Question on Topology

[wel2024]

Hello,

Current plan: modem -> router ->(long ethernet run outside)-> switch -> Nest Wifi routers/APs

Which port should I plug in the ethernet connection to the mesh wifi router from the switch? I'm assuming the WAN....  Any specific configuration/issues I should look out for?

Thanks!

[MichaelP]

Hello @wel2024 

When you say "router" in the above, do you mean your primary Nest WiFi Router unit? Or are you referring to a third-party router?

If it's the former, then the above topology should work fine. But, if it's the latter, this will not work. The primary Nest WiFi Router unit acts as the firewall and creates a new "inner" network that all of the secondary/point Nest WiFi units must connect to. So, any Ethernet switches must be downstream from that primary, connected to its LAN Ethernet port (the one with the "<->" icon). You can't connect a mix of primary and secondary Nest WiFi units all to the same "outer" network created by a third-party router.

The only other advice I would give is to avoid using smart/managed Ethernet switches, since they usually have loop detection (spanning tree protocol) enabled, which interferes with connecting secondary Nest WiFi Router units via Ethernet.

As for ports, as I said above, the "inner" network is provided through the LAN Ethernet port on the primary Nest WiFi Router unit, so the WAN Ethernet port should be connected directly to the modem – not through a switch. On secondary Nest WiFi Router units (or Google WiFi units) added as points, connecting them via Ethernet can be done through either port, since they are all in bridge mode. I personally like to pick one and stick to it for consistency, though.

[wel2024]

Thanks for the thorough response!  To clarify, yes it's another third party router connected to the modem. The plan is to keep that router and network the same in the house, as it has multiple ports/connections that the Google routers do not have, then have a long Ethernet run outside and connect to the switch. From the switch ideally we'd have several cameras that connect back to the network inside, and then the primary Google router connected as well, giving the outside its own wifi network, (and own RFC1918 subnet), with the two other APs connected to the primary Google router to create the mesh, all on the same outside network.  You're saying that won't work? 

[MichaelP]

Ok, so you want to create a new Nest WiFi network inside the one already created by your existing router. Also known as "double NAT" due to the two layers of NAT firewalls between devices on that network and the internet. That may work. But, you need to make sure the primary Nest WiFi Router unit's WAN Ethernet port is the only thing connected directly to your existing network. Any other Nest WiFi units must connect to the new network created by that primary. As long as those are Nest WiFi Point units, that's what they will do, since they don't have Ethernet ports.

So, building all of that will work, but there are a few caveats. First, make sure you do not use the same WiFi SSID for that new network as your existing network. That will make your devices confused, since they are two different networks with different routers, different IP address ranges, etc.

Second, since the Nest WiFi Router is a firewall, there will be significant limits on connectivity across those two networks. Devices on the Nest WiFi network can get to the internet just fine. But, nothing in the existing network will be able to connect to anything in the new network.

Third, related to the above, since these are two separate networks, any dynamic discovery protocols (mDNS typically, though there are others) will only work within the scope of each network. You can't discover devices across them.

With all of that said, if all you're doing is trying to build a new WiFi-only network outside for some cameras (and maybe also configure your mobile devices to be able to connect to when they are out there), and you make sure it has a separate WiFi network name + password, I think this will work.

[wel2024]

Again, thanks so much for taking your time to respond to my questions! You are the best!  I will ensure the SSID is different outside as well as the subnet.  

The cameras outside I'll connect directly to the switch, so they will be on the same network as the inside router. Basically the outside wifi network will just be for phones, maybe a laptop, but I understand, nothing will be able to communicate to the inside resources from that outside wifi network (no problem there). 

Thank you!