@korn4ever The purpose of Gateway IP address (optional) is when this device is not your default gateway and its LAN IP address is static. For example. Lets assume that I have an ISP modem router with...

@Itai You can use Bandwidth Control instead of QoS for the same purpose. Here's a gude on how to configure this.

@TechForACompany So what would they need this 3-rd party router for ? If it's not so good for PPPoE connection and it's a wired router, they can just connect the APs directly to the VR600 (using...

@Geffers Nope, that can't be done either. Guest network can be isolated from your local network though - check VR600 v3 user guide - Chapter 8.2. Your older TD-W9970 has a different FW and these...

@Geffers VR600 only supports one SSID for 2.4GHz band and one SSID for 5GHz band (except the two guest SSIDs).

@TechForACompany To avoid the double NAT you could configure the VR600 as a modem only - here's a guide for that and a story. If the 3-rd party router can't support PPPoE connection type very well,...