Mesh routers with auto sensing WAN/LAN ports problems with Fios ONT
Enthusiast - Level 3

I do not use Fios TV, only internet; 1gb plan. Years ago I successfully (and easily) swapped out the VZ router to my own (Tp-Link C3150). Two years ago, I successfully (and easily) swapped that router out for an Amplifi Alien. This past weekend I tried to swap the Alien for a TP-Link Deco XE75 Pro which has self sensing WAN/LAN ports and I could not get it to function correctly at all.

After hours and hours of troubleshooting (literally ALL DAY and I'm pretty well versed in doing this) I finally came across numerous reviews and threads of many users who are having the same issue not only with TP-Link but with Asus mesh systems which also have auto sensing ports. Again, this seems to apply to Fios customers who use their own router connected directly via ether from the ONT, that do not use the cable service. A work around I read about for the Asus was to put a 1gb switch between the ONT and the Asus; not sure if that would work with the TP-Link as I got too frustrated, sent it back and hooked back up my Alien. I know there is always the work around of having another router in bridge mode but that's annoying so I'm just really curious if anyone has any insight as why the ONT and self sensing WAN/LAN ports seem to not get along?

1 Reply
Community Leader
Community Leader

It's hard to say. This sounds like a firmware design issue to be honest. Although it's possible that something in the way Verizon's network works (Proxy ARP usage for example) makes the node think it is attached to the LAN.

Are you using wireless mesh between the rest of your mesh nodes, or are you making use of Ethernet backhaul? I've had problems even with systems like Linksys Velop even on DOCSIS (Cable) connections, whenever Ethernet backhaul is used between the mesh nodes. There's an order of operations at play with those Linksys devices, where the WAN link has to come up first, before the rest of the network comes up.  Which is a problem, because a simple network switch boots up and is ready to go in a couple of seconds, long before an ONT or Cable Modem is even ready to begin supplying Internet.  If it gets into the confused and broken state, you have to wait for the modem to come up, THEN restart the primary node in the network acting as the Internet Gateway. Sometimes a modem reboot is needed, and the modem has to come online before the Gateway unit is booted.

Another strange behavior I've seen with those Velop units, is where the router, even with auto-sensing ports, still randomly decides to send LAN traffic out to the WAN, which ends up crashing the mesh node because of all of the ARP traffic it sees. Again, I've seen this even on DOCSIS connections.

So as a result, I'm personally not a fan of anything with auto mapping ports. Have to be able to map WAN to a designated port that is ALWAYS the WAN no matter what. I think the mesh systems are just sometimes designed to be too simple, and likewise end up becoming too broken.