I can’t agree, and I think you missed some key aspects. The multiple connection / interface ideas here are not relevant. Yes you could put a complicated mess of switches in front of the Pep, but in that case it would all be static addressing, and the Pep is not directly pinging the ISP for an address. The Pep WAN node offers one (1) only WAN setting, with one (1) only optional VLAN # per WAN port. The Pep makes a DHCP Discover/request and gets a response Offer (which it ignores here). On the WAN side, the Pep is always the client. If a current DHCP address is terminated and a new one is offered, then how is that different from a non-VLAN’d setup? Its not. The Pep will only ever have one valid DHCP assigned address on that WAN port, and only 1 VLAN #. The device connected to this WAN port is a bridged ISP modem, with thousands of connected clients, and clearly they keep everyone isolated. Now ISP modems that segment services by VLAN, do so under one IP address. I don’t see how you can have two Pep WAN ports combined into the one bridged connection.
And I say again, every dumb and cheap router I have tried under these conditions connects up and works… so why can’t my Pep do the same?