Both clients in AP client router mode need a subnet IP for the LAN network which is different from the WAN subnet IP, e.g. it should use the 192.168.x.0 subnet, where x is a number between 1 and 255. For example, set the CPE's IP for the LAN to 192.168.1.1 (both clients can use the same IP, but it won't harm if they are different, too). Their WAN IP is dynamic according to your topology (I would use static IPs, but YMMV). Anyway, the LAN subnet must be different from the WAN subnet of the client APs (WAN = wireless network, LAN = wired network).

tplink_cpe510_user wrote

No to disagree with @R1D2, however, in setups I have deployed, I have always used fixed (or statically assigned DHCP issued addresses) for the equivalent of your CLIENT CPE510 devices.

Before thinking of assigning IPs, you have to choose the operation mode. In WISP operation mode (that's what AP client router mode is for), your CPE behaves as a router, its WAN is a wireless client and its LAN includes an additional wireless AP (meaning the router's LAN will be distributed wirelessly, too), thus two separate networks, all in one CPE.

Since the CPE is routing, you have to have two networks: LAN and WAN. On the WAN side you connect to the central AP's wireless LAN. The central AP's wired WAN often is a third network connected with an Internet router's LAN (mode AP router), but could be also directly attached to the Internet router's LAN (mode AP). In the first case, the Internet router's LAN and the central AP's wired WAN are one subnet. The central AP's wireless LAN and the client's wireless WAN are another subnet, a so-called transfer network. The client's wireless AP and wired LAN, which are bridged, is yet another subnet.

You can't use the same subnet IP on those three (or two if the WISP AP is in AP mode) networks at the same time. This is the network topology with CPEs in AP client router mode connecting to an AP in any mode:





There are many good reasons for using such an operation mode:

- Different broadcast domains don't waste precious wireless AirTime on the client side of the CPE,
- wireless link between clients and WISP AP is used for Internet traffic only,
- LAN networks are isolated against each other (routing still allows inter-network connections if needed),
- WISP provider can separate data streams further, important for accounting/billing.

The possible problem is that the total limit of devices and systems in this combined environment is limited to 254 (assuming a subnet of 255.255.255.0 or /24).

This is no problem in your client/AP setup if you would use another netmask and IP range (e.g. 10.0.0.0/8). But I doubt that you will be happy with more than 30-40 wireless clients or more than 70-100 LAN users simultaneously accessing the Internet over a 200 Mbps wireless link (and that's max. rate in 802.11n-only mode if you get the full 300 Mbps wirelessly, where 200 Mbps speed is half-duplex, thus only 100 Mbps in one direction on the full-duplex cable of the Internet router). What's more, this are the total figures for all networks connected to one and the same WISP AP.

A simple test would be to setup a laptop to work with a static IP address, subnet and gateway on the LAN network of the ROUTER (for example use an IP of 129.168.0.3 in your case), then take that laptop over to the LAN of one of your CLIENT CPE510's (with differing IP address, as stated in my previous posting) and plug it in --- the laptop should still work and access the internet!!!!!

No, it won't work if the CPEs are in AP client router mode as outlined in AmariusB's network topology above. His CPEs are routing.

AmariusB wrote

Strange was that the setup was not working at all with the configuration specified in the instruction manual.

It works fine if correct subnet IPs are assigned as outlined in the instruction manual (your assignment was wrong for CPE's client router mode). Indeed, client mode is easier to set up if you want one big network, not just Internet access.