Solved: How to connect tp-link modem to tplink router.

I doubt that lack of understanding has anything to do with you. The TP-Link 8616 is a modem/router combo, but even their user guide refused to say that anywhere. Its default LAN IP address is 192.168.1.1, and I'm guessing that's the same as for the other TP-Link router. Glancing through the manual I saw no way to bridge the 8616 (make it work as modem only), so you have two choices if I'm right about the LAN subnet used by the 1043. By the way, I could find nothing about that router, but did find information on TP-Link TL-WR1043N and TL-WR1043ND routers.

a. Change the subnet used by one of the routers; e.g., to 192.168.3.x.

b. JohnWill's procedure (Aug. 30, 2008) for configuring a secondary router as a switch and, optionally, wireless access point follows.

Connecting two (or more) SOHO broadband routers together.

Note: The "primary" router can be an actual router, a software gateway like Microsoft Internet Connection Sharing, or a server connection that has the capability to supply more than one IP address using DHCP server capability. No changes are made to the primary "router" configuration.

Configure the IP address of the secondary router(s) to be in the same subnet as the primary router, but out of the range of the DHCP server in the primary router. For instance DHCP server addresses 192.168.0.2 through 192.168.0.100, I'd assign the secondary router 192.168.0.254 as it's IP address, 192.168.0.253 for another router, etc.

Note: Do this first, as you will have to reboot the computer to connect to the router again for the remaining changes.

Disable the DHCP server in the secondary router.

Setup the wireless section just the way you would if it was the primary router, channels, encryption, etc.

Connect from the primary router's LAN port to one of the LAN ports on the secondary router. If there is no uplink port and neither of the routers have auto-sensing ports, use a cross-over cable. [You will not need a cross-over cable if one of the "routers" is a computer.] Leave the WAN port unconnected!

This procedure bypasses the routing function (NAT layer) and configures the router as a switch (or wireless access point for wireless routers).

For reference, here's a link to a Typical example config using a Netgear router