Hello,

In order to extend my WIFI coverage I have recently added a new Access Point to my installation.

As I had a spare TD-W8960N I decided to use it for this only purpose (I followed the guidelines of the page https://www.tp-link.com/it/support/faq/417/), gave him a static IP Address and disabled both IPv4 and IPv6 DHCP servers on it.

My network set-up is the following:

[Main Router] //TP-Link TL-R480T+ 
192.168.10.1
  |       
  ├── /* Ethernet devices */
  ├── Wireless Access Point #1 - 192.168.10.15 - SSID1 //TP-Link TL-WA901ND
  └── Wireless Access Point #2 - 192.168.10.10 - SSID2 //TP-Link TD-W8960N  <- New AP 
        |       
        └── /* Some devices connected with Ethernet cables - working fine */

Main Router is the one and only DHCP server, giving IP addresses between 192.168.10.20 and 192.168.10.200.

Everything seems to work fine except when one mobile device, connected to SSID1, tries to connect to SSID2.

Then strange things start to happens :

• sometimes it works perfectly, the network changes and my mobile device can access internet
• sometimes it works, but obtaining the address can take a couple minutes
• sometimes it fails, my phone showing a "Failed to obtain IP Address" message, if it fails several times in a row, switching off and on the TD-W8960N seems to fix the problem

Also it's important to notice that when coming from SSID2 to SSID1 (managed by TL-WA901ND) it always works fine. 

What I have tried so far:

• I have updated the main router DHCP configuration to give a static IP to the mobile device. This way it seems to never fail but most of the time it takes a couple minutes to obtain the IP address (which btw stays the same). 
• I have updated my phone configuration to use a random MAC address when connecting to SSID2. This way it always work perfectly and I obtain an IP extremly fast, but I have the feeling that this not a clean solution.

My feeling is that there is somehow a problem in the way the TD-W8960N  handle the DHCP configuration coming from the main router but I can't find what has to be done to set it up correctly. 

Any clues will help.

Thanks