax hardware. So while the predicted sixfold improvement in speed is promising, the technology is still at least four years away for most consumers.