Office Network Topology - Lack of connectivity to devices

Question

I am in the processing of setting up our office network. Unfortunately, I'm not very experienced in this aspect and am encountering several issues (possibly due to the same cause).

Network Diagram

The Devices

• 5x 4G Routers (Huawei) with WiFi and LAN
• 1x Load Balancing Router (TP-Link R480T+)
• 1x Router (TP-Link N900)
• ~12 PCs in Group 1, ~4 PCs in Group 1, ~20 phones/tablets in total for Group 1 and 2

Note: The #1 and #5 4G Routers have Static IPs which are necessary for certain VPN/Whitelist server access. The Load Balancing Router does not have WiFi and requires connectivity to another device for WiFi capabilities.

IP Addresses
My idea was to setup a series of IP Addresses as follows:

• 4G Routers :- 192.168.30.1 - 192.168.30.5
• Load Balancing Router :- 192.168.20.1
• Router: 192.168.10.1
• PCs and other Devices: 192.168.10.10 - 192.168.10.254

Note: I believe this setup might be incorrect and thus the cause. As I recall, all the networking devices have 255.255.255.0 as the subnet mask (I can check on this if need be).

The Idea
The idea is to allow any devices in Group 1 easy access to each other's machines. I intend to allocate preferred IP addresses from the available IP Range to the PCs and any other devices so that we need not check what someone's IP is (as caused by DHCP). Though the 4G Routers have WiFi, I intend to disable it such that all the devices in Group 1 are connected to the internet through the routers and thereafter through the 4G routers. Group 2's devices will connect directly to the 4G Router #5 (this may expand and follow a similar setup as Group 1 in future).

The Issue
A few other colleagues and I will be required to access the 4G Routers as well as the Load Balancing Router for monitoring/configurations/status-checks, etc. However, me pinging 192.168.20.1 (Load Balancing Router) from my PC does not work. Whereas, pinging the same address from the Router (N900 Router) works. However, any pings to the 192.168.30.1-5 range does not seem to work at all from the N900 Router or my PC. Traces also fail and doesn't seem to go beyond the originating device (1st hop).

The Question
What changes need to be made to allow for this setup to work properly?
Thank you in advance!

Answer 1

Every router needs to know where to route their packets. The N900 will send ping packets to the load balancing router with an IP address 'closest' to that router, so 192.168.20.X. The load balancing router knows how to route this, because it is directly connected. Your PC will send it's packets with a source IP address of 192.168.10.10. If the load balancing router is only configured with a default towards the Huawei routers, it will send any reply to your computer to the Huawei routers. It will never reach your computer.

What you need to do, is make sure that both the load balancing router and the Huawei's know where to route 192.168.10.0/24. They only need to know the next hop, So for the Huawei's, the 192.168.10.0/24 should point towards the 192.168.30.X address of the load balancing router. The Load Balancing router in turn needs a route for the same subnet to the 192.168.20.X address of the N900.

Note that the only reason to give the Huawei's a route for 192.168.20.0/24, is if you wanted them to be able to reach something on that network. They don't need to know this subnet to reach the computers.