Auto-Configure Command; Encapsulation Type Lockout - Juniper JUNOSE SOFTWARE 11.2.X - LINK LAYER CONFIGURATION GUIDE 7-7-2010 Configuration Manual

auto-configure Command

Copyright © 2010, Juniper Networks, Inc.
You use the auto-configure command to configure an ATM 1483 subinterface to support
a dynamic interface. After the subinterface is configured, it performs autodetection to
identify the encapsulation, resulting in the dynamic creation of the higher protocol layers.
This command specifies one or more types of next upper dynamic encapsulations that
the static interfaces can detect or accept.
NOTE: On static ATM 1483 interfaces, dynamic encapsulation types can be bridged
Ethernet, IP, IPv6, PPP, or PPPoE.

Encapsulation Type Lockout

You can configure E Series routers to support dynamic encapsulation type lockout. With
this feature, you can temporarily prevent an ATM 1483 subinterface from autodetecting,
accepting, and creating dynamic interface columns for a configurable time period.
On ATM 1483 subinterfaces, encapsulation type lockout is the default behavior for IPoA,
bridged Ethernet, PPP, and PPPoE encapsulation types.
Benefits
Using dynamic encapsulation type lockout provides the following benefits:
Enables autodetection of other encapsulation types when a dynamic interface for a
specified encapsulation type cannot be created.
For example, when running a PPPoE client, DSL modems might transmit bridged
Ethernet frames among the PPPoE frames. When bridged Ethernet and PPPoE
encapsulation types are configured for autodetection with the auto-configure
command, and a subscriber is configured for the bridged Ethernet encapsulation type,
RADIUS sends a deny response after the router attempts to authenticate a received
bridged Ethernet frame. Receiving an authentication denial from RADIUS causes the
router to lock out bridged Ethernet. By locking out bridged Ethernet frames, the router
can receive PPPoE frames unimpeded, facilitating rapid creation of dynamic PPPoE
interfaces.
Reduces loading on the RADIUS server.
In some cases, IP and bridged Ethernet interfaces configured with a local subscriber
do not have a corresponding subscriber entry in the RADIUS database. This can occur
inadvertently due to misconfiguration of the E Series router or RADIUS server, or
intentionally as a way to prevent creation of dynamic IPoA or bridged Ethernet
interfaces.
In previous releases, when the ATM 1483 interface received a deny response from
RADIUS due to the missing subscriber entry, it performed continuous authentication
retries every few seconds, which caused significant loading on the RADIUS server.
Locking out autodetection of the IP or bridged Ethernet encapsulation type for a
configurable time period prevents detection of dynamic IPoA or bridged Ethernet
interfaces and reduces loading on the RADIUS server.
Chapter 17: Configuring Dynamic Interfaces
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