This can mean that your router is detecting a Static IP. Have you asked your ISP to provide you with a Static IP?
Also, what's your current configuration? And, are you facing issues while connecting to the internet?
As far as PPPoE is concerned, it stands for Point-to-Point-Protocol over Ethernet. PPPoE relies on two widely accepted standards: PPP and Ethernet. It is a specification for connecting the users on an Ethernet to the Internet through a common broadband medium, such as a single DSL line, wireless device or cable modem. All the users over the Ethernet share a common connection, so the Ethernet principles supporting multiple users in a LAN combine with the principles of PPP, which apply to serial connections.
I have the WAN connection type as PPPoE in my router configuration.