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Software Configuration Guide—Release 15.0(2)SG
OL-23818-01
Chapter 41 Configuring the PPPoE Intermediate Agent
Related Documents
Related Documents
RFCs

About PPPoE Intermediate Agent

PPPoE Intermediate Agent (PPPoE IA) is placed between a subscriber and BRAS to help the service
provider BRAS distinguish between end hosts connected over Ethernet to an access switch. On the
access switch, PPPoE IA enables Subscriber Line Identification by appropriately tagging Ethernet
frames of different users. (The tag contains specific information such as which subscriber is connected
to the switch and VLAN.) PPPoE IA acts as mini security firewall between host and BRAS by
intercepting all PPPoE Active Discovery (PAD) messages on a per-port per-VLAN basis. It provides
specific security feature such as verifying the intercepted PAD message from untrusted port, performing
per-port PAD message rate limiting, inserting and removing VSA Tags into and from PAD messages,
respectively.

Enabling PPPoE IA on a Switch

This functionality allows you to enable or disable PPPoE IA globally on the switch:
Switch> enable
Switch# configure terminal
Switch(config)# pppoe intermediate-agent
By default, PPPoE IA is disabled globally.

Configuring the Access Node Identifier for PPPoE IA on a Switch

This functionality allows you to set the Access Node Identifier of the switch. If unspecified, this
parameter is derived automatically with the IP address of the management interface.
Related Topic Document Title
PPPoE Circuit-Id Tag Processing Refer to the PPoE Circuit-Id Tag Processing chapter
RADIUS attributes Refer to the Cisco IOS Security Configuration Guide, Release 12.4
DSL Forum Line-ID tag solution DSL Forum 2004-71: Solution for Remote-ID in PPPoE Discovery
Phase
Migration to Ethernet-based DSL aggregation DSL Forum Technical Report 101
RFC Title
RFC 2516 A Method for Transmitting PPP over Ethernet (PPPoE)