New Wifi Router on Old ADSL Modem/Router

Is there a requirement to contact your ISP and "register" or otherwise have the new router activated?

In any case, it would be worth a call to them to learn what they can see and tell you with respect to having the new router connected.

So you wish to have one network as wired and the other "new" network to be wireless....

And the connectivity is to be:

ADSL Splitter ---------> (ADSL port)Cable Modem/RTA01N (LAN port) ---------ethernet wire ---------> Router/Xia0mi (LAN port).

Does this user manual match your modem?

http://www.movistar.es/rpmm/estaticos/residencial/fijo/banda-ancha-adsl/manuales/modem-router-inalambricos-adsl/Router%20ADSL%20Observa%20RTA01Nv2/user-manual-router-adsl-rta01n-observa-v2.pdf

Nature of the beast....

I asked because the configuration process can be a bit overwhelming, complicated, and tricky. Especially if the manual is not that well-written or kept fully up-to-date. Or there is an inherent expectation is that "we should somehow know" bordering on the clairvoyant.

You planned setup is as would be expected. The most important part is to ensure that the modem's DHCP is off. What could be happening is that modem is "remembering" the old router and not recognizing the new router. I have read about that a few times here and there. Suspect that that may be the situation with respect to your router swap.

Basically needs a reset and do-over.

The modem will need to be reset, reconfigured (e.g., turn off DHCP, set IP address) and then again connected to the ADSL via the splitter/filter. You will need to wait until the modem reports it is connected to the ISP via the green indicator. May require a few minutes to accomplish that. If connection does not succeed then you will need to dig into process and settings/troubleshooting to see if some step or configuration requirement was missed or made in error. Fortunately you do not need, or will not need, most of the functions inherent in the modem. Just leave the defaults as they are unless a specific change requirement is necessary.

As for the IP addresses I would leave the router at 192.168.1.1 as all the network devices know that. The modem's IP should be changed during the modem's reconfiguration to 192.168.2.1 as you mentioned. Not sure that that is the best choice per se and I will defer to any other recommendations or suggestions.

Once the modem is up and connected to the ISP then, yes, the ethernet cable goes from the modem's ADSL port to the router's WAN port.

It may take a few minutes for the modem and router to handshake and get themselves set accordingly.

Some things to be ready with in advance: The respective/default IP address for both the modem and router's admin webpages along with their login name and password. All should be the defaults after a factory reset. A known working ethernet cable suitably long to reach directly from your PC to either the modem or the router. Direct connectivity is needed for configuration. Try to have the ablility to do a screen capture and print while working in the device home pages. Very helpful to record settings both before and after.

I also suggest a simple SOP of your own to identify the things that need to be done and the order in which to do them. Just your own little "step-by-step" procedure that can reference user manual pages. Just doing your own little procedure will help you learn and identify questions beforehand. You will learn and it all will get easier.

Preplan/select your settings when you get to make the choice. E.g., SSID, password,wireless security.

Please post any further questions or concerns. Thanks.

The new router already has its address (192.168.1.1) which is the default address. (Actually one of default IP addresses available for private networks.

Do not change the new router's IP (192.168.1.1) as all of your devices are looking to the new router to get an assigned DHCP IP. You are moving that DHCP IP assignment function from the ADSL modem to the router. As you mentioned "The new router works great with the clients in the house (NAS, Amazon Fire TV box, phones, tablets, PCs etc), the speed is hugely improved." Leave that all alone.

However, you must set up the ADSL modem (RTA01N) so its IP does not conflict with the router. Which, as I understand your posting, the ADSL modem is to be 192.168.2.1.

Page 73: DHCP Configuration = None: You do not want the modem to being doing anything DHCP.

Page 74: Probably not although I can see how it could be read that that is where you could enter 192.168.2.1 for the LAN address and the MAC address of the new router in "MAC address".

Look at page 31: If your modem (RTA01N) only has one ethernet port as show in the introductory pages then that, in my mind is where the 192.168.2.1 (submask 255.255.255.0) should be assigned.

Specifically the IP address under "Interface Name :Ethernet1" being 192.168.1.1 and you will be changing it to 192.168.2.1

If you reset the modem and 192.168.1.1 appears there (Ethernet1) then I am thinking that Ethernet1 is probably the correct configuration point for the change.

And if my Page 31 reasoning fails, then page 74 can be the fall back attempt. Or vice versa, you have certainly worked on it all more. No harm or insult if you try Page 74 first.

The manual instructions unfortunately are going to make it all a bit of trial and error.

However, once you make the initial modem settings (including the IP change to 192.168.2.1) and have the green light showing ADSL connectivity you shoud be able to connect the modem's ethernet port to the router's WAN connection. Give it some time to work/handshake. Then you should at least be able to get to the modem webpages (via browser and 192.168.2.1) and not have to do any more resets. Some changes may require restarts.....

Pretty much that is the way I would go about it all. Please post what happens. Thanks.