ZyXEL Communications OLT2406, User Manual

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Chapter 102 PPPoE IA
OLT2406 User’s Guide
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PPPoE IA
102.1 Overview
This chapter describes how the OLT gives a PPPoE termination server additional information that the
server can use to identify and authenticate a PPPoE client.
102.2 PPPoE Intermediate Agent Overview
• PPPoE allows ISPs to manage accounts access from dial-up Internet (such as ADSL).
• A PPPoE Intermediate Agent (PPPoE IA) is deployed between a PPPoE server and PPPoE clients.
Figure 294 PPPoE IA in Network
• PPPoE IA helps the PPPoE server identify and authenticate clients by adding subscriber line specific
information to PPPoE discovery packets (PADI, PPPoE Active Discovery Initiation, and PADR, PPPoE
Active Discovery Request) from clients on a per-port or per-port-per-VLAN basis before forwarding
them to the PPPoE server.
• PPPoE Intermediate Agent is defined in “DSL Forum Technical Report 101-Migration to Ethernet-Based
DSL Aggregation” (TR-101).
• If a PADI or PADR packet exceeds 1500 octets after adding the subscriber line specific information,
the PPPoE IA does not send the packet to the PPPoE server but sends the packet with a Generic-Error
TAG back to the sender (client).
102.2.1 Port State
Every port is either a trusted port or an untrusted port for the PPPoE intermediate agent. This setting is
independent of the trusted/untrusted setting for DHCP snooping or ARP inspection. PPPoE IA inserts
access loop identification in the packets sent from non-trusted ports to trusted ports. You can also
specify the agent sub-options (circuit ID and remote ID) that the OLT adds to PADI and PADR packets
from PPPoE clients.
Trusted ports are connected to PPPoE servers.