by Platon Scheblykin
06/18/2009 | 04:28 PM
In this review we will be discussing the long-anticipated wireless router from ASUS called RT-N15. ASUS was one of the first manufacturers to introduce a home router with support for 802.11n draft. It was the WL-500W model but, like nearly every other home router of that time, it was equipped with Fast Ethernet ports. The Fast Ethernet interface was the router’s bottleneck which prevented it from showing its full potential. So, we have been waiting for ASUS to release a similar Gigabit Ethernet router like other brands have done already. Finally, we’ve got it, even though its specifications are not as impressive as we might wish (something high-end like the WL-500g Premium would be demanded, we guess). The RT-N15 does not stand out among its opponents. It offers just the basic functionality of today’s devices of its class. However, there are a few special features about it, too. So, let’s get started.
- IEEE 802.11b/g
- WEP (64/128bit)
3 x 3dBi RP-SMA antennas
OFDM, CCK, DQPSK, DBPSK.
2.412 ~ 2.462GHz (FCC)
- 11n: 16±1dBm
- 11n (40MHz): -68dBm
Nominal data transfer rate
- 802.11n (draft): up to 300Mbps
11 for North America, 14 Japan,
1 RJ-45 GigabitEthernet 10/100/1000Mb/s
4 RJ-45 GigabitEthernet 10/100/1000Mb/s
External power supply unit
192(L) x 115(W) x 29(H) mm
- WiFi certified
The box contains:
The exterior design has changed dramatically since the WL-500W, the first Draft N router from ASUS. The RT-N15 is far more compact in the first place. It is now like a small book with one slanted corner. The resemblance is emphasized by the materials: the back and side panels are cream-colored plastic whereas the top and front are made from translucent plastic painted silvery from the inside, which looks like pages of a book. The photo does not show it, but the light surfaces of the case have a stylish nacreous shimmer. This coating may seem scratchable and easily soiled, but it actually retained all its beauty throughout our intensive tests. ASUS’ designers have abandoned external antennas in the new router, so nothing sticks out of its case.
Instead, there are three planar antennas on the PCB, but you can attach external antennas to the available connectors.
The RT-N15 can be positioned upright only, the stand being attached to the router’s case. The stand can be turned and fixed at 90 degrees to the case.
The vent holes in the case also indicate that the router must be installed vertically. The holes at the bottom of the case are for cool air to come in. Cooling the PCB, this air then leaves the case through the holes at the top. This ventilation is enough since the router’s chips are not very hot. The case of the working RT-N15 is just barely warm.
The indicators, connectors and controls are placed like on most other home devices. That is, the indicators can be seen on the front panel (from left to right):
The designers have decided to separate the indicators and labels although we guess it would be better if the indicators were shaped like the corresponding icons or letters. They are large and perfectly visible, but the labels may be hard to see under dim ambient lighting. Blue LEDs are used in the indicators. Although such LEDs are usually very intensive, they do not irritate the eye here. The router’s back panel offers the following connectors and buttons (from left to right):
It was not easy to take the case apart. There are three screws in the bottom panel and a number of latches around the case. We don’t recommend you to dismantle your router as you can scratch or break its case and make the warranty void.
The PCB fills the entire case and carries all of the router’s components including a wireless module and antenna connectors. And as we have noted above, the antennas are wired on the PCB, too. The quality of manufacture is high. Nearly every chip is covered with a metal screen, excep the memory chips.
From a hardware point of view, the RT-N15 is an entry-level product. It is based on a highly integrated SoC controller RT2880 from Ralink which, besides the traditional selection of devices typical of network SoC controllers, incorporates a MAC controller of the 802.11n (draft) standard.
According to the developer, the RT2880 is the first iNIC WLAN product (iNIC stands for Intelligent Network Interface Card) implemented as a single chip. The chip enables communication with the main processor’s interface (PCI or Ethernet) and the processing of 802.11n traffic. The controller performs all of the resource-consuming jobs in the router, and we can’t expect high performance from its MIPS4K core clocked at 266MHz.
The Gigabyte Ethernet controller even looks more like a processor than the RT2880. It is a rather new model of Realtek’s network controller which is called RTL8366SR.
By the way, all of the router’s five network ports (not four, as usual) are based on this controller because the RT2880 has no Ethernet ports at all.
The RT-N15 has 32 megabytes of SDRAM in two K4S281632K chips from Samsung.
Its firmware is stored in a 29LV320CBTC-90G flash memory chip from Macronix. Its capacity is 4 megabytes.
The router also uses an RL2820 RF-module that is often employed together with the RL2880.
Finally, there is a bonding pad on the PCB for a console connector that may be installed to connect to the router via a serial interface.
We did not expect any surprises from this router’s firmware. And indeed we first saw a standard interface of ASUS’s top-end routers. It was not bad but somewhat hackneyed. As usual, we then downloaded the latest version of the firmware (188.8.131.52) available at the manufacturer’s website replacing the router’s original version 184.108.40.206. Rebooting the device, we found the web-interface completely different – and better!
We want to say a few words about the interfaces of modern home routers in general. The industry of home network equipment, including routers, is not new, but the manufacturers have mostly been focusing on the exterior design and functionality of their devices. Home routers acquired handy web-interfaces long ago but have not developed any further in this respect. The pages with settings are only superficially revised with the release of each new model, acquiring new settings and changing the design of buttons and frames, but remain largely the same in terms of visualization and convenience. On the other hand, a handy, intuitive and visual web-interface is a necessary thing for inexperienced users to be able to set the device up without problems.
So, ASUS seems to be one of the first makers of home routers that make a step towards a truly user-friendly interface. Perhaps not as handy as Synology’s, the web-interface of the RT-N15 has a number of small improvements over standard interfaces, which make it much easier to use. We guess it will become clear as we will discuss its components.
Upon successful authentication you find yourself in the start page of the setup manager. The color palette is very comfortable for the eyes, we should confess. The details of the interface are clear and pretty. All of this makes using it a real pleasure.
The web-interface window is divided into three sections: a header, a navigation menu (on the left) and a settings area (on the right). The header serves a practical purpose here, displaying the current firmware version, SSID and uptime. It allows to change the language of the interface, reboot the router or finish the setup session. The funny face in the top right corner reports the current status of the Internet connection with floating balloons.
The left frame of the web interface displays a menu in which you can choose one of six groups the settings pages are categorized into (under the Advanced Setting header) and two more items that can be useful for initial setup. When you choose a category, the menu does not show the sub-categories it contains, but it is not a big problem because the settings are distributed among the categories in a logical way and the names of the categories are indicative of their contents.
Besides, if you click the Advanced Setting link, you will see a full list of pages with settings and will be able to jump right to any page with a single click of the mouse button.
The rest of the window shows a horizontal submenu (the top line) listing all pages of the selected category and, below, the currently selected page with settings. To the left of them there is a column of the router’s integrated help system. You can hide it by clicking the appropriate icon in the corner. The help system is not comprehensive, but provides a general notion of what the particular menu option does. There is one user-friendly solution regarding the help system: the names of almost all options are designed as hyperlinks. So you can click any option and read about it in the help system window.
Before we discuss the available settings, we want to tell you about the two individual menu items we’ve noted above. They are called Network Map and EzQoS Bandwidth Management.
The contents of the Network Map item can be viewed right after you successfully log into the web-interface.
This item is meant to facilitate the initial setting up of the router and has replaced the quick setup wizard you can see in nearly every home router. We guess the Network Map is head above every setup wizard we have seen in usefulness, mainly because it is more visual. Like the name suggests, it is a simplified map of your home network. You can click any element with your mouse to display the basic settings of that element on the right. When you choose the settings you need, you can save them or perform a more detailed setup by using the More Config menu.
The EzQoS Bandwidth Management menu item is a simple traffic prioritization system that helps minimize latencies when the external connection is loaded fully.
This system has been available on ASUS routers for long and there is not much practical worth in it but it may be useful for people who do not know much about QoS or don’t care to write a lot of QoS rules manually.
The main menu then lists the categories the rest of the router settings are divided into. We will discuss them starting from the Wireless group.
The first page in this group is called General.
Most users will find the available settings sufficient for setting up their WLAN. You can rename the access point, specify the number and width of the communication channel, select an encryption mode, etc. There are as many as 6 WPA encryption variants to choose from.
On the WPS page connection settings can be automatically transferred to the client via WPS technology. The RT-N15 allows doing that with a special button, but only in the Network Map.
On the Bridge page you can set the RT-N15 up for WDS mode (Wireless Distribution System) so that it would work with other WDS-mode access points to expand your WLAN coverage. However, for such a WLAN to be more or less secure, all of its constituents must be RT-N15.
To allow only specific clients to access the router, you should go to the Wireless MAC Filter page and enter the MAC addresses of such clients into the list.
The address, port and password of the RADIUS server that can be used by the RT-N15 for client authentication are specified on the RADIUS Setting page.
The Professional page contains the rest of WLAN settings most of which pertain to low-level parameters of wireless connection and should not be tinkered with in most cases. We guess the most demanded feature in this page is the schedule you can define for the router’s wireless access point.
The next group of settings is called LAN. It includes the setup options of the router’s internal network. Particularly, the LAN IP page is for specifying the IP address the router will have on the LAN.
The DHCP Server page is about the router’s integrated DHCP server. You can specify DNS and WINS servers and a LAN gateway with addresses other than the RT-N15’s address, which is a rare option for a home router. You can also reserve IP addresses here.
There is no routing table item in the main menu, so the routing rules are specified on the Route page. The available options are sufficient for a home router.
The settings of the WAN category refer to the WAN port parameters. First goes the Internet Connection page where you can choose the type of connection with the external network and set up its parameters. You can also direct streaming traffic to a dedicated LAN port (which can be very useful, for example, for IP television).
The router’s QoS rules are specified on the QoS page. Unfortunately, there are few options here and, judging by some settings, the rules only apply to uplink traffic.
Port triggering rules are specified on the Port Trigger page. There are but two ready-made rules here.
For some servers on the LAN to be accessible from the WAN, you should write appropriate rules on the Virtual Server page. As opposed to the previous page, there is a long list of predefined rules here.
On the DMZ page you can send all incoming traffic to a specific machine on the LAN.
Your DDNS account parameters are specified on the DDNS page. There are four DDNS providers to choose from, like on most other home routers.
Various traffic filters can be found in the Firewall group although the General page offers some settings related to accessing the router from the outside. You can allow pinging the router’s WAN port and accessing the setup manager via that port. You can enable protection against DoS attacks but you cannot set any parameters of that protection.
The URL Filter can block traffic from specific external addresses by keywords. Scheduled filtering is possible, too.
The MAC Filter can block traffic from LAN devices with specific MAC addresses. You can choose the devices on this page.
The LAN to WAN Filter can block data transfers between any two devices one of which resides on the LAN and another, on the WAN.
The Administration group is needed for managing the router. The first page is called Operation Mode. The operation modes differ mostly in the status of NAT and the router’s physical ports.
The System page is where you can enter a new administrator password and specify a server for syncing the router’s system time with. Unfortunately, you cannot enter the time data manually.
The name of the Firmware Upgrade page is self-explanatory.
The last page with settings is called Restore/Save/Upload Setting. You can back up and restore the router’s settings here.
The last item of the main menu is called System Log. It offers a few information pages including router’s log, wireless connection log, lists of assigned IP addresses, active routes and forwarded ports. You cannot set up the detailedness of the logging feature, but it is quite detailed by default.
Summing it up, the RT-N15’s firmware has a good interface with a few interesting features but also a few drawbacks. Some demanded settings are missing. Still, we do not see serious drawbacks and consider the router’s firmware as very good.
We could predict some results of the RT-N15 in tests because we had tested two routers based on the same chipset and both had showed similar performance of the WAN ports. Those routers’ results had been rather low, so we did not expect anything exceptional from the RT-N15.
We take one of the two previously tested RT2880-based routers for the sake of comparison. It is the Edimax BR-6574n. It was far from impressive in our wired connection tests but delivered a surprisingly high speed of wireless connection. Besides the two routers, we will use the following equipment:
First we will measure the router’s maximum bandwidth using two of its LAN ports.
The results are indicative of the characteristic features of the RTL8366SR. It offers a high top speed but has frequent slumps.
Next we measured the bandwidth of the router’s WAN-LAN segment. We tested a direct connection as well as a VPN tunnel. As you know, a VPN connection is almost always accompanied with a considerable reduction in the data-transfer rate. We tested the direct connection by specifying the WAN port address manually and exchanging data between the two endpoints in both directions. When testing a VPN connection, we chose the PPPoE protocol. We established a PPPoE server on the Linux machine (see the list of test equipment above) and an IXIA endpoint. Then we connected the tested rooter to that server and attached a notebook with IxChariot to the router’s LAN. Here are the results for both routers.
The router had the same results irrespective of whether its firewall and QoS services were on or off. So, the results below refer to when the mentioned services were turned on.
LAN-WAN (ASUS RT-N15):
LAN-WAN (Edimax BR-6574n):
WAN-LAN (ASUS RT-N15):
WAN-LAN (Edimax BR-6574n):
PPPoE (ASUS RT-N15):
PPPoE (Edimax BR-6574n):
You can see that both routers deliver good performance although the BR-6574n is nearly always ahead of the RT-N15. This is odd as the two models are almost identical on the hardware level. Anyway, the results indicate that the RT2880 processor’s resources are utilized fully and you cannot expect high performance from routers based on it.
The next test shows the router’s performance with peer-to-peer networks (when there are many simultaneous connections). To perform this test we created a pair in IxChariot using the Throughput scenario in which we changed the file_size parameter from 100,000 to 1,000,000. Then we began to increase the number of pairs by replicating them until there were errors during the test. And the ASUS router came up the winner as it could maintain 200 simultaneous connections as opposed to the BR-6574n’s 160. This must be due to the fact that the RT-N15 has more system memory.
The wireless connection in draft 802.11n mode was tested using WPA2 PSK encryption with the AES algorithm. These security settings are the default ones in the draft version of the new standard and are likely to remain such in the final version.
The BR-6574n is good in this test even in comparison with some expensive top-end routers, so it is no wonder that the ASUS RT-N15 is inferior to it.
Finally we tested the router’s coverage at different distances and with different obstacles. We measured the signal level in five points:
Point 1: Near the router
Point 2: At a distance of 4 meters without obstacles
Point 3: At a distance of 5 meters + two thin gypsum wallboards
Point 4: At a distance of 6 meters + one brick wall, about 30cm thick
Point 5: At a distance of 17 meters + one thin gypsum wallboard and two 30cm brick walls
Here are the results:
The RT-N15 is better in this test. Its internal antennas are better than the external ones of the BR-6574n.
Having tested the RT-N15, we can say that it is no different from other RT2880-based products in terms of performance. The cheap chipset does not allow it to be fast. Its WAN speed is comparable to that of previous-generation routers with 100Mbps Ethernet. The good news is that the wireless connection speed of the RT-N15 meets the Draft N 2.0 requirements. Besides, the router has a large WLAN coverage zone.
The new router from ASUS makes a very good impression but mostly thanks to designers rather than engineers. The RT-N15 is stylish and offers very convenient user-friendly interface. It is, however, somewhat disappointing when it comes to performance. RT2880-based solutions are widespread on the market, so the RT-N15 is just a typical midrange product. It is no successor to ASUS’s 500 series. Hopefully, the future models of home routers from ASUS will add high performance and support for USB ports to the good features the RT-N15 already has.