For Ethernet Backhaul - WAN vs. LAN - Nest Pro - 3 questions

[gsgallant]

I am setting up a partial ethernet backhaul for Nest pro.   I have a large home and I have 5 units.

Nest Pro Main is set up to the FIOS modem using the WAN on the main nest pro as expected.

The LAN on the main nest is connected to a switch for multiple devices including another 2 Nest Pro units.

1. Does it matter on the 2 other Nest Pro units whether I use their WAN or LAN for the configuration I have described?

2. Also, if I want to add another switch on one of the satellite Nest Pro units then I am assuming that this must be from that unit's LAN port, correct?

3. Also, since this will be a mixed backhaul system (3 connected via ethernet and 2 via wifi) I am assuming that this is acceptable and should not create issues for me.  Please confirm.

Thanks.

[MichaelP · Accepted solution]

Hello @gsgallant 

I'll try to answer these as best I can.

1. On secondary/point units, you should be able to use either the WAN or LAN Ethernet port to connect to the switched Ethernet network. Those nodes are in "bridge" mode, so both ports are part of a virtual switch internally. However, I would pick one and stick with it consistently (don't move the cable from one port to the other without restarting the network, just to be safe).
2. You can add another switch downstream from a wired secondary, but I would personally recommend building out a switched network and then hanging any wired secondaries off of it rather than trying to use them as two-port bridges, since any traffic through that node will be handled in software compared to a dedicated wired switch. 
3. Building mixed wired and mesh systems can be a little tricky. The mesh protocol doesn't run over Ethernet – it only runs on the 6GHz WiFi radios in the units. So, when a unit is wired, it essentially withdraws from the wireless mesh. This is important, because it means a wired unit does not act like a "base station" for a more distant wireless mesh connected unit. To make this work, ensure any wireless-only secondary units are placed no more than one or two rooms away from the primary/router unit (especially important while we're still waiting for the FCC to allow higher 6GHz transmit power). Wired secondaries can be placed further away. Basically, you're building a wireless mesh system, following the best placement advice for those nodes, and then also building a wired system.

In addition, I would caution against using "smart" (managed) Ethernet switches in a system with wired secondaries. This can be made to work with proper configuration, but it's much easier to deal with simpler (and cheaper) unmanaged switches.

[gsgallant]

Thank you for the careful and complete answer.

Based on #3, in your answer, I am now thinking that an ethernet backhaul is not only unnecessary but is actually disadvantageous if I can create a 'great' mesh network without the ethernet connections.  "Great" is the rating given by the "Mesh Test" on Google Home when the mesh is strong.

Is my assumption above correct?

[MichaelP]

Honestly, I really like using Ethernet to connect secondaries. It is a bit more reliable than WiFi, lower latency, and doesn't compete with client traffic in the same band. But, as long as you can build a complete mesh with all of the secondaries no more than one or two rooms away from the primary, and all get "great" mesh test ratings, then it should be fine as well. You may find you don't need 5 total units to get good coverage in that case, though. Ethernet lets you push the secondaries further away from the primary, which expands the coverage area (to, for example, the front and/or back yards).

[gsgallant]

Wonderful.  Much appreciated again.

[gsgallant]

I did an experiment and found that when I had Ethernet as a backhaul the mesh test showed “good” for that node.  

When I removed the Ethernet and restarted the network, that node showed “great” for the mesh test.  

Any clue why that would be?

[MichaelP]

That typically happens when the Ethernet connection is only able to negotiate and maintain 100Mbps rather than 1Gbps connectivity. I would check the cable run and ensure any switches. You can debug by connecting the secondary directly to the switch through a short, known-good Cat 5e cable and re-running the test (move the node into the same room as the switch if needed for this test).

[gsgallant]

Thanks for the quick reply.

The switch is 1GB rated and the cable runs are all CAT6.

[MichaelP]

Cat 6 cables can sometimes still fail to negotiate a 1Gbps connection, which requires all four wire-pairs to have a solid connection. If even one of those eight wires doesn't connect well, it will drop back to 100Mbps. Oddly, this can be more likely with Cat 6 cables than with Cat 5e cables, since Cat 6 cables are often stiffer, and any bend in the cable near a port can result in one or more wire-pairs not making a reliable connection. So, I'd still perform the testing I suggested above (short, known-good cable in the same room; then build the system back up one piece at a time).

[gsgallant]

Fantastic information and much appreciated.

I'll be doing some troubleshooting and experimenting per your advice.

In the meantime, I have eliminated all the ethernet backhaul connections and I am getting "Great" on all 5 nodes.  I have a switch on two of the nodes (connected to the LAN port on the node) and using if for various devices.

The network is strong and the devices are working well - TV streaming, video conferencing on computers, music streaming, etc.   It appears that my concerns over the need for ethernet as a backhaul were unfounded and I have this thread and your sage advice to thank for that.

Thanks again.