Least expensive wired-only gigabit router? (TP-Link Festa FR205? Others?)

[Bill_Stewart]

For the curious, a brief overview:

---

               +----------------+    +-----------------+
               |   DSL Modem    |    |    L2 Switch    |
               | 192.168.0.1/24 |    | 192.168.1.3/24  |
               +-----------LAN--+    +--1--2--3--4--5--+
                            |           |           |
                            +--VLAN 10--+           |
                                                    |
                                 +----VLAN Trunk----+
                                 |
                                 +------------VLAN Trunk------------+
                                                                    |
    +-----------------------VLAN 10------------------------+        |
    |             +------------------+                     |        |
    |             |           +------|---------------------|--+     |
    |             |           |      |      +--VLAN 10--+  |  |     |
    |             |           |      |      |           |  |  |     |
+--WAN-----------LAN--+   +--LAN----LAN----WAN--+    +--1--2--3--4--5--+
|    Wired Router     |   |     WiFi Router*    |    |    L2 Switch    |
| LAN: 192.168.1.2/24 |   | LAN: 192.168.1.1/24 |    |  192.168.1.4/24 |
| WAN: 192.168.0.2/24 |   +---------------------+    +-----------------+
+---------------------+  *LAN static route: 192.168.0.0/24 -> 192.168.1.2

---

The DSL modem runs in "transparent bridging" mode, and it has an assignable LAN IP address. It is physically separated from the wifi router to optimize wifi coverage. Currently the connectivity between the two devices is a pair of powerline adapters. (The powerline adapters are not a bottleneck currently because their throughput exceeds the current Internet bandwidth.)

The goal is to be able to access the DSL modem's web-based configuration interface from the "main" (primarily wifi) network (192.168.1.0/24). The problem is that I can't assign the DSL modem an IP address on the same network ID as my main network (192.168.1.0/24), because this means the wifi router's WAN and LAN interfaces are on the same network (this doesn't work).

The fix was to create a separate VLAN and network ID for the WAN side of the wifi router and LAN side of the DSL modem (192.168.0.0/24 on VLAN 10). To reach the DSL modem's configuration interface (192.168.0.1), a static route is required as shown in the diagram. This configuration prevents the wifi router's LAN and WAN interfaces from being on the same network, and the static route and wired router provide access to the 192.168.0.0/24 network from the 192.168.1.0/24 network.

 

[Tech9]

I don’t see what’s the problem accessing the modem’s interface without all this complication.

 

[Bill_Stewart]

I don’t see what’s the problem accessing the modem’s interface without all this complication.

I can't connect both the wifi router's LAN and WAN interfaces to the same network ID. When I do that, the wifi router gets very confused; this causes all kinds of weird connectivity issues, and the DSL modem's LAN side is not accessible. The only way I was able to make it work was to put the wifi router's LAN and WAN interfaces on two different networks.

 

[Tech9]

I can't connect both the wifi router's LAN and WAN interfaces to the same network ID.

I’m a bit confused. Does the above mean your main Wi-Fi router has private WAN IP 192.168.0.x? If yes - what’s the transparent bridging on the modem for and what is stopping you from accessing 192.168.0.1 upstream? Perhaps I don’t know some modem related specifics.

 

[Bill_Stewart]

Does the above mean your main Wi-Fi router has private WAN IP 192.168.0.x?

The wifi router's WAN interface gets a public IP from the ISP (this is the purpose of the transparent bridging mode of the DSL modem (the DSL modem is not in "router" mode).

I see the confusion because I actually stated this somewhat imprecisely (but it shows in the diagram): The wifi router's WAN interface and the DSL modem's LAN interface are on a different VLAN than the rest of the network.

 

[Tech9]

Got it, still modem specifics. I have a few cable modems in bridge mode and they have accessible management interface on 192.168.100.1 with connected to them routers getting public WAN IP.

 

[Bill_Stewart]

I think it has something to do with how the wifi router handles things when its LAN and WAN interfaces are in the same broadcast domain. Things get weird when that's the case. When I segment the LAN and WAN interfaces onto separate VLANs and separate network IDs, things work perfectly.

 

[sfx2000]

I think it has something to do with how the wifi router handles things when its LAN and WAN interfaces are in the same broadcast domain. Things get weird when that's the case. When I segment the LAN and WAN interfaces onto separate VLANs and separate network IDs, things work perfectly.

On the WiFi router - remember that it can be a router or just an AP...

Depending on the router vendor/model, it might have "AP Mode" - which turns off the routing, firewall, and DHCP/DNS services, but keeps the ethernet and wireless interfaces active...

The internal switch inside the AP should honor the VLANID tags...

LIttle Tip here - when assigning VLAN ID's, use values above 100, as ones below that are sometimes used for internal VLAN's...

 

[Bill_Stewart]

On the WiFi router - remember that it can be a router or just an AP...

Since my DSL modem is running in transparent bridge mode (i.e., not as a router), my wifi router runs as a router rather than simply a wireless access point.

LIttle Tip here - when assigning VLAN ID's, use values above 100, as ones below that are sometimes used for internal VLAN's...

For my little home network, the secondary VLAN ID doesn't really matter. If it really does need to be changed at some point, that's simple enough to do.

 

[Tech9]

Interesting workaround and hey… if it does what you need it to do and with little expense - why not?