PPPoE/v6 Administrator's Guide

Introduction

Protocol Overview

Chapter 1 13

Protocol Overview

Any PPPoE session typically comprises two peers communicating over

an Ethernet link. Each peer must learn the Ethernet address of the

remote peer and also establish a unique session identiﬁer that identiﬁes

the PPPoE session between the peers. Figure 1-2 depicts how the PPPoE

client and the server, on the same link, communicate with each other.

Figure 1-2 When Client and Server Are on the Same Link

You need an optional relay when there is a router in between the PPPoE

client and the server. In such cases, the relay receives packets from the

clients and transmits them on the other link to the server and from the

server to the client. See Figure 1-3 for information on how the client

connects to the server via a relay.

Figure 1-3 When Client and Server Are on Different Links

PPPoE

Client

PPPoE

5.6.7.8

1.2.3.4

Server

fe80::9

fe80::10

PPPoE

Client

PPPoE

Server

Relay

5.6.7.8

fe80::10

fe80::9

1.2.3.4

lan0

lan4