Dynamic Interface Creation - Juniper JUNOSE 11.1.X - LINK LAYER CONFIGURATION 4-7-2010 Configuration Manual

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 669.
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 674 .
Chapter 18: Configuring Dynamic Interfaces Using Bulk Configuration
Configuring VLAN Dynamic Subinterfaces
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