PPPOE vs DHCP

If using DHCP, RADIUS/AAA will authenticate the user, and then allow DHCP to happen, assign the address, etc. If I'm using PPPoE, the PPPoE session establishes, and the address is assigned via IPCP.








PPP includes a process for assigning Layer 3 attributes using network control protocols (NCPs). The NCP used to assign IP addresses within a PPP connection is IP Control Protocol (IPCP). IPCP is described in RFC 1332.


PPP has two drawbacks. First, PPP essentially uses two levels of L2 encapsulation. This adds 10 bytes to every packet. This requires more processing to create, inspect and terminate each PPP packet than is required by the simpler IP over Ethernet (IPoE) method.





IPoE relies on DHCP to provide the IP address. DHCP was designed to assign an IP address to a LAN-attached device.