@fammo You got it right. Depending on the device FW, some devices may or may not have so called "WDS mode" setting. Here's a thread which can throw some light on what I am talking about.

@hrupek According to its specs TL-WR820N can achieve theoretically 100mbit/s bandwidth on its WAN/LAN ports.

@fammo I can't say what's the reason for the "Error code: 4503", but the reason you don't have access to the extended router (VR300) is most probably that VR300 can't build WDS with your root router....

@Geboers You can connect whatever device you want to one of these ports - switch, router, desktop computer. It depends on what you're trying to achieve.

@fammo Make sure that you're with the latest FW for your VR300 - here. Use this guide for configuring VR300 WDS.

@shreakh If you configure the SNMP settings in the modem's web interface, then you could use a MIB browser (Free Personal Edition from iReasoning) to check what are the parameters implemented and you...