D-Link DSL-2750U, ADSL2+ wireless router with USB

Introduction

External design

Hardware

Firmware upgrade

Web-interface

Command line

Testing

Conclusion

Introduction

Once we already reviewed a kind of ADSL2+ modem ASUS DSL-G31 which allows connecting both to networks of ADSL operators and common Ethernet providers. Now our laboratory hosts another router; this time it is ADSL2+ D-Link DSL-2750U. Let's see what this model is capable of.

External design

The ADSL2+ modem under review comes in a black plastic case with dimensions of 160x128x36 mm not including the non-detachable antennae. To work properly D-Link DSL-2750U needs an external power unit with the following characteristics: 12В/1А.

On the front panel there are LEDs indicating status of the device (Power) and its ports (LAN 1-4, WLAN, USB, and DSL), as well as the status of WPS and provider authentication process (Internet).

Side panels are not remarkable at all and there are only ventilation grates on them.

The upper panel also has some ventilation holes and a 3D brand tag on it.

On the bottom of DSL-2750U there are stickers with brief information about the device, four rubber legs, and two tooling holes used to mount the device on the wall. There is also a ventilation grate here, which tells us that this device probably needs enhanced cooling. Sunken Reset button is used to reset the user settings back to the factory defaults.

The rear panel has four LAN ports and one DSL interface on it. Also, there is a USB2.0 port located here (which is painted the way as if it was its 3.0 counterpart), as well as external power supply socket, on/off button, WPS button, and wireless module Power button. Two non-detachable wireless antennae are located along the sides on the rear panel.

Now let's have a look at the insides of the case.

Hardware

The electronic stuffing of DSL-2750U is one green textolite card which has all essential elements located on one of its sides.

The logic component of the device is powered by a Broadcom BCM63281TKFBG chip. A BCM63281TKFBG module of the same-named brand is charged with duties regarding wireless network. A Samsung K4T56163QI chip acts as RAM.

Now let's pass on to reviewing of the software capabilities of the device.

Firmware upgrade

Firmware upgrade is carried out in Update Software section, Management group of the web-interface. Using Summary section, Device Info group, one can obtain information on the current firmware version.

The whole procedure takes about a minute. We have updated the version from 1.00 to 1.0.11. The vendor has updated the web-interface in the new firmware version. Now the upgrade process is performed in “Firmware upgrade” tab, “System” group, while information on the current firmware version can be found in “Start” group.

Apart from the conventional firmware upgrade method specified above, it is also possible to upgrade the firmware in the recovery mode. D-Link DSL-2750U switches to the emergency mode upon an unsuccessful firmware upgrade. It can also be switched to the emergency mode manually by pressing Reset button for ten seconds when the device is loading. The recovery process is easy enough; one just needs to choose a file with the new system image and click on Update Software button.

That is where we bring review of the firmware upgrade process to a conclusion and pass on to examining capabilities of the device web-interface.

Web-interface

One can access the web-interface of the ADSL D-Link DSL-2750U router with any modern browser just by entering the IP address assigned to the LAN-interface. By default, it is 192.168.1.1. In order to enter it, an administrator must specify login and password, which are admin/admin by default. Web-interface is available in seven languages.

Upon the successful authentication the administrator will find himself/herself on the home page of the device where he/she can manage the essential router operation parameters, backup/restore/reset the user settings, and reboot the device under review.

“Configure manually” icon gets an administrator to the pages with advanced settings. Let's have a closer look at them. In “Start” tab the information on the firmware version, serial ID, LAN-interface address, and status of the ADSL connection are displayed.

In tabs of “Status” group one can find out status of the local and DSL connections, routing table, DHCP server operation parameters, and other information.

WAN tab in “Net” group allows an administrator to choose a provider or specify all connection parameters manually.

Operation parameters of the device LAN-interface and DHCP server are located in “LAN” tab, the same group.

Upon a loss of connection, DSL-2750U can route the user traffic to a stand-by channel. These settings can be applied in “Watchdog” tab.

Wireless module operation parameters are located in tabs of “Wi-Fi” group. Ability to establish a guest network and choose the channel bandwidth are pretty nice options to our opinion.

SNMP, UPnP, and DDNS protocol operation parameters are located in the same-named tabs in “Advanced” group.

In order to connect to Triple-play services one would probably need to have interface linking to connect internal interfaces with external connections. These settings can be applied in “Interface grouping” tab.

One can manage the DNS operation parameters in “DNS” tab.

Wireless ADSL router D-Link DSL-2750U supports both static and dynamic routing (RIP), settings of which are made in “Routing” and “RIP” tabs.

Using “ADSL” tab one can choose the telephone pair and add-ons supported.

External access management is carried out by using “Remote access” tab. Alteration of the access parameters is available for the following protocols: HTTP, ICMP and Telnet. We believe that a more pliant system of settings, which also supports the SNMP, would be a reasonable addition here.

Management of transmitted data filtration parameters and access settings to virtual servers located on LAN is carried out using tabs of “Firewall” group.

One can connect various 3G modems, printers, or external HDDs to the device USB port. Settings of the connected units are located in “USB modem” and “USB storage” tabs.

Management of access to certain web-sites on WAN is carried out using tabs in “Control” group.

By using tabs in “System” group, an administrator can manage the device settings, upgrade the firmware, browse through the system log, change password, synchronize or set the time, and check the availability of remote nodes.

That's where we bring the review of web-interface capabilities to a conclusion. Now let's have a look at the device command line.

Command line

By default, telnet access to the device is accepted. The login and password are the same that were used while configuring the web-interface. Upon successful authentication the administrator receives brief information on the device model, firmware version, and board ID. One can receive the same info using fwversion command from /VERSION file, the process of obtaining access to which is described below.

Login: admin
Password:
NAME=DSL-2750U
VERSION=1.0.11
BUILDTIME=Tue Apr 17 16:24:03 MSK 2012
VENDOR=D-Link Russia
BUGS=<
This email address is being protected from spambots. You need JavaScript enabled to view it.>
SUMMARY=Root filesystem image for DSL-2750U
BOARDID=963281TAVNG
For help, type 'help' or '?'.
DSL-2750U# ?
Usage:
Common commands:
reboot
save
reset
restore http://192.168.62.2/configs/config.xml
backup http://192.168.62.2/configs/config.xml
upgrade http://www.dlink.ru/firmvares/firmware.img
fwversion
sh
ps
ifconfig
exit
help|?
For special commands, see special help:
show
create
set
remove
or:
wan
lan
vservers
raccess
ipfilter
urlfilter
routing
dhcp
ddns
dmz
upnp
wifi

Using CLI an administrator can upgrade the firmware, backup and restore the user settings, and perform a few other functions. By inputting ps and ifconfig commands, one can learn the processes being launched at the moment and network interface configuration parameters.

DSL-2750U# ps
PID Uid VmSize Stat Command
1 admin 408 S init
2 admin SW< [kthreadd]
3 admin SW [sirq-high/0]
4 admin SW [sirq-timer/0]
5 admin SW [sirq-net-tx/0]
6 admin SW [sirq-net-rx/0]
7 admin SW [sirq-block/0]
8 admin SW [sirq-tasklet/0]
9 admin SW [sirq-sched/0]
10 admin SW [sirq-hrtimer/0]
11 admin SW [sirq-rcu/0]
12 admin SW< [events/0]
13 admin SW< [khelper]
16 admin SW< [async/mgr]
60 admin SW< [kblockd/0]
69 admin SW< [khubd]
98 admin SW [pdflush]
99 admin SW [pdflush]
100 admin SWN [kswapd0]
102 admin SW< [crypto/0]
130 admin SW< [mtdblockd]
229 admin 464 S -sh
258 admin SW [dsl0]
273 admin SW [bcmsw]
301 admin 800 S smd
302 admin 1480 S ssk
309 admin 388 S dnsproxy
480 admin 932 S dhcpd
604 admin 1396 S wlmngr -m 0
643 admin 116 S /bin/wlevt
771 admin Z [smbd]
784 admin Z [resident]
785 admin Z httpd
786 admin 308 S resident_cli
787 admin 292 S dsldiagd
788 admin Z [smd]
790 admin 280 S httpd
791 admin 968 S resident -m 0 start
866 admin 636 S resident -m 0 start
867 admin 764 S resident -m 0 start
870 admin 1736 S smbd -D
871 admin 804 S smbd -D
28872 admin 900 S telnetd
28873 admin 608 S telnetd
28879 admin 404 S sh -c ps
28880 admin 408 R ps
DSL-2750U#
DSL-2750U# ifconfig
bcmsw Link encap:Ethernet HWaddr 1C:BD:B9:7C:24:19
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:23771 errors:0 dropped:0 overruns:0 frame:0
TX packets:14149 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:3338045 (3.1 MiB) TX bytes:7251092 (6.9 MiB)
Base address:0xda00
br0 Link encap:Ethernet HWaddr 1C:BD:B9:7C:24:19
inet addr:192.168.1.1 Bcast:192.168.1.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:22550 errors:0 dropped:0 overruns:0 frame:0
TX packets:14275 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:2769036 (2.6 MiB) TX bytes:7161193 (6.8 MiB)
br1 Link encap:Ethernet HWaddr 1C:BD:B9:7C:24:19
inet addr:192.168.2.1 Bcast:192.168.2.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:1 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:60 (60.0 B)
br2 Link encap:Ethernet HWaddr 1C:BD:B9:7C:24:19
inet addr:192.168.3.1 Bcast:192.168.3.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:1 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:60 (60.0 B)
eth0 Link encap:Ethernet HWaddr 1C:BD:B9:7C:24:19
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:23771 errors:0 dropped:0 overruns:0 frame:0
TX packets:14149 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:3338045 (3.1 MiB) TX bytes:7251092 (6.9 MiB)
eth1 Link encap:Ethernet HWaddr 1C:BD:B9:7C:24:19
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:4965 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:501336 (489.5 KiB)
eth2 Link encap:Ethernet HWaddr 1C:BD:B9:7C:24:1B
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:7 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:634 (634.0 B)
eth3 Link encap:Ethernet HWaddr 1C:BD:B9:7C:24:19
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:4965 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:501336 (489.5 KiB)
eth4 Link encap:Ethernet HWaddr 1C:BD:B9:7C:24:19
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:4965 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:501336 (489.5 KiB)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:6 errors:0 dropped:0 overruns:0 frame:0
TX packets:6 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:294 (294.0 B) TX bytes:294 (294.0 B)

In order to get acquainted with the current statuses and settings, one must use show command group. Commands create, set, and remove are used in order to create, change, set, or remove certain parameters.

DSL-2750U# show
show wans
show lans
show dhcps
show vservers
show raccesses
show dmz
show ddns
show routing
show upnp
show ipfilters
show urlfilter config
show urlfilters
show usbmodem
show wifi
show wifi clients

WAN and LAN interface management is to be carried out using commands of wan and lan groups.

DSL-2750U# wan
show wans
create pppoe|pppoa [vpi vci] [username password [service] ]
create mer|ipoa|bridge [vpi vci] [igmp]
set iface(atm0|ipoa0|ppp1 - see "show wans" second field) mtu 1492
set iface(atm0|ipoa0|ppp1 - see "show wans" second field) vpi 8
set iface(atm0|ipoa0|ppp1 - see "show wans" second field) vci 38
set iface(atm0|ipoa0|ppp1 - see "show wans" second field) pvc 8 38
set iface(atm0|ipoa0|ppp1 - see "show wans" second field) encapsulation llc/snap|vc/mux
set iface(ppp1|ppp2 - see "show wans" second field, type must be pppoe or pppoa) username user
set iface(ppp1|ppp2 - see "show wans" second field, type must be pppoe or pppoa) password pass
set iface(ppp1|ppp2 - see "show wans" second field, type must be pppoe or pppoa) service pppserver
set iface(ppp1|ppp2 - see "show wans" second field, type must be pppoe or pppoa) auth user [ pass [pppserver]]
set iface(atm0|ipoa0 - see "show wans" second field, type must be mer or ipoa) ip 55.55.55.55 [255.255.255.0 [55.55.55.1]]
set iface(atm0|ipoa0 - see "show wans" second field, type must be mer or ipoa) gw 55.55.55.1
set iface(atm0|ipoa0 - see "show wans" second field, type must be mer or ipoa) igmp on
set iface(atm0|ipoa0 - see "show wans" second field, type must be mer or ipoa) igmp off
set iface(atm0|ipoa0 - see "show wans" second field, type must be mer or ipoa) nat on
set iface(atm0|ipoa0 - see "show wans" second field, type must be mer or ipoa) nat off
remove wan iface(atm0|ipoa0|ppp1 - see "show wans" second field)
DSL-2750U# lan
show lans
set lan ip 192.168.0.55 [255.255.255.0]

Remote access to the device and local network services is gained using vservers, raccess, dmz, and upnp commands.

DSL-2750U# vservers
show vservers
create vserver tcp|udp|tcp/udp b_ext_port [e_ext_port] b_int_port [e_int_port] int_ip [ext_ip] iface(atm0|ipoa0|ppp1 - see "show wans" second field) name
remove vserver name
DSL-2750U# raccess
show raccesses
create raccess http|telnet|icmp all|br0|iface(atm0|ipoa0|ppp1 - see "show wans" second field) all|ip|ip/mask(192.168.1.0/255.255.255.0) name
remove raccess name
DSL-2750U# dmz
show dmz
set dmz on 192.168.0.55
set dmz off
DSL-2750U# upnp
show upnp
set upnp on
set upnp off

Management of DHCP and DDNS protocols is performed using the same-named commands.

DSL-2750U# dhcp
show dhcps
set dhcp on
set dhcp off
set dhcp range 192.168.0.60 [192.168.0.90]
set dhcp time 99999
DSL-2750U# ddns
show ddns
create ddns dlinkddns|dyndns|tzo my.dyndns.org(host_name) user pass iface(atm0|ipoa0|ppp1 - see "show wans" second field)
remove ddns my.dyndns.org(host_name)

Setting wireless network parameters is done using wifi command.

DSL-2750U# wifi
show wifi
show wifi clients
create wifimacfilter mac
set wifi on
set wifi off
set wifi hide on
set wifi hide off
set wifi ssid SSID
set wifi country RU
set wifi channel 6
set wifi auth open|wpa-psk|wpa2-psk
set wifi encryption wep(open)|none(open)|aes(wpa-psk|wpa2-psk)|tkip+aes(wpa-psk|wpa2-psk)
set wifi pskkey KEY(8-63 characters)
set wifi wepkey KEY(5 or 8 characters)
set wifi macflmode disabled|allow|deny
remove wifimacfilter mac

The commands specified above are related to the device command line and are different from the OS commands. Access to the latter is gained by inputting sh command. It is conventional to see BusyBox library used in this kind of devices, and by inputting sysinfo of the library one can get brief information on the system operation. Also, the similar information can be learnt in /proc/loadavg and /proc/uptime files.

DSL-2750U# sh
BusyBox v1.00 (2012.04.17-12:16+0000) Built-in shell (msh)
Enter 'help' for a list of built-in commands.
# busybox
BusyBox v1.00 (2012.04.17-12:16+0000) multi-call binary
Usage: busybox [function] [arguments]...
or: [function] [arguments]...
BusyBox is a multi-call binary that combines many common Unix
utilities into a single executable. Most people will create a
link to busybox for each function they wish to use, and BusyBox
will act like whatever it was invoked as.
Currently defined functions:
[, busybox, cat, chmod, cp, dmesg, echo, expr, false, flash_eraseall,
gzip, httpd, ifconfig, init, insmod, kill, killall, klogd, linuxrc,
ln, logger, logread, ls, mkdir, mknod, modprobe, mount, msh, nc,
ping, ps, reboot, rm, rmmod, route, sendarp, sh, sleep, sysinfo,
syslogd, tail, tar, test, top, true, tty, umount, vconfig
# cat /proc/version
Linux version 2.6.30 (builder@rd) (gcc version 4.4.2 (Buildroot 2010.02-git) ) #1 Tue Apr 17 16:16:23 MSK 2012
# sysinfo
Number of processes: 48
9:03pm up 21:03,
load average: 1 min:0.00, 5 min:0.00, 15 min:0.00
total used free shared buffers
Mem: 27928 26960 968 0 2440
Swap: 0 0 0
Total: 27928 26960 968
# cat /proc/loadavg
0.00 0.00 0.00 1/48 28915
# cat /proc/uptime
75852.49 0.00

By using top utility one can obtain information on the current activity of the launched processes.

Mem: 26556K used, 1372K free, 0K shrd, 2376K buff, 8636K cached
Load average: 0.00, 0.00, 0.00 (State: S=sleeping R=running, W=waiting)
PID USER STATUS RSS PPID %CPU %MEM COMMAND
28926 admin R 428 28909 1.9 1.5 exe
870 admin S 1736 1 0.0 6.2 smbd
302 admin S 1480 301 0.0 5.2 ssk
604 admin S 1396 301 0.0 4.9 wlmngr
791 admin S 968 1 0.0 3.4 resident
480 admin S 932 301 0.0 3.3 dhcpd
28905 admin S 896 301 0.0 3.2 telnetd
871 admin S 804 870 0.0 2.8 smbd
301 admin S 800 229 0.0 2.8 smd
867 admin S 764 791 0.0 2.7 resident
866 admin S 636 791 0.0 2.2 resident
28906 admin S 604 28905 0.0 2.1 telnetd
28909 admin S 528 28908 0.0 1.8 exe
229 admin S 464 1 0.0 1.6 sh
1 admin S 408 0 0.0 1.4 init
28908 admin S 404 28906 0.0 1.4 sh
309 admin S 388 301 0.0 1.3 dnsproxy
786 admin S 308 301 0.0 1.1 resident_cli
787 admin S 292 301 0.0 1.0 dsldiagd
790 admin S 280 1 0.0 1.0 httpd

Let's find out what kind of content /, /proc, /bin, /sbin, /usr/bin and /usr/sbin catalogues have.

# ls /
VERSION dev linuxrc proc sys var
bin etc mnt sbin tmp webs
data lib opt share usr
# ls /proc
1 302 866 fs nvram
10 309 867 interrupts pagetypeinfo
100 4 870 iomem partitions
102 480 871 ioports scsi
11 5 9 irq self
12 6 98 kallsyms slabinfo
13 60 99 kcore stat
130 604 bcmlog kmsg switch
16 643 brcm kpagecount sys
2 69 buddyinfo kpageflags sysvipc
229 7 bus led timer_list
258 771 cmdline loadavg tty
273 784 cpuinfo locks uptime
28905 785 crypto meminfo version
28906 786 devices mii vmallocinfo
28908 787 diskstats misc vmstat
28909 788 driver modules zoneinfo
28927 790 execdomains mounts
3 791 fcache mtd
301 8 filesystems net
# ls /bin
3gcli ebtables msh smd
adsl echo nas snmpd
adslctl epi_ttcp nas4not sntp
bcmupnp ethctl ntfs-3g ssk
bftpd event nvram sysinfo
brctl false nvramUpdate tar
busybox fc ping tc
cat fcctl pppd telnetd
chat flash_eraseall ps true
chmod gzip rawSocketTest udhcpd
cmotech-cdswitch hotplug resident umount
cp initdongle resident_cli upnp
dboardid ip ripd urlfilterd
dconf ippd rm usb_modeswitch
ddnsd iptables rt_test_ping vlanctl
dhcpc kill rtvalved wl
dhcpd lld2d rtvdctl wlctl
dmac ln sedre wlevt
dmesg ls sendarp wlmngr
dnsproxy mcpd setmem wps_monitor
dnsspoof mkdir sh xdslctl
dsldiagd mknod sleep xtm
dumpmem mount smbd xtmctl
eapd mroute smbpasswd zebra
# ls /sbin
chat ifconfig klogd pppd.gpl route
ethctl init logread reboot syslogd
hotplug insmod modprobe rmmod vconfig
# ls /usr/bin
[ killall nc test tty
expr logger tail top
# ls /usr/sbin
drop_caches loadconfig resetconfig saveconfig
httpd reset_and_reboot save_and_reboot
#

And obtain information on the CPU and RAM size.

# cat /proc/meminfo
MemTotal: 27928 kB
MemFree: 1356 kB
Buffers: 2376 kB
Cached: 8636 kB
SwapCached: 0 kB
Active: 4768 kB
Inactive: 9732 kB
Active(anon): 1576 kB
Inactive(anon): 1912 kB
Active(file): 3192 kB
Inactive(file): 7820 kB
SwapTotal: 0 kB
SwapFree: 0 kB
Dirty: 0 kB
Writeback: 0 kB
AnonPages: 3508 kB
Mapped: 3100 kB
Slab: 7992 kB
SReclaimable: 504 kB
SUnreclaim: 7488 kB
PageTables: 324 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 13964 kB
Committed_AS: 8196 kB
VmallocTotal: 1032148 kB
VmallocUsed: 3640 kB
VmallocChunk: 1022116 kB
# cat /proc/cpuinfo
system type : 963281TAVNG
processor : 0
cpu model : Broadcom4350 V7.5
BogoMIPS : 319.48
wait instruction : yes
microsecond timers : yes
tlb_entries : 32
extra interrupt vector : no
hardware watchpoint : no
ASEs implemented :
shadow register sets : 1
core : 0
VCED exceptions : not available
VCEI exceptions : not available
unaligned exceptions : 1394
#

That's where we proceed to completion of the brief review of command line capabilities of the wireless ADSL D-Link DSL-2750U router and pass on to testing the device.

Testing

The first testing procedure we usually begin our testing section with is estimating the booting time of the device, which is a time interval starting with the moment when the power is on until the first echo reply is received through ICMP protocol. D-Link DSL-2750U boots in 24 seconds. We believe that the result is decent.

The second traditional test was a security scanning procedure, which has been carried out using Positive Technologies XSpider 7.7 (Demo build 3100) utility. On the whole, there were seven open ports discovered, and they are TCP-21 (FTP), TCP-23 (Telnet), TCP-80 (HTTP), TCP-139 (NetBIOS samba), TCP-445 (Microsoft DS), TCP-1780 (dpkeyserv) and TCP-8888 (ddi-tcp-1). The most interesting data are presented below.

Now we are coming close to the most interesting part in the review, a performance test. We decided to start with evaluating user data transmission speeds in the wireless segment of the network. Results of the measurements are presented on the diagram below.

Having decided not to limit ourselves only with checking the highest possible transmission speeds via ADSL, we also did measurements of several protocol standards separately.

One can connect an external HDD or flash card to the USB-port of the device. We connected an HDD which was successfully identified by the system and had its content displayed in the web-interface. However, access speeds to the user data stored on the external device were sadly surprising, to say the least of it.

We were also quite surprised by the method of data transmission to the device when using FAT32 file system (there was nothing of the kind when we used NTFS). At first, upon copying a file to the flash card via network, we couldn't manage to transmit the data to the card at all, though the transmitted file appeared on the disk (and its size kept growing on and on). When the file was eventually created, the device started transmitting the data with a speed much higher than those ones specified above. That is why the figures shown above are actually average speeds we received by dividing the file size by the total downloading time (preparation time and downloading time).

That's where we draw the testing chapter to a conclusion and move on to summing it all up.

Conclusion

The wireless ADSL router D-Link DSL-2750U we have tested is a reliable medium-grade device which is affordable for an average user. Its capabilities and performance will be enough for majority of users. Below are the strong points of the device.

  • Competitive price
  • Ability to create a wireless guest network
  • USB-port
  • Ability to establish a back-up connection

Unfortunately, we cannot help to mention certain drawbacks of DSL-2750U.

  • Low access speed to the data which are stored on an external HDD

As of when this article was being written, the average price for a D-Link DSL-2750U in Moscow online shops was 1500 roubles.

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