What is PPPoE – Point-to-Point Protocol over Ethernet

April 21, 2023 By Christine Margret No Comments 5 minutes

This blog will discuss PPPoE, which stands for Point-to-Point Protocol over Ethernet. The PPPoE is a network protocol. It is mainly used on serial links.

What is PPPoE

However, ISPs also use PPPoE as the data link protocol over many broadbands DSL connections for the remote assignment of IP addresses. It is also used for CHAP authentication to check customer account records.

However, ethernet doesn’t natively support PPP. So, to configure it, we use PPPoE, which is called Point-to-Point Protocol over Ethernet. Let’s get into the details of PPPoE below.

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What is PPPoE?

PPPoE is a network protocol derived from an old communication protocol called PPP. The PPP protocol provides data authentication and transmission on a network. However, PPPoE is its modern version and works for many users simultaneously with the same functionality.

Basically, PPPoE encompasses PPP with the Ethernet link layer protocol. The PPPoE is used for LAN users and combines the security features of both Ethernet and PPP.

The PPPoE protocol controls data transmission over the cable. Another quality of PPPoE is that it divides the single server connection between multiple users.

Consequently, multiple users use the same network servers and connect to the web simultaneously.

How does PPPoE work?

As outlined above, Ethernet and PPP don’t have native support for each other. Therefore, to create a supported multi-host environment, we can use PPPoE.

PPPoE facilitates a point-to-point relationship between network peers. It covers the gap between Ethernet and PPP.

A local multi-host Ethernet network uses PPPoE to share PPP sessions with various destinations through one or more bridge or access concentrators.

PPPoE functions at the network access layer in the TCP/IP and at the data link layer in the OSI model.

This Protocol is basically designed for broadband technologies to use for bridged Ethernet connections.

PPPoE is cost-effective, gives network providers complete access control, and manages session abstraction.

The PPPoE communication operates in two stages: The PPPoE discovery stage and The PPP session stage.

The PPPoE Discovery Stage

In the PPPoE discovery phase, the client’s system forms a communication channel using an access concentrator. The PPPoE server arranges and authenticates the connections via the PPPoE clients. These PPPoE clients follow a series of steps, then find a local Ethernet MAC address and then form a session ID. This session ID is used throughout the session.

The PPPoE Session Stage

Once the discovery stage is completed, and a connection is established, the access concentrator and client move to the session stage.

In the session stage, Point-to-Point communications between the client and Access Concentrator are established. After establishing the connection between the host and the server, the PPPoE transfers data. Each user now connects to the internet, while PPP protects the entire connection.

What is the Benefit of PPPoE – Why do we use it?

PPPoE is beneficial for ISPs. In case your ISP uses PPPoE, then they can easily manage the internet connection with the following:

Assigning you a unique ID (username and password)
Assigning you a modem router that connects you with your ISP’s internet network.

Note: You must manually configure the PPPoE connection if you don’t have a router.

How to Configure PPPoE?

To manually set up the PPPoE connection, you will need the PPPoE username, password, and MTU size ( maximum transmission unit ).

Your ISP will provide the username and password, but your administrators should provide the MTU size.

Networks should be appropriately configured with the right MTU size to function correctly. The standard MTU size for Ethernet in octets is (eight-bit bytes), which can be transmitted in a packet or frame across the network.

TCP uses MTU while transmitting packets between devices connected to the internet.

If an MTU size is large and can’t be managed by a router, then it will be retransmitted.

Similarly, a small MTU size will consume too much bandwidth while transmitting.

Users can also configure PPPoE directly from their PC. All the major operating systems, including Windows, Mac, and Linux, support PPPoE, so configuration is straightforward.

However, for manually configuring PPPoE on a PC, you must have your PPPoE account information, including service name, username, and password.

Again, this information should be provided to you by your ISP. Once you set up the connection, it will work unless your connection is not upgraded or impacted by any other operation.

PPPoE vs. DHCP

DHCP refers to the Dynamic Host Configuration Protocol.DHCP is the latest technology that replaces the PPPoE.

With DHCP, admins can easily automate the process of IP address assignment. DHCP has central points to monitor and distribute addresses. These central points make DHCP centralized and convenient.

If DHCP is not configured, then administrators must manually configure IP addresses.

On the other hand, PPPoE is opposite to DHCP. The PPPoE protocol needs to be configured beforehand.

Shortly, PPPoE needs credential access to assign a unique IP address, while DHCP doesn’t need authentication for an IP address assignment.

Both PPPoE and DHCP function differently. The PPPoE allows PPP communication over the Ethernet. The DHCP assigns IP addresses without authentication.

Conclusion

Hopefully, you have now understood what is PPPoE and why we use it. I tried my best to explain the concept of PPPoE and DHCP. The PPPoE, or the Point-to-Point Protocol over Ethernet technology, has been adopted by ISPs worldwide to assign IP addresses to clients.

The PPPoE first requires creating a username and password for assigning an IP address. However, in DHCP, the IP addresses will be assigned automatically without any authentication.