The RT-N56U has two USB 2.0 ports which can be used to connect external storage devices and printers. There is also a special version of firmware that supports 3G modems. We couldn’t find any of the modems we had at hand in the compatibility list, so we didn’t test this feature. USB hubs are not supported.
A utility for setting printer access up is included into the software bundle. It supports not only printing but also scanning with some all-in-ones, but we couldn’t check this out, either.
The RT-N56U supports external disks formatted in FAT32, NTFS, EXT2 or EXT3. You can access them via the network environment or FTP. Every service and file system supports Unicode, so there should be no problems with character encoding.
You can create user accounts with logins and passwords for access control (there is no superuser or administrator in this service). After that you can assign access rights for each folder on the disk volume, separately for FTP and CIFS protocols. The assignment of rights to individual folders rather than to the whole disk volume may seem to be inconvenient but allows creating resources with different access rights for different users on a single disk. The user rights information is stored on the disk itself, in a few hidden files in the root directory. The speed of working with external disks is not very high, 11 to 28 MBps, depending on the protocol and file system. The following diagram shows the speed of reading/writing large (1GB) files from/to a 250GB external drive from WD.
The additional service settings include server/workgroup name and a limit on the number of simultaneous connections.
Included with the router is a set of utilities that help set it up, connect a printer, find the router on the LAN, restore its firmware, connect WPS clients, and manage file downloads. You can connect a USB drive and download files (up to five files simultaneously) to it via HTTP/FTP or Torrent. The data-transfer speed is up to 2 MBps and higher in this mode. Everything works fine, but active users will hardly be interested in this feature because it lacks any settings. Files are only seeded when being downloaded, and you cannot control their placement. This feature just creates a Share folder with a few subfolders on the first available disk volume.
There are two more scenarios of using external disks. They can store an iTunes library or work as a DLNA server. Multimedia files can be located in any folder on a connected disk, and there are no settings to change this. The supported file formats include most HD video formats, particularly mkv and m2ts. If the router isn't doing much other work, you can even watch Full-HD remuxes from it. Other DLNA devices are supported as well, but the number of formats can be limited by your TV-set or music box.
The data-transfer speed between the router’s WAN and LAN ports was measured with the iperf package. Every client was running Windows 7 64-bit while the ISP’s server was emulated by a Linux machine with remote access and routing services. The speed was measured for a client connected to one of the router’s LAN ports.
The results indicate that the router is indeed very fast. The data transfer speed is up to 1 Gbps with direct connection. It’s only half that much with PPPoE, but 500 Mbps is an excellent performance, too. Well, there are not so many users who can afford a Gigabit connection to the Internet and those who can, will certainly be able to afford professional network equipment.
The RT-N56U can effectively use a 100Mbps channel when using PPTP or L2TP connections.
We wouldn’t pay much attention to the considerable misbalance in the results of the tests when data is being sent and received simultaneously because such scenarios are rather unlikely. It's important that the overall performance of the router is going to be quite high even with such a scenario.