Hello Donald
The terms “WAN support” and “WAN interface” can be misleading when we talk about devices capable of connecting to the Internet. They are often used loosely to refer to specific capabilities of a device.
The truth is that nothing prevents you from connecting your Layer 3 switch to the ISP and performing inter-VLAN routing between your WAN connection and your internal LAN subnets.
Some cheaper vendors that offer edge routers (sometimes xDSL or cable routers) will label their routed port as the “WAN” port. This is useful for those not as well-versed in networking. This is just a routed port, nothing more.
So what does it mean then when it says no WAN interfaces? It simply means there’s no dedicated interface to be used with the WAN, that may have some predefined policies or mechanisms suitable for connections to the ISP. It may also mean that it doesn’t support some additional WAN physical interfaces such as xDSL, Cable, T1/E1, Serial, or others…
What does it mean when it says it doesn’t have WAN support? This is a bit more vague, and depends upon what the vendor considers WAN support. It typically means that the device does not support WAN protocols such as PPP, HDLC, Frame relay or other similar ones. It may also mean that QoS features are not available, or that some routing protocols typically used at the edge of a network, such as BGP may not be available. To determine what it actually means, you must take a closer look at the vendor’s documentation.
I hope this has been helpful!
Laz