Pppoe Client Fundamentals - Nortel Secure 4134 Configuration

PPPoE client fundamentals

PPPoE (RFC 2516) is a commonly used application in the deployment of
DSL One of the main advantages of PPPoE is that it offers authentication
based on Password Authentication Protocol (PAP) or Challenge Handshake
Authentication Protocol (CHAP).
With the SR4134, the PPPoE client must be deployed with a DSL modem
providing a connection to a PPPoE server for access to Internet resources.
The main purpose of PPPoE is to serve as a backup and fail-over solution.
When the primary connectivity goes down, traffic can switch over to a
backup interface, in this case the virtual PPPoE interface. In this scenario,
a PPPoE client session is established with a PPPoE server and traffic is
routed through this path until the primary connectivity is restored.
The PPPoE client only transmits traffic if it is up and running and a route
lookup picks a route pointing to the PPPoE interface.
For PPP to run over Ethernet, it needs to learn the Ethernet address of the
remote peer, and establish a session ID. In order to do this the PPPoE
protocol defines a discovery stage, followed by a session stage. In the
discovery stage the host acts as a client and the remote access concentrator
acts as a server. This allows the host to learn the Ethernet address of the
remote peer and to set up a session ID. After the discovery stage, the
session stage begins with the normal PPP LCP and IPCP negotiation.
On the SR4134, the PPPoE client supports the following features
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Copyright © 2007, Nortel Networks
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The client connection to the PPPoE server is established when the
client is configured.
Traffic is routed to the PPPoE based on route selection. When the
optimal route becomes inactive and a route pointing to the PPPoE
interface is active, traffic switches over to the PPPoE interface. Traffic
stops using the PPPoE interface when a more optimal route becomes
active.
The PPPoE client can learn its IP address from the remote PPPoE
server.
The PPP session sends keepalives at a regular interval to detect PPPoE
server failure.
Nortel Secure Router 4134
Security — Configuration and Management
NN47263-600 01.02 Standard
10.0 3 August 2007
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