Airport Express - why WAN port?

[komatsu]

Setting up an Access Point

When connecting an access point (e.g. TP-Link) to a standard modem router, it is always recommended that the connection from the modem-router goes into one of the LAN ports.

modem router - > access point (LAN port)

But with the Airport Express it seems, it is recommended that the connection from the modem-router should be connected to the WAN port (of the AE)?

modem route - > airport express AP (WAN port)

Why is this?

 

[FreakinEurekan]

¯\_(ツ)_/¯ why not?

The AirPort Express is capable of being configured as either a Wireless Access Point or as a Router/Access Point, so it has a WAN port. Makes sense to use that as the "Input" regardless of how you're configuring the Express. A pure Access Point (without Router features) would not even have a WAN port.

 

[mac8867]

Your post is a bit confusing. A Modem and Router are two different things. (Even though some devices combine the functionality into one box).

Modem: Communication with a remote network (ISP in most cases)
Router: Traffic routing and distribution to a network
Access Point: Wireless propagation to extend reach of a primary wireless network
Switch: Traffic distribution within a network (does not route)

So, "routers" have WAN ports so they can be connected to a "modem". If a device, labeled as an access point has a WAN port, it has routing capabilities (from and to that port).