Speed drops down with router.

[robalrr]

Hi, I have very strange problem, I have the following devices:

Modem ADSL Pirelli DRG A115
Router D-Link DIR-615
Notebook Ubuntu 11.10
Notebook Windows 7
Smartphone Android 2.3.5

My connection is ADSL with 2Mbps broadband. Using speedtest.net for testing the speed I got almost 2Mbps, that is ok, but this is connected directly to the modem. The problem is when I use the router, when I connect it the speed downs onward until it achieve a stable value of 512kbps, that is 4 times less than my contracted speed. I have tried with four different D-Link routers (DIR-280, DIR-600, DIR-600 N150, DIR-615), four ones give the same problem.

D-Link tech support people don't have idea about what is happening just like tech support people from my Internet provider. I think the problem is not the modem because I get 2Mbps from it connected directly (without the router).

I do the speed test in an interval of 3 minutes between each test, with just one device connected and only doing the speed test, all programs that use Internet access are closed.

Always is the same, after a time the speed drops down, from 2Mbps until 512kbps. The router has the QoS disabled, I have tried changing the MTU value, I have tried some values 1492 (this is the official from the Internet provider), also I have tried some lower numbers 1400, 1200 but the result is the same.

The router has as security only wpa2 and it has a static public IP, the modem is configured as bridge. I have also tried unplugging the phones, connected to the splitter, keeping away the wireless phones, moving away the router from the modem for electronic interference, modifying the WAN speed from auto to 10 and 100, I have disabled the firewall, change the channels and power TX. I do the speed tests using the wireless and wired interfaces.

I don't have idea what is happening I have read several forums and helps but always I get the same result. I really appreciate any suggestion.

[2xg]

Welcome to TSF,

2mbps is really not that much. Have you tested all wireless devices and ran speedtest as well?

[robalrr]

Hi, 2Mbps is the speed I have contracted, I know it is not to much for normal connections but I can't contract more than that.

I have tested all the wireless devices and also the router wired ports, I always get the same result.

Since my original post I have tried disabling the DHCP server and I forgot to say I updated the router's firmware.

I am thinking about a problem with the pair modem-router, because when the router is recently turned on I got the full speed from it, the speed is reduced some minutes later. But in this moment I don't have any idea of what is happening neither an action plan.

[2xg]

When you ran speedtest on all wireless devices, were the rest of them not heavily utilizing the bandwidth such as uploading and downloading files or heavy gaming?

You may try to reset the router back to factory settings. Prior to this, make sure to do Print Screens of the router's configurations then reconfigure from scratch and start fresh. See if that helps.