The PPP over Ethernet (PPPoE) subscriber session is established using the point-to-point (PPP) protocol that runs between the CPE and BNG. PPPoE was designed for managing how data is transmitted over Ethernet networks, and it allows a single server connection to be divided between multiple clients, using Ethernet. As a result, multiple clients in a shared network can connect to the same server from the Internet Service Provider and get access to the internet, at the same time, in parallel. To simplify, PPPoE is a modern version of the old dial-up connections, which were popular in the 80s and the 90s.
While IP over Ethernet (IPoE) subscriber session is established using IP protocol that runs between the CPE and BNG; IP addressing is done using the DHCP protocol. IPoE is essentially DHCP-triggered subscriber interfaces. • Users are "authenticated" through the use of DHCPv4/v6 Option-82 inserting their Circuit-ID into their initial DHCP Discovery - this identifies the physical location of the user based on the tail that they are connected to (this would be done at an aggregation switch between the xPON network and whatever backhaul gets them to their ISP of choice).
Let’s see how both technologies differ from each other by comparing them with the most known features as shown below:
Feature | IPoE | PPPoE |
Multicast | Multicast replication at an access node (Efficient) | Multicast replication at BNG (Inefficient) |
IPv6 | - 1:1 C-VLAN model has a well-defined IPv6 single-stack residential/business service model - No simple IPv6 single-stack solution in N:1 S-VLAN environment - Challenges in N:1 S-VLAN environment. | PPPoE has a well-defined IPv6 single-stack residential/business service model regardless of the aggregation environment |
Security | Poor any physical connection will have the access | Subscriber isolation(username/password) |
Authentication | Circuit-ID/MAC authentication | PAP/CHAP username/pwd(Allow full authentication of customers) |
Customer Control | Not simple | Allows control over customer connections (suspend accounts, create accounts, etc.) |
User tracking | No usage tracking built-in to DHCP (GB transfer) | Usage tracking (GB transfer) from radius generated data |
Overhead | Less overhead | 8 bytes MTU overhead |
Simplicity | Plug & play no need to touch the CPE from the customer | The customer has to enter his username/password |
Connectivity state | Lease timer | PPPoE keep-alive |
Wholesale support (LAC/LNS) | Needs a lot of work with limited options | Simple and a lot of options available |
Session Establishment | session-identifier uniquely identifies subscriber connection | Connectionless—use IP address as customer identifier |
