Dynamic Interface Creation - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - LINK LAYER CONFIGURATION GUIDE 2010-10-13 Configuration Manual

Copyright © 2010, Juniper Networks, Inc.
Subscriber packets received from the DSLAM are double-tagged with both an S-VLAN
ID and a VLAN ID
The DSL Forum Technical Report (TR)-101—Migration to Ethernet-Based DSL Aggregation
(April 2006) refers to the behavior of these configurations as the 1:1 forwarding model
because there is a one-to-one correspondence between an individual subscriber and the
VLAN encapsulation.
In contrast, the following configurations do not uniquely identify subscribers by means
of VLAN encapsulation:
Subscriber packets received from the DSLAM are single-tagged with the same VLAN
ID for a group of subscribers. This configuration is typically used to implement service
VLANs where the VLAN ID corresponds to the type of service for which the VLAN is
used, such as voice or video. In this configuration, the VLAN ID does not correspond to
an individual subscriber.
Subscriber packets received from the DSLAM are untagged.
Instead, these configurations identify subscribers by means of the agent-circuit-identifier
information present in DHCP and PPPoE control messages. DSL Forum TR-101 refers to
the behavior of these configurations as the N:1 forwarding model because there is a
many-to-one correspondence between subscribers and a VLAN.
Creating dynamic VLANs based on agent-circuit-identifier information enables you to
manage subscribers in single-tagged or untagged N:1 configurations that do not use
encapsulation to uniquely identify subscribers. In these configurations, the router intercepts
the agent-circuit-identifier string from DHCP messages or from PPPoE PADR and PADI
packets to build a unique subscriber interface.
For double-tagged 1:1 configurations, the router uses standard dynamic VLAN procedures
to uniquely identify subscribers. In these configurations, the S-VLAN ID typically represents
the DSLAM, and the VLAN ID represents the individual subscriber accessing the router
through that DSLAM.
For configuration instructions, see "Configuring Dynamic VLAN Subinterfaces Based on
Agent Circuit Identifier Information" on page 663.
NOTE: You must configure the DHCP local or external server to support the
creation of dynamic subscriber interfaces that are based on the
agent-circuit-id option (suboption 1) of the option 82 field in DHCP messages.
See Configuring the DHCP Local Server or DHCP External Server Overview
for information.

Dynamic Interface Creation

After you configure the base profile, you associate it with the VLAN major interface by
issuing "profile vlan bulk-config" on page 667 .
Chapter 18: Configuring Dynamic Interfaces Using Bulk Configuration
659