Juniper JUNOSE 11.1.X - LINK LAYER CONFIGURATION 4-7-2010 Configuration Manual page 559

Encapsulation type lockout is performed by default. You can configure the lockout
time range by issuing the auto-configure command with the optional lockout-time
keyword.
The following guidelines describe lockout behavior:
Any encapsulation type that you do not configure for autodetection with the
auto-configure command is automatically locked out.
You can permanently lock out a specified encapsulation type from autodetection
and prevent dynamic interface creation by issuing a no auto-configure command
for the specified encapsulation type, if previously configured.
When an encapsulation type is locked out, the router continues to autodetect
the remaining encapsulation types and create the dynamic interfaces.
For the IP and bridged Ethernet encapsulation types, temporary lockout occurs
automatically on receipt of an authentication deny response from RADIUS when you
attempt to create and configure a dynamic IPoA or dynamic bridged Ethernet
interface.
The lockout time range comprises two values: a minimum lockout time and a
maximum lockout time. The initial lockout time begins with the minimum lockout
time. From this point, the lockout time increases exponentially for every successive
lockout event within the greater of 15 minutes or the maximum configured lockout
time. The lockout time never exceeds the maximum value of the time range.
For example, using the default lockout time range of 1–300 seconds, the increasing
lockout time sequence is: 1 second, 2 seconds, 4 seconds, 8 seconds, 16 seconds,
32 seconds, 64 seconds, 128 seconds, 256 seconds, and finally, 300 seconds
(5 minutes).
Guidelines for Configuring Encapsulation Type Lockout
The following rules apply when you configure the lockout time for dynamic
encapsulation type lockout:
The lockout time value is defined as
(minimum lockout time) * (2 ^ n-1)
where n represents the number of consecutive lockout events.
The router increments the value of n when the time between lockout events is
either within 15 minutes or the maximum lockout time, whichever is greater.
When the time between lockout events is greater than either 15 minutes or the
maximum lockout time, the value of n reverts to 1. This condition is referred to
as a grace period.
The lockout time never exceeds the maximum configured lockout time. For
example, for a configured lockout time in the range 20–120 seconds, the
increasing lockout time sequence is 20 seconds, 40 seconds, 80 seconds, and
finally, 120 seconds.
Chapter 17: Configuring Dynamic Interfaces
About Configuring Dynamic Interfaces over Static ATM
527