Turning my Optilink XONT71110N Modem into a router

I have an Optilink Modem which used to be the modem for my G-Internet connection (Bangalore, India). I currently am using Hathway Internet Connection which covers all areas except our bedrooms. While the placement of the router is a totally different issue, I am looking for a list of instructions specific to the Optilink Modem (model no. as written in question title) which I find for TP-Link instead. The layout and the wordings of the settings are different for different routers. Since I'm not conversant with TCP-IP etc, adapting an instruction manual for one router to another is not easy for me.

Two things I did learn:

1. If the intended router supports Bridge mode it is helpful
2. The IP Addresses of both the current modem and the router are required.

Points 1 and 2 were easy to do. The former is very easy while the latter was achieved on my ubuntu machine through the

ifconfig

command on my Ubuntu machine.

There are several Tabs in the settings. My guess is that the "Network" Tab is the relevant tab to refer so I have attached all the screenshots of the home pages of the submenus of the "Network" menu.

Network >> Internet

Network >> Binding (editing in this page is disabled)

Network >> LAN IP Address (I'm guessing this is the relevant tab, going by whatever I've read. The homepage is the IPv4 settings which I figure is the one we need to modify. Apart from IPv4 there are 3 other menus and all 4 are on the left panel)

Network >> WLAN (This also could be the place to modify settings, whether it's basic, advanced or one of the other two in the left panel)

Network >> Remote (This might not be relevant but just in case)

Network >> LOID Configuration (No idea what on earth that might be!)

Network >> Rouer (This is of strong relevance and I expect some modifications to happen here.)

Here are the IPv6 settings

Click here

I can edit the question and remove the irrelevant ones. Any help is appreciated.

I tried changing the WLAN Security settings to WPA2 just like in my internet connection and I set pre shared key, which is a passphrase (not HEX) but once i do that I'm unable to connect to my old modem again.

You're saying that you want the Optilink only for Wi-Fi coverage. In this case, you don't want it to be a router – the job of a "router" is to connect separate IP networks, but for you it's better if everything stays one large IP network, as this will allow you to use the same SSID on both modems and have all your Wi-Fi devices seamlessly roam from one to another.

^{(They're called "wireless routers" because they had wireless added onto a wired router – not because routing had anything to do with wireless.)}

1. In the "LAN Settings > IPv4" page, completely disable the DHCP server.

   

2. In the same "LAN Settings > IPv4" page, change the Optilink's IP address to something that would be within your main LAN's network, but also wouldn't conflict with e.g. the Hathway gateway's IP address. For example, if the Hathway is 192.168.1.1, make the Optilink 192.168.1.4 or something.

3. In "LAN Settings > IPv6", disable DHCPv6, SLAAC, RA, and similar.

4. Recommended: In the Wi-Fi page, change your SSID (under "Basic") and security parameters (under "Security") to be the same as your main Wi-Fi network's.

   Devices will automatically switch between Wi-Fi access points that have the same SSID. But if you actually don't want this, feel free to keep the SSIDs different.

   

5. In other settings pages, I would disable TR-069 completely.

6. If you find UPnP or IGD in any of the settings pages, make sure to disable that too.

7. Finally, connect one of the Optilink's LAN ports to the Hathway gateway's LAN.

If the intended router supports Bridge mode it is helpful

It is somewhat helpful, but not mandatory. The fact is that most routers already have a bridge that covers the Wi-Fi and the wired LAN ports, and this will do the job.

Usually, having explicit "bridge mode" support in a router just gives you one extra Ethernet port (the one previously meant for WAN, but now part of the same big LAN bridge), and/or possibly makes it easier to disable features that were needed for a router but are no longer needed for a pure bridge-only device (but in some cases it might not actually make things simpler).

The IP Addresses of both the current modem and the router are required.

Points 1 and 2 were easy to do. The former is very easy while the latter was achieved on my ubuntu machine through the ifconfig command on my Ubuntu machine.

ifconfig only shows the IP address of your own computer, not of any router/modem/gateway.

The router's address (i.e. the actual gateway between your LAN and the internet) can be found in ip route or netstat -rn, under the "default" route.

Network >> Remote (This might not be relevant but just in case)

TR-069 allows the modem to periodically "call back" to the ISP and receive new configuration. I would disable the 'Interval' and remove all parameters, to avoid the modem accidentally picking up unwanted configuration from the ISP.

Network >> LOID Configuration (No idea what on earth that might be!)

The Optilink is a GPON fiber-optic "modem" (ONT), so the LOID is how it identifies itself to the GPON OLT sitting at your ISP. As far as I understand it, it's pretty much like a username (together with the password).

(The physical GPON line is actually shared between several customers, they all need unique identifiers so that the ISP would be able to assign them IP addresses and speed limits – either the modem's serial number or a "LOID" + password are used for this.)

Network >> Rouer (This is of strong relevance and I expect some modifications to happen here.)

On the contrary, it's completely irrelevant to your goal of getting better Wi-Fi coverage.

(Routers connect networks/subnets, and RIP is a mechanism to automatically exchange routes among multiple subnets without having to manually define each path on each router. However, on small home networks it's almost never useful, and networks that become large enough to need it, will usually go straight to better methods.)