Pppoe Overview; Pppoe Configuration - Avaya G250 Administration

Configuring WAN interfaces

PPPoE overview

PPPoE is a client-server protocol used for carrying PPP-encapsulated data over Ethernet
frames. A PPPoE client can establish a tunnel that carries PPP frames between a dialing host
(the G250/G350) and an access concentrator. This enables the use of PPP authentication
protocols (CHAP and PAP). Unlike other tunneling protocols such as L2TP and PPTP, PPPoE
works directly over Ethernet rather than IP.
A typical broadband access network is based on aDSL modems configured as transparent
Ethernet bridges. aDSL modems use ATM protocol, and the transparent bridging is done to a
well known ATM VC. On the other side of the telephone line is a device called a DSLAM. The
DSLAM terminates the aDSL physical layer, collects the ATM cells from the various aDSL
subscribers, and places them on the SP ATM infrastructure. The Ethernet frames from the
customer's host device can reach one or more access concentrators, which are the remote
access servers.
Figure 15: Typical PPPoE Network Topology
G250/G350
ETH-WAN
Ethernet
DSL Modem

PPPoE configuration

To configure PPPoE on the Fast Ethernet port:
1. Enter the context of the Fast Ethernet interface, using the command interface
FastEthernet 10/2.
2. Use the encapsulation pppoe command to change the encapsulation to PPPoE. You
must change the encapsulation to PPPoE before configuring an IP address on the interface.
140 Administration for the Avaya G250 and Avaya G350 Media Gateways
PPP
PPPoE
ATM over DSL
DSLAM
ISP A
L2TP
Access Concentrator/
PPPoE Relay
ATM
Access Concentrator
ISP B